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[Articles Home]  [Add Article]  

Relatively Easy Solar Power

from Ken, WI7B on April 4, 2009
Website: http://wi7b.org/
View comments about this article!

Relatively Easy Solar Power
Running your station HF and VHF/UHF radios on renewable solar energy.

The point of this short article is to show that a station based on renewable solar power is within the reach of any radio amateur for the price of a mobile rig and, honestly, minimal effort. I've taken a 15 Watt amorphous silicon solar panel (shown above) and fitted it to the metal roof above the shack. It's used to trickled-charge a 12V deep-cycle battery. Diode-blocking protects the panel from reverse current as the battery reaches full charge. In direct sunlight, the panel produces 20V unloaded. However, it is able to provide charge even in overcast and rainy conditions. It was purchased from Silicon Solar for under $120.

The deep-cycle 12V 33 amp-hours (AH) SLA absorbed glass matt (AGM) battery with the finished wire set is displayed above. Although it is capable of working in a range of temperatures, maximum efficiency is maintained by keeping the battery inside. AGM technology allows 99% of produced hydrogen and oxygen gases to recombine in the battery, while acid leaking is mitigated. It was purchased at a Battery-Plus mall outlet for under $80.

In typical use, the battery is charged-up by a mean 10% of its AH capacity per day. This allows just under 10 minutes of 100% transmit capacity at 100W on my Kenwood rig for total renewal. For emergency use (non-diurnal renewing) this can be extended to 60% of battery capacity (19.8 AH) or about 55 minutes of transmit without detrimental effect.

Member Comments:
This article has expired. No more comments may be added.
 
Relatively Easy Solar Power  
by KC9ATJ on April 4, 2009 Mail this to a friend!
Not to bad of a start to an article. I'm just trying to figure out where you got some of your numbers? I'm figuring about 1 A an hourfrom your panel average. If the panel is providing 10% of your battery power, that translates into about 10 A. Your average 100 W rig pulls about 20 A max. So it should last about 1/2 hour with 100% transmit (which unless your running only 100% duty cycle modes, will translate into about 1:15 or so of QSOs assuming a 2:1 listen:transmit ratio is used).

I think what you did was you didn't take into account the fact that batteries are rated in Ah. This means that it should operate at xA for 3 hours when fully charged. So that means that you could operate your average 100 W rig for about 5 hours on your battery at 100% duty cycle.

I'm not saying that you did a bad job at writing this or anything, but I'm just trying to help you understand how things work better.

Joel
KC9ATJ
 
RE: Relatively Easy Solar Power  
by N2EY on April 4, 2009 Mail this to a friend!
KC9ATJ writes: "I'm figuring about 1 A an hourfrom your panel average."

Solar PV panels are rated with full sun hitting the panel straight-on. When the sun hits the panel at an angle, or there are clouds, the output is less.

So that 15 watt rating is maximum, and you might get 1 A max from the panel when sun and panel are perfectly aligned. The rest of the day you get less.

KC9AT: "If the panel is providing 10% of your battery power, that translates into about 10 A."

But the panel doesn't provide 10 AH per day, even on a sunny day.

There are "solar insolation maps" (that's not a typo) which give the equivalent amount of full sun to be expected in various places at various times of the year for a fixed panel. My guess is that the author's panel provides maybe 6 AH per day.

KC9AT: "Your average 100 W rig pulls about 20 A max. So it should last about 1/2 hour with 100% transmit (which unless your running only 100% duty cycle modes, will translate into about 1:15 or so of QSOs assuming a 2:1 listen:transmit ratio is used)."

It's more complicated than that.

Suppose the transmit-receive ratio is 1:3 (the duty cycle is such that it's equivalent to 100% transmit power for 25% of the time, and receive power for 75% of the time). And suppose the rig draws 2 A on receive and 20 A on transmit.

Then, in one hour's operating time, the rig will use 5.5 AH from the system. (0.25 x 20 = 4 plus 0.75 x 2 = 1.5) Which is about the average daily output of the panel.

Batteries are not 100% efficient - you don't get back all the charge you put in. So while the transmit-time numbers given by the author may be a bit conservative, I don't think they are far off the mark.

KC9ATJ: "I think what you did was you didn't take into account the fact that batteries are rated in Ah. This means that it should operate at xA for 3 hours when fully charged. So that means that you could operate your average 100 W rig for about 5 hours on your battery at 100% duty cycle."

Battery ratings are complex, and vary with the load, temperature and final cell voltage. The usual rating is the 8 hour rating - how many amps the battery can supply for 8 hours, to a final-voltage rating of so many volts. For example, an "80 AH at the 8 hour rate" battery can supply 10 amps for 8 hours. However, the same battery may be able to supply 20 amps for only 2 hours (40 AH at the two-hour rate) before reaching final voltage. It depends on the battery and the conditions.

Battery life in lead-acid types is directly related to how deeply the battery is discharged during each cycle. It's clear to me that one concern of the author was that the battery not be deeply cycled, so it will last longer.

There's also the fact that a lot of rigs won't operate below a certain voltage - or won't operate correctly. Many manufacturers rate their batteries to 1.75 volts-per-cell final voltage, which in a 6 cell battery works out to 10.5 volts. But will the rig in question operate correctly at 10.5 volts? If not, the effect is to derate the battery.

I think the author's main point is valid in that a PV system doesn't have to be complex or super-expensive to be useful. While the system shown doesn't provide lots of hours of operation, it does provide some, plus backup when AC power fails. Careful choice of a rig and power level can make a big difference in operating time.


73 de Jim, N2EY
 
RE: Relatively Easy Solar Power  
by N2EY on April 4, 2009 Mail this to a friend!
I took a peek at:

http://www.energyatlas.org/PDFs/LowRes/atlas_state_WA.pdf

and found that, for the author's QTH, the average daily solar insolation is 4.6 to 5.0 hours per day. IOW, a fixed panel that is set up to optimize the available sunshine will get the equivalent of 4.6 to 5.0 hours of full sun per day - on average. That works out to between 1679 and 1825 hours per year.

For a 15 watt panel, that means a total of between 25 and 28 kilowatt-hours per year of electricity from the panel. Since the system is not 100% efficient due to diode and battery losses, the actual useful energy is probably between 20 and 25 kilowatt-hours per year.

73 de Jim, N2EY
 
Relatively Easy Solar Power  
by K4MTN on April 4, 2009 Mail this to a friend!
Ken: Nice article showing that it not that difficult or expensive to provide emergency power to your rig. Every ham involved in emergency work should have this capability.
To the others, lighten up.
Andy
 
Relatively Easy Solar Power  
by KH6AQ on April 4, 2009 Mail this to a friend!
Ken,

thanks for writing this article. I did not know it could be done this inexpensively.
 
Relatively Easy Solar Power  
by KD4LLA on April 4, 2009 Mail this to a friend!
OK, it's a start. But your recharge rate of 1 amp will not last in actual practice. Only get direct sun for about 5 hours a day, since the panel does not track the sun. A trickle charger is just enough to keep up with the loss a battery sustains normally. I have a 60 watt panel at my shack (non tracking), going to a 10 amp charge controller, to a deep cycle battery. My system is barely adequate.

Mike
 
Harbor Freight panels?  
by K9ZF on April 4, 2009 Mail this to a friend!
Interesting, but short article. Thanks for sharing.


Has anyone used the cheap panels from Harbor Freight? They have them on sale pretty cheap from time to time. If I recall, they come as a set of 3, fifteen watt panels, for a total of 45 watts.

The author had a good start, but I would want a small "bank" of batteries, I believe. And I don't like keeping them inside, even the SLA's...


73
Dan
--
Amateur Radio Emergency Service, Clark County Indiana. EM78el
K9ZF /R no budget Rover ***QRP-l #1269 Check out the Rover Resource Page at:
<http://www.qsl.net/n9rla> List Administrator for: InHam+grid-loc+ham-books
Ask me how to join the Indiana Ham Mailing list!

 
Relatively Easy Solar Power  
by KG4TKC on April 4, 2009 Mail this to a friend!
Nice article on an interesting subject. It seems to me that the thing to do with this nice install,is to try to add to it to increase power/time use. One panel,one battery as shown here is an excellent start. Perhaps next year,if money allows,another panel and another battery.And the next year the same if money allows. Just as a telecom CO does,add more to the rectifier/battery string to be able to provide power for a longer time. It looks to me like WI7B is off to a great start here. Thanks for sharing with us WI7B.
 
RE: Relatively Easy Solar Power  
by AD5LT on April 4, 2009 Mail this to a friend!
Nice basic building block which in time can be improved upon in time. I found this article online (wind power)which could supplement this set up or used by itself with improvements. I have wind here every day and the basic parts are fairly inexpensive. Take a peak here http://www.mdpub.com/Wind_Turbine/index.html
Just keep in mind that this is a building block that can be improved upon
 
RE: Relatively Easy Solar Power  
by K0BG on April 4, 2009 Mail this to a friend!
Jim, N2EY brings up some interesting points, and some real truths about the cost of photovoltaics. If you have to rely a on solar/battery to provide all of your operating power, things aren't so cheap!

Four years ago, I investigated a system for a repeater site which could supply about 500 watts average, over a 24 hour period. The cost was just shy of $31,000 just for the panels! Considering our insolation factor is above average for the US, that's a lot of bread!

Considering what the author paid out, I think he got a bargain even if the aH rating is as small as it is.

Alan, KBG
www.k0bg.com
 
RE: Relatively Easy Solar Power  
by K5END on April 4, 2009 Mail this to a friend!
Excellent article.

Nice set up.

Great job.

Thanks for posting it.

73
 
RE: Relatively Easy Solar Power  
by NA0AA on April 4, 2009 Mail this to a friend!
I was in Kragen/Shucks auto parts, they had a 15 watt panel, similar to the one in the article but with a plastic frame, for $99. It includes a 7 amp controller, which would allow you to add a number of additional panels.

I've done a fair bit of research into solar panels, particularly with an interest in field day off the grid by solar. Sadly, the problem boils down to this, and I'm using very rough numbers just so you can replicate my work with your own equipment.

Hours of sunlight for Charging: I'll use 6 hours

Amps provided by panel: 5 amps

Multiply by .8 for efficiency in battery charging:

Amp/hours delivered:

So just for a simple example:

6 hours X 5 amps x .8 = 14.4 amp/hours

Radio: I figure that a 100 watt radio probably draws a real 10 amps AVERAGE during transmit, and it's best to meter your receive draw. But, let's say that for field day:

1 Hour: 24 minutes transmit, 36 minutes receive [worst case]:

10 amps x .4 hour = 4 amp/hr

.6 amps x .6 hour = .36 amp/hour

so you will consume roughtly 4.36 amp/hours per hour of operation

So your panel and battery above is good for about 3.5 hours [14.4/4.36] of daily operation when the sun is shining 6 hours per day, plus if the batteries are fully charged when you start operating, your panels will keep the battery fully charged until panel sunset.

Sadly, what this means practically is that in order to do 24 hours of field day with intense operation you need about 144 amp/hours of power, which requires quite a bit of panels or a lot of dead batteries at the end of the weekend.

As you can see from the numbers above, you are rewarded by shorter transmit times, but that will not improve your field day score.

If I were installing such a system, I'd start with a comprehensive amp-meter analysis of my power consumption of my station. That would determine the overall panel sizing.

Battery capacity is usually best determined by station draw plus the number of backup DAYS you want to store, plus your evaluation of your daily battery bank draw-down.

Using the extreme example above, almost 80 amp hours would be needed from the batteries every night, so make up would be:

4.36 X 24 hours = 105 amp/hours.

105 / 6 hours sunlight = 17.5 amp/hours of RETAINED charge, so about 22 amps of charge current.

In the real world, few amateurs operate with that level of intensity on a daily basis, so it's more economical to buy a bigger battery or even use mains power in the event of dark days.

If it were ME doing the planning for my station, I'd calculate storage capacity based on no more than 20% of the battery capacity drained during the night cycle - this makes sure that the batteries cycle but not deeply [makes them last much longer], plus it gives a couple of days of reserve power before you have to use alternate charging methods.

Obviously if some one gifts you with some immense used telco cells, one would be foolish to turn up ones nose at them though.

 
Relatively Easy Solar Power  
by KC8VOV on April 4, 2009 Mail this to a friend!
Great idea and article. Http://www.harborfreight.com is offering a 45W panel set for $199.99. I have been using one of their 5W panels with a deep cycle battery on a gate opener for over a year now with no problems.
 
RE: Relatively Easy Solar Power  
by K7AAT on April 4, 2009 Mail this to a friend!

Nice article, but I agree with others, including KG6WOU above on the re-assessments of the calculations. That 15W panel is basically just keeping your battery from running down quite as fast as it normally would for a moderately active ham shack. Still... far better than nothing... and would be easy to supplement with larger solar power when your budget allows.

I run something similar, but have a small AC regulated power supply also floating my battery at 13.6 VDC. It provides the vast majority of battery charge, but when the power goes out, the Solar panel I have is still there ( 50W panel ).

One last question, though... why do you need a diode from the Solar panel to the Battery bank? The Solar Panel IS a diode ( or series of them ). An additional Diode mainly only serves to lower your Charging Voltage to the Battery... ergo less current, too. I rarely use a diode in my solar arrays, but I DO fuse them.

Ed K7AAT

 
RE: Relatively Easy Solar Power  
by WI7B on April 4, 2009 Mail this to a friend!

Thanks for insight, OMs!

Just a short clarification. My diurnal charge-up time wasn't a calculation, it was a measured mean or average time since I started operating on solar energy based solely on my battery's operating voltage - again an approxmation of AHs or WHs. I don't talk alot in the evening, so even 10 minutes transmit on SSB and a little PSK31 is good for me.

And, as pointed out, its super expandable. I will look inot HArbor Freight since we have a store right here in town,

73,

---* Ken
 
RE: Relatively Easy Solar Power  
by N6AJR on April 4, 2009 Mail this to a friend!
I have a small panel on the garden shed hooked up to the riding lawn mower battery. It always starts, this panel is about a foot square and sends out about 175 mills tops, but it keeps the lawn tractor battery up, I have had this mower 10 years or so and it is the original battery.

I use an second panel hooked to my harley battery to keep it "up" when not riding it.


I also have a very small panel in the window of the pickup. I don't drive it often and theis keeps the batery up on the truck.

I have a couple of 85 watt panels and a controler for them I was going to use inj a trailer, but I sold the trailer, so re=cently I bought a Grid tie inverter that uses 2 panels in series and it back feed the gris. I has built in blocking diodes, and also is full sine wave. it takes a sync from the grid and if the power goes out it drops off line automatically, so no "island effect" to kill a lineman. Y ou hook the panels up to the input and plug it into the wall socket, and you can stack up to 4 of them for up to m1000 watts each does 250 watts, and they also have them for wind nmills.

I loke solar and use it all the time.

BTW you can also pick up a small 3 stage charger and use it to keep up a larger bank of deep cycle batteries either from A & A Engineering or one of thr small motorcycle msaintenance chargers.( also called automatic battery tenders.)

lots of ways to do it..
 
Relatively Easy Solar Power  
by N8RGQ on April 4, 2009 Mail this to a friend!
First go to Radio Shack and pick up a Voltage Regulator 12V 1.5 Amp Cat-Number 276-1771 $2 and stop feeding the battery with up to 20 Vdc ! The battery plates don't like that much Voltage . If you don't you will really shorten it's lifespan !

I run four Sharp 142w solar panels and the Morning star TS-60 controller into four Interstate 8D DEEP-CYCLE batteries . It runs my setup without a hitch 24-7 :)
73,
Terry
N8RGQ
 
RE: Relatively Easy Solar Power  
by N2EY on April 4, 2009 Mail this to a friend!
K0BG mentions "some real truths about the cost of photovoltaics"


Well, let's look at some numbers...

The system described, in a location with about 5 hours of sun per day, probably gives about 20 kWh of usable electricity per year. And it cost about $200.

Residential electricity rates vary all over the place in the USA, a fact that isn't widely publicized. Imagine if gasoline were $4/gallon in New York but only $1/gallon in Seattle...

If you pay 20 cents per kWh, that's $4 return on a $200 investment - ROI of 2%. If you pay 5 cents per kWh, that's $1 return on $200 investment - ROI of 0.5%. Depending on how long the system lasts, and what happens to electricity rates in the future, that may or may not be acceptable to you. (You can also get a lot more out of a system like the one described if you're willing to run QRP, or just turn down the power to 25-50 watts instead of the usual 100.)

OTOH, the PV system still works when the power fails, which is a very big deal if you have frequent outages. Depending on how the system is installed, it may be practical to unplug/unbolt the components and take them with you on Field Day, vacation and other ham activities away from home, rather than lugging along a generator, gasoline, etc.

And you have to compare apples to apples; if the PV system eliminates the need to buy or build a regulated supply for your rig, the cost is reduced by the cost of that supply.

Where PV systems really shine (pun intended) is in applications where getting power to the site is very expensive. In some cases the cost of running a power line (if it can be done at all) is more than a PV system.

73 de Jim, N2EY
 
RE: Relatively Easy Solar Power  
by AA4PB on April 4, 2009 Mail this to a friend!
You need a solar charge controller or you will cook the battery in a relatively short time if the radio is turned off. If the no load voltage of the solar panel is 20V then it will keep pumping current into the battery until the battery reaches 20V - but its only a 12V battery! 12V lead-acid batteries are designed to float at 13.8V, not 20V.

A charge controller will permit all of the panel's capacity to be used when the battery needs charging but limit the charge voltage when the battery doesn't need charging. While a 13.8V voltage regulator would work to prevent overcharging, it would not permit the solar panel to to use all of its output for charging when the battery can use it. A series mode voltage regulator would turn much of the generated power into heat in the regulator instead of using it to charge the battery.

You've got to be careful of charge controllers around radio receivers because many of them generate RF hash in the circuits used for switching.
 
RE: Relatively Easy Solar Power  
by N2EY on April 4, 2009 Mail this to a friend!
KG6WOU writes: "field day off the grid by solar. Sadly, the problem boils down to this, and I'm using very rough numbers just so you can replicate my work with your own equipment.

Hours of sunlight for Charging: I'll use 6 hours"

I think that's overly conservative. Here's why:

First, Field Day is very close to the summer solstice, when the daylight is longest. Here in EPA, the daylight on FD weekend is typically at least 16 hours.

In addition, on FD it's not a big deal to have someone detailed to reorient the panels every hour or so in order to get the most usable energy from them.

On top of that, FD starts at 2 PM on the east coast and 11 AM on the west coast, so you have several hours before the beginning to get the batteries fully charged.

KG6WOU: "Amp hours delivered:

6 hours X 5 amps x .8 = 14.4 amp/hours"

I'd say it's more like 30 AH because of the longer days on FD and being able to move the panels.

KG6WOU: "1 Hour: 24 minutes transmit, 36 minutes receive [worst case]:

10 amps x .4 hour = 4 amp/hr

.6 amps x .6 hour = .36 amp/hour

so you will consume roughtly 4.36 amp/hours per hour of operation"

I agree with those numbers.

KG6WOU: "So your panel and battery above is good for about 3.5 hours [14.4/4.36] of daily operation when the sun is shining 6 hours per day, plus if the batteries are fully charged when you start operating, your panels will keep the battery fully charged until panel sunset.

Sadly, what this means practically is that in order to do 24 hours of field day with intense operation you need about 144 amp/hours of power, which requires quite a bit of panels or a lot of dead batteries at the end of the weekend."

I disagree!

If the PV system output is a bit more than the rig's average demand, the only thing the battery really has to do is take you through the hours of darkness. If we assume 10 hours of darkness (which is a lot more than we get in many places), that's 43.6 AH to get through the night. Say 80 or 90 AH so the battery isn't drained beyond 50% of capacity.

A lot depends on the kind of operating you do on FD, too. If your setup is such that you can hold a frequency and run stations, your transmit duty cycle will be higher than if you hunt-and-pounce. A seemingly-small difference in rig efficiency (such as a rig that only needs 18 A on tx and 1 A on rx compared to one that needs 20 A on tx and 3 A on rx) can make a big difference in how much PV you need.

As for cost, not having to drag along a generator, gasoline, extension cords, power supplies fire extinguisher and other goodies may be worth lugging the panels, batteries and controller. (The panels can be close to the operators because they don't make noise!) Also, the use of a PV system may permit you to access FD sites where running a generator all night wouldn't be allowed.

KG6WOU: "Obviously if some one gifts you with some immense used telco cells, one would be foolish to turn up ones nose at them though."

That depends on their condition. One reason old batteries are disposed of is that their self-discharge rises and their actual capacity drops.

Note too that the panel and battery size have to match. All storage batteries self-discharge over time, so a small panel and big battery won't work because the panel will be doing all it can just to make up the self-discharge of the big battery. (IIRC, the self-discharge of most battery types is a few percent per day, so for the 80 AH battery used in the author's system, less than 1 AH per day will keep it happy).

The best storage batteries I've ever worked with were the big Edison nicad wet cells. Almost indestructible, efficient, last forever. Also very expensive and you need 9 or 10 of them in a 12 volt battery because their cell voltage is lower.

73 de Jim, N2EY
 
RE: Relatively Easy Solar Power  
by N2EY on April 4, 2009 Mail this to a friend!
K7AAT writes: "That 15W panel is basically just keeping your battery from running down quite as fast as it normally would for a moderately active ham shack."

I don't think that's true, given the size of the battery and panel. How much self-discharge does that battery have?

K7AAT: "why do you need a diode from the Solar panel to the Battery bank? The Solar Panel IS a diode ( or series of them )."

Because it's a string of diodes pointing in the wrong direction. When in the dark, the battery will discharge through the panel.

73 de Jim, N2EY

 
RE: Relatively Easy Solar Power  
by W8AAZ on April 4, 2009 Mail this to a friend!
Oh well he can work alot of repeaters or QRP HF. My rig has a power level knob setting. I could make do with the lower duty cycle modes. Wonder how long it would last on PSK? It is a start and shows initiative. He might have the last laugh some day with free power in any quantity.
 
Relatively Easy Solar Power  
by AB6ND on April 4, 2009 Mail this to a friend!
What's all this 100W stuff.

If it's for an emergency back up, surely 5 or 10 watts should be sufficient. Just make sure the antenna stays aloft.

ab6nd


 
RE: Relatively Easy Solar Power  
by AC7CW on April 4, 2009 Mail this to a friend!
Nice article, thanks much. I had a trickle charged battery powering a ten watt FM rig for ten meters when the sunspots were high... that was a great way to get on the air, I could come home from work, work some dx with great sounding FM audio, the wife could enjoy the conversations in the background, and basically I don't ever recall the little 10AH battery going too low on me. I'll make the same setup here at the new QTH but with a solar panel, should be fun. Basically people don't have to do all the calculations if they start out with a low power rig, just build it and add panels as needed... you want to determine first the smallest battery that will serve your needs, that will minimize your panel costs....
 
RE: Relatively Easy Solar Power  
by WI7B on April 4, 2009 Mail this to a friend!

Boy-howdee, thanX OMs!

I guess another deficit in my writing. The 20V no-load comment means when the PV panel is NOT connected to anything but a DVM. I thought that would have been clear.

When it's connected to the battery with the battery's internal resistance, that drops to normal trickle charge potential. The highest voltage I have every seen when the PV panel was connected to the battery is ~13.2V.

This solar panel was designed to trickle-charge a 12V battery. Honest.

73,

---* Ken
 
RE: Relatively Easy Solar Power  
by K7AAT on April 4, 2009 Mail this to a friend!

Wow - there is a lot of mis-information or misunderstanding of solar charging system on this thread.

One guy says you need to use a regulator. Under most circumstances, this would be true, but your 15W solar panel is unlikely to even raise the voltage to a dangerous level on a 33Ah battery... at best its probably putting a one amp charge out for less than 8 hours a day.... one amp at even a full 24 hours charge is about three percent of battery capacity... plus, I assume you are running some ham gear, at least in receive. If so, your solar panel isn't even keeping up with the receive current draw on most HF receivers I can think of, let alone putting a charge on the battery.

Another guy suggests my comment about not needing a diode in the line is necessary... he said if you don't have a diode in it the battery will discharge back through the solar panel. This is patently false. The solar array of diodes is not reversed from the charge current.... I've run numerous systems with no blocking diode in the charging line and never had a problem with even the slightest battery back discharge at night through the panel. I have, however, suffered massive battery bank failure when a short circuit occurred in a charging line between the battery and the panels, which is why I recommended you at least fuse the hot lead. Don't misunderstand my opinion here... a diode is a nice feature, but just un-necessary if you are running such a minimal system and you want to maximize what little you have available. Losing an additional 0.7V accross the diode is just going to shorten the amount of time your panel is able to put a charge on the battery during early and evening hours.

Take what you read here with care.... there is some incorrect understanding and responses popping up .

73 de Ed
 
RE: Relatively Easy Solar Power  
by N6AJR on April 4, 2009 Mail this to a friend!
true, google homebrew sol;ar power and look for some more info
 
RE: Relatively Easy Solar Power  
by KC9OXY on April 4, 2009 Mail this to a friend!
Oh I love it how everyone needs to de-bunk everything that is ever written here!
Good article for people, like me, who don't know anything about solar power.
 
Relatively Easy Solar Power  
by KB5ZXM on April 4, 2009 Mail this to a friend!
I was thinking that surplus out put from a solar panel could be dissipated by running a cooling fan, or two.
We do not have reliable wind energy here, but when storms come we do, and that's when we lose the civilian power grid.
I would like to see more from ppl who have home brewed. wind generation.
I also saw a portable DC generator built from a vertical, shaft gas powered push mower and a Auto mobile alternator,. I do not know how they compensated the fly wheel counter balance problem with out a blade on it.
It looked simple and was portable <pushable> and had room for one deep cycle battery behind the engine between the back wheels.
 
RE: Relatively Easy Solar Power  
by K5END on April 4, 2009 Mail this to a friend!
"Oh I love it how everyone needs to de-bunk everything that is ever written here!"

Yeah.

It's sad, really.

Some people who have no life sit at home all the time, in front of the computer, bitter, old, lonely, disaffected, angry, ignorant and stupid, with nothing better to do than expose their own ignorance by criticizing the work of others.

Any moron can be an "expert" on the internet.

Some experts have had UFOs visit their neighborhood, and appear to have been used by aliens for brain experiments.

And like aliens built the pyramids, in like manner have built "expert" websites.

:-)


 
RE: Relatively Easy Solar Power  
by AB7E on April 5, 2009 Mail this to a friend!

K7AAT,

Solar cells are massively parallel semiconductor junctions and are probably the leakiest "diode" worthy of the name you will ever find, which is the reason why silicon diodes are used in series to minimize battery discharge back through the solar cell.

What does your VOM tell you the leakage current is through your cell with 12 volts on it in the dark?

And are you sure that your panel doesn't include it''s own series diode embedded in the frame or sealed in the cable? Many do.
 
Relatively Easy Solar Power  
by N7BUI on April 5, 2009 Mail this to a friend!
Harbor Freight has a 45 watt system (three 15 watt panels) with charge controller and 12 volt fluorescent lights on sale for $199. This even includes the mounting rack! These are rated very conservatively and I've measured 50 watt output on mine. I have two of the systems in place attached directly to two 12 deep cycle batteries. This powers two radio's and provides lighting for a several days of operating without sun. The system recharges completely in a single day of sunlight.

The panels seem to be very well built and are well worth the money.

www.harborfreight.com
 
RE: Relatively Easy Solar Power  
by AD7DB on April 5, 2009 Mail this to a friend!
Watch out for the voltage drop when transmitting.
If it falls below about 11 volts, most radios will turn off.

My brother and I have run my Icom 706 from his trailer many times while dry camping. Found that the deep cycle battery (which is charged by two solar panels - I don't know their rating offhand) wasn't quite up to the job of a 20A draw on transmit. Had to reduce power to 50 watts (which still allowed a lot of contacts). We later fixed this by adding a second battery in parallel, and by running heavier gauge wire from them to the radio table to reduce the voltage drop from that. E=I*R, and thin wire has enough R to be a nuisance. No problems since.

This system also runs lights, water pump motor, and other duties. Our radio operating was at night. When we had commercial power available at a campground, naturally we used a regular power supply and plugged it into the AC outlet.
 
RE: Relatively Easy Solar Power  
by AA4PB on April 5, 2009 Mail this to a friend!
Any moron can be an "expert" on the internet.
----------------------------------------------------
Proven by some of the articles written here :-) I guess some people would rather use mis-information than to have anyone question anything in an article.

A bit of Ohm's law will show you that if the panel can deliver 15W and the battery is limiting voltage to 12V then the battery is receiving a constant 1.25A of charge. If the battery's self discharge current is lower than that then it will eventually be overcharged. I still maintain that it is always better to use a charge controller. The smaller the battery capacity and the larger the solar panel capacity, the more important this is. I meany you've already got probably $200 invested in this lash-up so why not another $30 or so for a charge controller to protect that investment?

 
RE: Relatively Easy Solar Power  
by VK4TJF on April 5, 2009 Mail this to a friend!
I belong to the Redcliffe and Districts radio club sunny Queensland Australia. During our last field day instead of using a big generator we use 200 Amp hour batteries Sealed Lead Acid type and trickel charged them with a couple solar panels. Just check out what VK5SW does at www.VK5SW.com
 
Relatively Easy Solar Power  
by KD4LLA on April 5, 2009 Mail this to a friend!
"Oh I love it how everyone needs to de-bunk everything that is ever written here!" I do not see it as de-bunking. What I read from other magazines and papers was that a charge controller "should" be used. If someone does not want to build or buy one is up to them. What I have has worked for me for five years (60 watt panel/charge controller/deep cycle battery).

Mike
 
RE: Relatively Easy Solar Power  
by KA1MDA on April 5, 2009 Mail this to a friend!
One thing that needs to be clarified here is that the user(who probably doesn't even realize it)is not getting anywhere near 15W from this panel! Here's why:

A PV panel is a CONSTANT CURRENT device. It will put out the same amount of current regardless of whether the output voltage is loaded down to 10 volts by a dead battery or floating at 14 volts on a fully charged battery. Most panels are designed to output approximately 17-20 volts open circuit. The panel capacity is calculated by the manufacturer bases on maximum CURRENT PRODUCED X NOMINAL VOLTAGE. The panel's advertised 15W rating is calculated by the manufacturer at the panel's nominal 17 volt output- which would mean the current capability of the panel is about 882 mA.

Now what happens when the panel is connected to a battery? If the battery is fully charged the panel's output voltage is loaded down to 14 volts. Since it is a constant current device, it is still delivering 882 mA to the battery. 14V X .882mA = 12.3 W. If the battery is in a highly discharged state, the panel ouput voltage will be loaded down to 11 volts. Again, 11V X .882mA = 9.7 W. So although this panel as rated as a 15 watt panel, in reality, it is only producing between 9.7 and 12.3 watts, (64% - 82% of its rating) based on battery condition.

Although the difference doesn't sound like much, it must be included in calculations for sizing battery and panel capacity. This situation could be avoided entirely if the correct charge controller were used with the panel. Controllers using MPPT (maximum power point tracking) technology utilize an inverter that can be thought of as a transformer with an infinitely variable ratio. Such an inverter (as part of an MPPT charge controller) is capable of increasing the current from the panel while decreasing the panel's output voltage to more closely match the load. Such a controller would allow the battery to receive the panel's full 15 watt output, regardless of battery condition or voltage.

Tom, KA1MDA
 
RE: Relatively Easy Solar Power  
by K5END on April 5, 2009 Mail this to a friend!
" I guess some people would rather use mis-information than to have anyone question anything in an article."

The ironic flip side to that coin is that the uninformed are FAR more likely to denigrate valid information than the informed are to point out what is wrong with the popular myths.

I guess the reason is, many of those who really know what they are talking about are also smart enough to realize it's a waste of time to argue with fools, of which the internet provides an infinite source.

:-)
 
RE: Relatively Easy Solar Power  
by K7AAT on April 5, 2009 Mail this to a friend!

A comment intended primarily to WI7B, the thread's author:

I offer my apologies for posting incorrect information. Despite my decades of experience where no diode we used between a solar panel and the battery, I was in error in suggesting you don't need a diode. I just reviewed solar cell topology and realize that when no light is on the cell ( night) the solar cell 'diode' appears to be forward biased by the battery... which could lead to a battery discharge.

I assume the reason I never saw such a discharge is because each solar cell diode only puts out about 1/2 volt, and to design a solar panel that puts out about 20 volts, a series of around 40 solar cells is needed to get that voltage. A 12 volt battery can not forward bias a series of over about 30 cells, so little or no current actually back flows through the solar panel at night from the battery.

Again, my apologies to WI7B and other for stating that a blocking diode need not be used.

Ed K7AAT



 
blocking diode  
by K5END on April 5, 2009 Mail this to a friend!
I'm curious whether a low-current, NO relay might be a good way to isolate the solar cell from the battery when the light is too low to be useful.

It would use a small amount of power, no doubt, but it also eliminates the voltage drop and any other diode related issues.

I see at least two different ways to do this, but I generally try to avoid re-inventing wheels.

Anyone tried this?
 
RE: blocking diode  
by N2EY on April 5, 2009 Mail this to a friend!
K5END: "whether a low-current, NO relay might be a good way to isolate the solar cell from the battery when the light is too low to be useful."

Yes, it could; this method was used in cars back when they used generators rather than alternators.

In those days, a typical car generator had a "regulator" with several (usually 3) relays in it. The relays isolated the generator armature and field from the battery at low RPM or when the engine wasn't running, and cut down the charge rate when the system voltage exceeded a certain value, to prevent overcharging the battery. It was done with relays because inexpensive high-current solid-state diodes and transistors hadn't been invented yet. I don't know how much power such a system would use, but I suspect that for a relatively-small setup it wouldn't save much power, if any.

If the 0.7 volt diode drop in a conventional silicon diode is a concern, and you don't want to use an inverter-type regulator, there are special low-voltage-drop Schottky diodes that can be used which have about 0.3 volt forward drop.

73 de Jim, N2EY
 
RE: blocking diode  
by AC7CW on April 5, 2009 Mail this to a friend!
"Some people who have no life sit at home all the time, in front of the computer, bitter, old, lonely, disaffected, angry, ignorant and stupid, with nothing better to do than expose their own ignorance by criticizing the work of others. "

Old?? Watch it there buddy !! I know some fairly young hams that aren't old or lonely, but they are still highly opinionated and oftentimes wrong...

Anyhow, I laid out the way forward for everybody, just because I'm an electrical engineer doesn't mean the answer has to be complicated, quite the opposite... 1) get a low power rig on rx and tx or get whatever you want, starting with a low power radio will reduce the cost and still be a lot of fun imo 2) figure out the smallest battery you are happy with, this will depend on your hours of operation and your ratio of tx to rx time 3) hook up a panel that should be enough to support what you want the battery to do and see how it goes 4) if you need more charge, add a panel...

It can be most satisfying to build something while your are learning the theoretical aspect of something, sitting around arguing theory is just "Bench Racing", all you guys that race cars know what I'm talking about..
 
RE: Relatively Easy Solar Power  
by W2RI on April 5, 2009 Mail this to a friend!
N2EY said "The system described, in a location with about 5 hours of sun per day, probably gives about 20 kWh of usable electricity per year. And it cost about $200.
If you pay 20 cents per kWh, that's $4 return on a $200 investment - ROI of 2%."

Jim, you made the mistake of assuming that the PV system only generates power for one year. To calculate the ROI properly, one would need to calculate an IRR or NPV assuming (say) a 30 year production life.
But heck, as a back of the envelope calculation let's assume that on a PV basis there's a multiplier of 10. That would boost the ROI to 20%. Not bad ! Plus, it's relatively environmentally friendly.
 
RE: Relatively Easy Solar Power  
by W2RI on April 5, 2009 Mail this to a friend!
Oops. mea culpa. What was I thinking ?
Jim was talking about an annual return and, of course, he's correct.
My bad.
 
Old?  
by K5END on April 5, 2009 Mail this to a friend!

"Old?? Watch it there buddy !!"



You're right. "Old" is NOT a bad thing.

Deepest apologies.

In fact, I want to get as old as possible!!

:-)
 
Relatively Easy Solar Power  
by HFRF on April 5, 2009 Mail this to a friend!
Every now and then I get the urge to go somwhere and buy some solar cells. But I always in the nick of time get reminded by articles like this one how little power is provided by relatively expensive solar cells. This article convices me how useless small solar farms are. When the power goes out here I want to get my servers running, airconditioner, tv, lights, and everything else going. Solar cells aren't going to cut it but my generators can. My radios are the last items I care about getting to work in a power outage.
 
Relatively Easy Solar Power  
by KG4DQJ on April 5, 2009 Mail this to a friend!
Great article!

Harbor Freight has a solar panel system that provides 45 Watts for only $199! The one I saw at my local store also included a charge controller!

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90599

73

Tom / NU9R
 
Relatively Easy Solar Power  
by KX0R on April 5, 2009 Mail this to a friend!
This is a really interesting thread - I enjoyed reading many of the comments.

Using the Schottky diode is a great idea, and these are available with ratings that will handle the voltages and currents for the moderate-sized panels we're talking about for FD and such. Cheap insurance.

Many years ago I bought a surplus PV panel that was used in a California power project. It puts out about 2.2A in full sun here in Colorado. A couple of things I learned about these panels:

They work best when cold. The output voltage drops as they get warm. You might lose a volt or two, comparing a sunny winter day to a hot summer day, with the panel correctly oriented for maximum output. My panel puts out over 17V when cold, maybe 15V hot, so it's sized about right for direct charging a "12V" battery. Many of the sealed lead-acid batteries end up at almost 15V when charged, so lots of times the combination is OK for temporary summer use with no charge controller. If you don't use a controller, you need to monitor voltage to make sure you don't overcharge.

If you install the system more permanently, a charge controller will track your battery and maximize the power saved, while protecting the battery from overcharge.

During one particularly sunny FD afternoon several years ago, I found myself with well over 15V - I had to disconnect. I was running QRP and couldn't use the energy when it was available, and I had no way to store it all.

If you mount your panel(s) with 30-60-90 degree triangles on each end, you can maximize your output by re-orienting the panel(s) - the angles help get the right tilt for morning, afternoon, etc. You can beat what you would get with a fixed mount on your roof.

Operating FD from a quiet site is so cool that once you do it, it's the only thing you may settle for. One year I set up on a table outdoors in the pine woods, and I brought along a decent speaker so I didn't need phones all the time. I could hear the stations even 100 feet away when I took breaks, etc. It was cool to hear it running on the sun.

Receive drain is a big factor to consider. An FT-817 draws about 420 mA when listening - and over 2A transmitting. With QRP we usually don't transmit as much as we listen , so the receive power is a big chunk of the budget. I got a K3, and it draws over 800 mA when receiving - so I'll need to take my 25W panel to FD this year so I can have enough energy to run the new radio.

Running QRP with solar is pretty easy and affordable. If you want 100W and plan to run a serious operation, it's more of a challenge - as others have said here already - but many people do it every year. Remember that FD batteries don't have to be solar charged during the actual event - they can be solar charged at home, over a longer period before FD, to qualify for the extra points and to make things easier. Taking several charged batteries to FD may be easier than taking a lot of large, fragile, expensive panels.
 
Relatively Easy Solar Power  
by K4RAF on April 6, 2009 Mail this to a friend!
Where's the charge controller?

After 30 days or so, you're cooking a meatloaf...

Raf
 
RE: Relatively Easy Solar Power  
by AD5KL on April 6, 2009 Mail this to a friend!
I have a Kyocera 85 watt panel (with blocking diode built-in) going to a Morningstar PS-30M controller and an 80 AH Werker AGM battery. It is very well fused & works like a charm with my FT-817 HF and TMV7 dual bander. I also run a 12 volt desk lamp, and have a lighter socket to charge my cellphone, Ipod or GPS. I can also plug in a small 12v light & put it in the hallway when the power goes out - beats candlelight.

I ran a 33 AH battery with a panel like yours & a small Sunsei controller for a couple of years and it served me well considering I only run my radios at home a couple of hours 2 days a week at best. If you do get a new controller be sure to get one with a LVD (Low Voltage Disconnect) so the circuit to your radios will go off if your battery reaches 11.4 volts or so. This will prevent deep battery discharge & will extend the life of your battery & radio. This is even more important with smaller batteries since they are depleted more quickly.

You can easily expand if needed, get another panel or battery in parallel to double your capacity as funds permit. I got a subscription to Home Power magazine (or you can read it online only & cheaper) and there is a lot of good solar info there. Granted you're not going to save a fortune on your light bill but if you enjoy experimenting with solar like I do, that's all that matters. Have fun experimenting but I warn it is addictive.

Here's mine - I need to update the site with my new controller & battery but this should give you some ideas. http://www.lancesanders.com/solar.htm
 
RE: Relatively Easy Solar Power  
by K5END on April 6, 2009 Mail this to a friend!
Something wrong with meatloaf?

It's better than fish sticks.
 
Relatively Easy Solar Power  
by WI7B on April 6, 2009 Mail this to a friend!

Well here's an example of where the author learns something from the readers and admits it!

I just got back from the Harbor Freigth store with another 45W of solar pannels and charge controller ($199 total); hooked them up to the controller and reading over 16V open circuit. I can't mount them on the roof, so these 3 panels are inside the glass balcony glass doors, pointing West. Works OK. I know its not optimized, but that's the way it is OMs. Can use them for FD easily. I'm buying another AGM battery tomorrow and connecting it all together.

73,

---* Ken
 
RE: Relatively Easy Solar Power  
by KD8FJH on April 7, 2009 Mail this to a friend!
One comment about the harbor freight 45W system:

If at all possible - replace the "charge controller" with a real charge controller. The one provided is barely more than a couple blocking diodes, a couple voltage regulators (but only for the load outputs not the battery charge section), and a bargraph led ladder meter. It will not terminate charge when the battery is full.

In other words, the provided "controller" can overcharge a battery. Use caution, or replace it with a better unit.
 
RE: Relatively Easy Solar Power  
by WI7B on April 7, 2009 Mail this to a friend!

Hmmm. The charge controller than came with my 45W setup doesn't have an LED bargraph, but an actually voltage read-out. It provides both over-discharge ( battery below 11V) and overcharge ( battery above 14.5V) protection.

73,

---* Ken
 
RE: Relatively Easy Solar Power  
by W5ESE on April 7, 2009 Mail this to a friend!
Nice article; thanks to the author for posting it.

Solar power can be quite cheap (and fun) to
experiment with, if you enjoy QRP operating.

I use simple, analog QRP rigs, like the Small Wonder
Labs SW+, Ten-Tec TKIT 1300 series QRP rigs, and
the MFJ Cub 93xx series rigs. These radios draw less
than 35 mA when receiving (the SW+ actually only
draws about 15 mA when receiving).

I have a 12V 7 AH gel cell I picked up for $5 at a
swapfest, and a 2.2 AH cell I got for free from a
local hospital (they get pulled from medical
instruments on a fixed schedule, but still have a
lot of useful life). I charge it up with a $12
solar panel from Harbor Freight.

The 7 AH gel cell has enough capacity to run a
simple analog QRP rig for a whole Field Day.

73
Scott
W5ESE
 
RE: Relatively Easy Solar Power  
by W9WHE-II on April 7, 2009 Mail this to a friend!
Given that his majesty Barack Hussein Obama, has stated that he intends to "bankrupt" coal electricity providers (HALF of the electricity in Illinois comes from coal) hams in Illinois will need this knowlege to run our lights!
 
Relatively Easy Solar Power  
by WD6S on April 7, 2009 Mail this to a friend!
In March 2009 I purchased a 4-panel 60 watt solar kit at Costco for $299. It included the charge controller, a frame for the panels, and an inverter. I got a Costco deep cycle battery ($60), a battery case ($15) from Walmart, some 6 gauge wire ($10) from Home Depot, and connected a Rigrunner 12 position distribution panel ($125). So for about $500, I have an all new solar power system. Admittedly I use the radio(s) 3-4 days a week for a few hours at a time, and I do live in inland San Diego Country where we get a lot of sun, but I have had no problem with the battery being discharged. I checked Sunday and it was at 13.61 volts after a couple hours of use.

I currently have an ICOM 756 Pro III, ICOM 7000, plus 5 VHF/UHF radios connected, and I have had them all turned on (though transmitting on only one).

Bob
 
Relatively Easy Solar Power  
by N6JSX on April 8, 2009 Mail this to a friend!
I seem to have an every other year car battery issue, requiring (~$90) replacement with new every other year. I've now pushed this out beyond two years.

I'm sure my IC2800 50W 2m/440 rig, IC7000 100W rig w/screwdriver controller, GPS, Cellphone charger has something to do with extra battery strain. Plus the various 12V plug-in cords have LED indicators.

I solved this with buying an automotive plug-in 1.5W 12VDC solar cell charger ~$15.00. But I swiftly discovered a serious problem with this cheap buy....
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=44768

The housing plastics melts in direct sunlight. I removed the glass solar cell from the big plastic housing - glued the cord to the cell, added Velcro double stick beneath and placed it comfortably on my passengers top dash. It is plugged in 24/7 and has exhibited very good trickle charging - negating the LED indicator/BU memory drains from the battery system.
 
RE: Relatively Easy Solar Power  
by K4RAF on April 8, 2009 Mail this to a friend!
Xantrex Makes Very Good Controllers. Well Worth the Money & Extends Battery Life!!!
 
Relatively Easy Solar Power  
by W0FAA on April 9, 2009 Mail this to a friend!
NorthernTool.com, formerly Northern Hydraulics, has a nice 60 watt unit with solar charge controller and inverter for about $350 that I have been using.

The engineers will optimize and argue the fine points, I enjoy reading it, but don't let it stop you from putting together a "good enough" system. Avoid big mistakes if you can and don't sweat the small stuff. I try to stay well away from "the point of diminishing returns"!

JJ
 
Relatively Easy Solar Power  
by N6JSX on April 9, 2009 Mail this to a friend!
If we are just using 12VDC then our life is easy. but if you need 120VAC from 12VDC the inverter/converters at any reasonable wattage (>1200W) is very costly.

Then add to this the power controllers to properly charge the 12VDC battery as well as solar-cells/wind-generator get nearly prohibitive on our meager budgets.

Has someone done a costing to 12VDC 100W SSB & 50W FM transceivers (normal OPs over 30 day period [~15hrs RX and 3hrs TX]) to understand how long it will take to get to the alternate power source break even date or get to the cost-in-investment payback? Then add to this over 15yrs the costs of maintennce (battery replacement). Now add to this your shack lighting, computer, internet modem/network, and environment power that are normally VAC.

Other than for emergency power is it really worth all the cost/effort to say "I'm GREEN"?
 
RE: Relatively Easy Solar Power  
by N2EY on April 9, 2009 Mail this to a friend!
N6JSX asks: "Has someone done a costing to 12VDC 100W SSB & 50W FM transceivers (normal OPs over 30 day period [~15hrs RX and 3hrs TX]) to understand how long it will take to get to the alternate power source break even date or get to the cost-in-investment payback?"

Those calculations are not difficult. Here's an example of how to do them.

First, you put together a system and see what it costs. For purposes of illustration, suppose we have a system that costs $200 and produces 10 watts of usable electricity in full sun. (by "usable electricity" I mean actually delivered to the load, after accounting for the losses in the regulator, battery, etc. )

Suppose that system is installed in a location that gets, on average, the equivalent of 6 hours of "full sun" sunlight per day.

We can then figure how much energy we'll get from the system per year: 365 X 6 = 2190 hours per year. Say 2200 to keep the math simple.

2200 hours per year times 10 watts = 22,000 watt-hours per year, or 22 kilowatt hours per year.

The price of electricity varies widely, depending on where you live. In some places a kilowatt hour costs almost 20 cents, in others it's about 5 cents.

Suppose the system described as an example is located in a high-cost place, where electricity is 20 cents per kilowatt hour when you consider the efficiency of a 12 volt power supply. Then that 22 kilowatt hours of energy would cost $4.40.

For a simple calculation, divide the $200 system cost by $4.40 and you'll see that it will take 45 years (!) to break even - assuming the system lasts that long without needing any new parts. In real life, it's a safe bet that the batteries will need replacing at some point, and that the panel and regulator will not last forever. Depending on how long the components last and how much replacements cost, break-even may never be reached if all else remains unchanged.

The situation is even worse in places where electricity is cheaper, or where the sun shines less. In some situations (more sun plus higher electricity cost) the situation may be a better. But we're still talking decades.

And there's always the question of what else you could do with the money. For example, if you put $200 in a bond that earns 2.5% interest, you'll make $5 per year (before taxes....). If you replace an inefficient user of electricity (say, an old refrigerator or air conditioner) with an efficient one, or do energy-saving improvements such as insulation, better windows, weatherstripping, or just turning stuff off when not in use, your payback time may be much shorter.

HOWEVER, that's not the whole story.

First off is the question of what utility rates will do in the future. It's a safe bet that they will rise, so the payback picture may be very different over the life of the system.

Second is the question of whether you can avoid buying something by installing a PV system. For example, if the installation of the above $200 system means you don't have to buy a $100 power supply for the shack, the actual cost of the system is $100 rather than $200, and the payback time is cut in half.

Third is the value of having an electricity source independent of the local utility. If your electricity supply is highly reliable, such a system may not be worth much to you, but if you experience frequent outages it may be worth the money. Yes, you'll get more watts-per-dollar from a generator, but those things consume lots of fuel and need maintenance and repair. And they only work as long as you have fuel for them.

Fourth is the fun/education factor. The author of this article may not have made a drastic reduction in his electric bill, and his system may never pay for itself in the classic accounting sense. But I bet he had fun installing and using it, and has learned a lot in the process.

Pure cost comparison is fine if that's the only criteria, but it's a bit like the person who goes fishing for sport and computes the total cost-per-pound of the fish caught based on the cost of the tackle, boat, license fee, travel, clothing, etc. compared to the cost of store-bought fish.

73 de Jim, N2EY
 
RE: Relatively Easy Solar Power  
by N6JSX on April 10, 2009 Mail this to a friend!
Jim, the magic of numbers can always be deceptive - there are to many variables that need to be set to get any meaningful figures/dates/costs. But what I raise is the other side - that of "practicality" and "return-on-investment", not the intellectual self eduction or the FADE of being able to say "I'm GREEN" in my OPs.

Such as your $200 for a system is really more like $1000 if a charge controller and VAC converter is used (this does not include battery maintenance) and that may not create enough power to support your radio operating style (another variable). What if you need two deep cell batteries for the extra current needed? Then you need an isolator between the batteries or a specialized charge controller (for two/more batteries). I can compute a reasonable forecast with the break-even point - but can non-engineer HAMs?

So HAMs need to step into this project with their eyes wide open. Solar cells make good keep-alive chargers (as motorhome users have known for years) but will never be adequate, at a reasonable price, as the sole battery system charger.

I have nothing against be "prepared" been harping this to HAMdom for years. Search for my FD "Class G" article. Isn't that one of the goals for ARRL FD? To bring awareness to emergency communications "needs" and your preparation to support those needs? Wait guys this was rhetorical questions; I know this questions one of the holy of holy shrines of HAMdom the entity that is never wrong (only $elf $erving)- ARRL.

Just some leading thoughts for all to ponder before spending and disappointment..... Kuby, N6JSX, MS-EET
 
RE: Relatively Easy Solar Power  
by N6JSX on April 10, 2009 Mail this to a friend!
Oh and another point that I forgot.... BEWARE of non-gel cell batteries in an enclosed room/house. While charging acid batteries out-gas dangerous and CORROSIVE poisonous gas!

This leads to another big cost gel-cell vs acid batteries?

If you want the easier/cheaper acid deep-cycles putting them in the garage for safety; what will the 12VDC drop be to your shack location when running FM 100W TX (worst case)? Start thinking of 00/000/0000AWG welding cable that is at least $2/foot (copper ain't cheap) to minimize the resistance/drop in the wire to high current draws. How many feet away? Now double this cost for a (red)positive and a (black)negative cables.

You could think octopling up 8AWG cables but that becomes more costly and hard to physically manage - beyond unsightly, think XYL.

 
RE: Relatively Easy Solar Power  
by WI7B on April 10, 2009 Mail this to a friend!

A couple short comments:

(1) Neither a gel-cell or traditional SLA battery. What I used - if you perused my article - was an AGM SLA with nearly 99% coversion of emitted gas back to water and little potential for leaking. I think you are dealing with some old technology, OM.

"Oh and another point that I forgot.... BEWARE of non-gel cell batteries in an enclosed room/house. While charging acid batteries out-gas dangerous and CORROSIVE poisonous gas!" - N6JSX


(2) Well, I never have claimed to be "GREEN" except on St. Patrick's Day, but I was schooled in the Chicago Palatinate so that goes with the turf (no pun intended). However, in calculating the needs of my station with this small solar project it made me aware of ALL my energy usage. This is a very enlightening prespective. It made me aware of areas of the household where energy was not being efficienty employed. As a result, I changed or curbed some of the wasteful practices of everyday life.
I haven't lost much, if any, quality-of-life from changing my energy usage, but I have saved energy. So, while my little solar project is not cost-effective in and of itself, the knowledge gained by carrying it out HAS been cost-effective.

"Other than for emergency power is it really worth all the cost/effort to say "I'm GREEN"?" - N6JSX


73,

---* Ken



 
RE: Relatively Easy Solar Power  
by WA4DOU on April 11, 2009 Mail this to a friend!
I've been quite interested in solar power for about 30 years. I have a 14 volt 200 ma panel that is now about 27 years old ($18 per watt) and a 14 volt 1.6 amp panel that is 15-20 years old. I bought it used in the early to mid '90s around $6 per watt. It started life as a 4 amp panel and was part of a solar power experiment out west that had 20 suns focused on it (mirrors). After reading this article, I found myself wondering what panels cost these days. I was surprised and quite pleased to see that they've dropped into the $2.50-$4.00 per watt range, new. That's really quite exciting. I think solar power is on the verge of taking off in a big way now.
 
RE: Relatively Easy Solar Power  
by N2EY on April 11, 2009 Mail this to a friend!
N6JSX writes: "If you want the easier/cheaper acid deep-cycles putting them in the garage for safety; what will the 12VDC drop be to your shack location when running FM 100W TX (worst case)?"

That depends entirely on the distance, the current demand, and the allowable voltage drop.

N6JSX: "Start thinking of 00/000/0000AWG welding cable"

Let's do the math!

Say the distance is 50 feet and the rig draws 20 amps. That's 100 feet round-trip. Let's also say that the maximum allowable voltage drop is half a volt (0.5 volt).

Then the total resistance from batteries to rig must be kept to less than 0.025 ohm (0.5 divided by 20)

Since we have a 100 foot round-trip, we need wire that has resistance of no more than 0.25 ohms per 1000 feet. #4 is almost good enough (0.2533 ohms/1000 feet)
but you really need #3 to be sure (0.2009 ohms/1000 feet). Since #3 is an odd size, #2 is probably what you'd wind up using (0.1593 ohms/1000 feet).

To reduce cost, consider using aluminum, which costs less in big sizes (which is why it's used for service entrance cable). Of course since the resistance of aluminum is higher, you'll probably need heavier stuff.

N6JSX: "You could think octopling up 8AWG cables but that becomes more costly and hard to physically manage - beyond unsightly, think XYL."

Four #8 is the same as one #2. Doesn't need to be unsightly if it's done right.

None of the above is complicated or even first-year engineering-school stuff; it's just Ohm's Law for DC and some knowledge of the issues.

The big issue, though, is total system design. For example, is 100W FM really needed, or would 25 or 50 W be enough? Can batteries such as the original author's AGM type be used, which reduces the acid and hydrogen issues? What's the real-world average daily sunlight at the location?


73 de Jim, N2EY
 
RE: Relatively Easy Solar Power and an OT issue  
by N2EY on April 11, 2009 Mail this to a friend!
N6JSX writes: "Jim, the magic of numbers can always be deceptive - there are to many variables that need to be set to get any meaningful figures/dates/costs."

You're preaching to the choir on that one!

N6JSX: "But what I raise is the other side - that of "practicality" and "return-on-investment", not the intellectual self eduction or the FADE of being able to say "I'm GREEN" in my OPs."

I'm not sure what you mean by "intellectual self eduction" or "FADE" in this context.

N6JSX: "Such as your $200 for a system is really more like $1000 if a charge controller and VAC converter is used (this does not include battery maintenance) and that may not create enough power to support your radio operating style (another variable)."

My point in the earlier post was not to design a specific system but to demonstrate the issues surrounding a practical design. The hypothetical $200 system I described would include a panel, controller and battery, but assumes the resourceful radio amateur can come up with cables, connectors, mounting hardware and similar doo-dads from the junk box or at nominal cost. It also assumes that the rig will run off 12-14 volts DC, and not need 120 VAC, and that the ham will do all the work for nothing.

As I demonstrated, such a system delivers a relatively small return on investment, even in high-electricity-cost/lots-of-sun areas, and even if everything lasts 20+ years.

N6JSX: "What if you need two deep cell batteries for the extra current needed?"

You don't do it that way. You get a bigger battery from the get-go. Or individual cells. Personally, if it were my installation, I'd have a nice bank of wet-cell nicads. Couple of hundred AH at least, with panels to match. But that's big-bucks stuff.

N6JSX: "I can compute a reasonable forecast with the break-even point - but can non-engineer HAMs?"

Sure they can - if the issues are brought up in a reasonable and understandable manner. None of this is really complicated nor even at the first-year engineering school level, but it *is* stuff we hams ought to know.

IMHO, the real point of the whole exercise is for hams to become more educated on the issues surrounding energy supply, be it from a utility, solar, wind, generators or whatever. Isn't that sort of education a big part of what Amateur Radio is all about?

How many Americans can tell you the difference between a kilowatt and a kilowatt-hour? How many can tell you how much they pay for a residential kilowatt-hour from their local utility?

N6JSX: "So HAMs need to step into this project with their eyes wide open."

Agreed - but that doesn't mean they shouldn't at least try *something*.

That's the real beauty of the original article: the author wasn't trying to design a system that would power his entire shack, or home. He simply assembled a basic system to try out solar power on a small scale. What he got seems to do the job he wants it to do. And we've all learned something in the process.

N6JSX: "Solar cells make good keep-alive chargers (as motorhome users have known for years) but will never be adequate, at a reasonable price, as the sole battery system charger."

Sorry, you don't know that to be true. Such a prediction is unnecessarily pessimistic.

Right now, solar-electric technology is simply not cost-competitive with utility-supplied electricity in most cases. The exceptions are when the cost of connection to the utility is prohibitive/just plain impossible, or when you only need a little bit of electricity and the utility has a big minimum charge per month just to be connected.

But the cost-competitive situation may change as electricity costs rise and solar-electric costs drop, and new technologies are developed.

N6JSX: "Isn't that one of the goals for ARRL FD? To bring awareness to emergency communications "needs" and your preparation to support those needs?"

Yes, it's ONE of the goals of Field Day. But not the only goal; FD is a lot of different things. IMHO, that it simply gets a lot of hams outdoors and makes them think about such issues is a good thing.

OT question: Why do you capitalize all the letters in "ham"? I never saw that done until a few years ago, but now it's becoming common.

73 de Jim, N2EY
 
Relatively Easy Solar Power  
by KG4RRN on April 12, 2009 Mail this to a friend!

The incorrect capitalizaton of the word "ham" started several years ago,when those obnoxious round three letter destination abbreviation stickers started to appear all over the backs of SUV's.(2001?)
For instance, everyone knows that NYC means New York City and NNJ means Northern New Jersey.
I had fun last year operating a wet cell 1000 amp capacity, battery in Field Day. I operated a 65 watt VHF and 25 watt UHF mobile on it, off and on all day. Battery voltage never got down past 12.2 volts in over 12 hrs. So that means it lost exactly a volt.
I had the battery for about a year, and loved to exercise it during thunderstorms. It recharged nicely on a 6/12 charger overnight, and only lost about 5% of value(@13.2 volts) per week.Sometimes Cadillac batteries work better than AGM types, and have staying power too.(if new).
Don't count on Solar Cells exclusively to power rigs all day, unless your operating an FT-817D at 5 watts.
Even then, Gell-cell batteries are great, don't weigh as much, and can be series fed,and trickle charged back to health.It's great that people have solar cells,
but like everything else, they will deteriorate over time, left outside.
The wiring looks dangerous....

 
RE: Relatively Easy Solar Power  
by N2EY on April 13, 2009 Mail this to a friend!
KG4RRN writes: "The incorrect capitalizaton of the word "ham" started several years ago,when those obnoxious round three letter destination abbreviation stickers started to appear all over the backs of SUV's.(2001?)"

That's as good an explanation as I've heard. But unlike those stickers, "ham" isn't an acronym for anything!

KG4RRN: "I had fun last year operating a wet cell 1000 amp capacity, battery in Field Day."

Do you mean 1000 Amp-Hour? Such cells are enormous - and heavy!

KG4RRN:"Don't count on Solar Cells exclusively to power rigs all day, unless your operating an FT-817D at 5 watts."

That depends on how many panels you have. The number of panels needed to run a 100 watt rig continuously is pretty large, though.

My back-of-the-napkin guess is that, for a 100 watt rig on Field Day, operated contest-style with no breaks, you'd need at least 200 watts of panel plus regulator, and a pretty hefty battery (over 100 AH) for the hours of darkness. That's over $1000 worth of stuff!

73 de Jim, N2EY
 
Relatively Easy Solar Power  
by N6JSX on April 13, 2009 Mail this to a friend!
N2EY is eHAM.NET your whole HAM life?

It sure seems to be, as you appear to be a technical expert/guru on "all" subjects posted on eHAM. On this subject I think I counted 10 postings from you - every posting you made appears to confirm your unique ability to read the mind/intent of the User your questioning. Your skill in belittling users with your vastly profound wisdom and insight shows a mastery of rhetorical minutia.

Do you have a "real" radio life, I get it your an electrical/electronics engineer with +30 years of extensive power/RF/digital/analog/design/manufacturing/quality experience - sorry I asked? We all bow to a master.
 
RE: Relatively Easy Solar Power  
by KB0TXC on April 13, 2009 Mail this to a friend!
N6JSX wrote:

<N2EY is eHAM.NET your whole HAM life?

It sure seems to be, as you appear to be a technical expert/guru on "all" subjects posted on eHAM. On this subject I think I counted 10 postings from you - every posting you made appears to confirm your unique ability to read the mind/intent of the User your questioning. Your skill in belittling users with your vastly profound wisdom and insight shows a mastery of rhetorical minutia.

Do you have a "real" radio life, I get it your an electrical/electronics engineer with +30 years of extensive power/RF/digital/analog/design/manufacturing/quality experience - sorry I asked? We all bow to a master.>

KB0TXC responds:

????

At least he posts! I have posted extensively in the past, but as I have been quite busy these last four or five weeks and now that my significant other has had major unexpected surgery, I have been off the forums for a bit.

Don't be mean to Jim N2EY... He is a nice guy and has been operating for many years, almost for as many years as I have been here on this earth in this incarnation.

Also miss my other friend Lenny, AF6AY. Hope he is still around as well.

Jim and Len add a great banter and spice to the forums as both are very knowledgeable in their prospective areas.

Best and 73

Joe KB0TXC
 
RE: Relatively Easy Solar Power  
by AD5KL on April 14, 2009 Mail this to a friend!
I used lighter 14 guage wire for the longer 40 foot run from the solar panel to my radio room where the AGM battery is located. Panel at most puts out 5 amps so I used lighter guage wire for the longer run. The radios can pull 20 amps on transmit, so I chose an AGM battery in the room & heavier 8 guage wire so I could keep the battery closer to the radios & cut voltage losses.

Ideally I would put a pair of golf cart batteries in a box under the house (vented to outside of course) directly under my radio room. Then short run with heavy wire from batteries to radios.
 
RE: Relatively Easy Solar Power  
by K6LHA on April 14, 2009 Mail this to a friend!
KB0TXC posted on 14 Apr 09:

N6JSX wrote: <about those who spend an inordinate amount of time writing in e-ham, main portion elided since it isn't necessary to copy so much>

"At least he posts! I have posted extensively in the past, but as I have been quite busy these last four or five weeks and now that my significant other has had major unexpected surgery, I have been off the forums for a bit."

...may your SO recover quickly and have minimal pain.

Joe, you cannot possibly approach the prodigiousness of Jimmy's output over the last dozen years. He is everywhere...
.............
KB0TXC: "Also miss my other friend Lenny, AF6AY. Hope he is still around as well."

No, my weight hasn't changed and I am not 'a round.' Joe, we aren't what I term 'friends' in the defined sense of the word. We are acquaintences on screens is all. We have some common ground on some opinions but that is that.
..............
KB0TXC: "Jim and Len add a great banter and spice to the forums as both are very knowledgeable in their prospective areas."

Impossible. As a "know-nothing newbie" to ham radio, I can't possibly KNOW anything about amateur radio, not even after 2 years and a month plus a few days of being licensed as an amateur. Amateur radio is an ENITRELY different subject than any other electronics. I am constantly "wrong," "mistaken," "a failure," etc., for various "reasons" such as not having gotten my amateur radio license FIRST (even if not at teen-age years) and then "worked up" gradually through the ranks until I approach (but can never meet) the glorious excellence of these mighty masters of morse modes who are superbly superior to all.

Other than that, I find these articles of ACTUALLY DOING SOMETHING AND REPORTING THE RESULTS most interesting. My two years plus in unmanned spacecraft fabrication in Pasadena, CA, was spent next door to another clean room where spacecraft solar panels were assembled. I did not pursue any technical inquiry on those back in the early 1960s other than what was required to interface with spacecraft electronics. It would have been nice to know some more NOW when prices have dropped and many vendors supply them. But, it is hard to look ahead in electronics over 4 decades and predict what one needs to know. [my crystal ball doesn't work although I have two functioning organic ones]

Normally I keep quiet in forums that are engaged in projects-experiments in which I've no (or very limited) experience. I save these articles up to the point they aren't available for replies. They MIGHT be useful to me later. At about 20 cents a blank CD that can hold a half-GigaByte and be added to later, it is a cheap way to store knowledge that hasn't been filtered through some new england suburb. At most I will ask questions but try to not to explode with a denigratory "you are MISTAKEN" sort of comment. There are "sensitive" olde-tymers on E-Ham who are very easily "insulted" if egregious compliments are not tendered to their majesties. <shrug>

No, I'm not contemplating any solar-electric power source at the moment. Southern California does have greater solar influx than most of the 50 states but I am such a casual user of amateur radio that I do not see any terrible need of such alternate electricity sources just for that. Home Depot. et al, carry small generator sets useful for emergency electric power, but I do not contemplate getting any in the near future. A short-term Uninterruptible Power Source for the PC is useful and I have that for the very rare commercial electric power glitch here in the southland.

Still, actual results of available solar panels are good to know. It is a much better alternative to the usual squabbling that goes on in these forums where several hurl Ohm's Law of Resistance at one another as if this were a food fight court in a junior high school...naturally, without themselves ever engaging in such ACTUAL projects. :-)

May all who post PRACTICAL ideas and application continue. Those are appreciated much more than the flying food that happens as articles whither to archival storage.

73, Len AF6AY
 
RE: Relatively Easy Solar Power  
by N2EY on April 16, 2009 Mail this to a friend!
N6JSX-

Is there anything wrong with what I have written in this thread? Did I make a math error or get any facts wrong?



73 de Jim, N2EY
 
RE: Those Terribly "insulted" Posters...  
by K6LHA on April 16, 2009 Mail this to a friend!
N6JSX posted on April 13, 2009:

"N2EY is eHAM.NET your whole HAM life?"

"It sure seems to be, as you appear to be a technical expert/guru on "all" subjects posted on eHAM. On this subject I think I counted 10 postings from you - every posting you made appears to confirm your unique ability to read the mind/intent of the User your questioning. Your skill in belittling users with your vastly profound wisdom and insight shows a mastery of rhetorical minutia."

Dale, your questions was more-or-less answered by Jimmy's response on 16 Apr 09:

N2EY: "Is there anything wrong with what I have written in this thread? Did I make a math error or get any facts wrong?"

From Jimmy's 'question' answer, he seems only interested in replying on just about everything, all the while heedless of HOW he phrases his comments and, generally, disrespecting anyone who doesn't agree with him. That was my take after some dozen years of exposure to his contentious commentary on just about anything I had to say on any subject. He MUST be "right" and will argue and argue and argue with anyone who doesn't agree with his opinions/ facts/ knowledge.

Note that you gave only your OPINION in your posting, Dale. Nothing about "math errors" or "facts." Jimmy's response is NOT concerned with your opinion of him. He may be egocentrically immune to that, thinking that only He has the lock on 'what is right' in amateur radio.
..............
N6JSX: "Do you have a "real" radio life, I get it your an electrical/electronics engineer with +30 years of extensive power/RF/digital/analog/design/manufacturing/quality experience - sorry I asked? We all bow to a master."

All anyone on any public-access forum about amateur radio 'knows' is that he has a BSEE and an MSEE, began as a Novice amateur at age 13, became an Extra at age 16, built a bunch of boxes that makes up a 40m CW tube rig that began construction around 1970, has attended every Field Day since long ago. He is extemely reticent about anything else, his employer, his family, his mate (if any), or his other pasttimes (again, if any). From being the co-inventor of record of a Patent assigned to Consolidated Railways on a railroad switching system, we know that, at one time, he DID work for 'Conrail.' He has not mentioned any detail of working for any identifiable electronics firm in the last 4 decades. Nor has he mentioned ANYTHING in regard to the work he actually does.

His 40m rig is based on some design called a "Southgate Type." No search has uncovered any origin of such a "Southgate Type" yet the word "southgate" turns up hundreds of hits. There might be some connection to the UK-based Southgate Amateur Radio Club located in a section of London. However, a search of that ARC does not turn up any "Southgate Type" anything in the way of any HF receiver/transmitter/transceiver project. He continually ignores any requests for clarification on that.

N2EY has implied a few times in the past that he is a "radio manufacturer." He has associated the "southgate" name with that "product" yet there is no Search result that comes up with any "Southgate Radio Products" company or similar. Continued mention of a "company" seems suspicious to say the least. No other "company name" has been stated. It is not possible to disprove something that does not exist, therefore some folks love to IMPLY things...but without any plausible proof that such implications are REAL and factual.
--------------
My own work experience is not remarkable but it spans the 57 years from 1952 to 2009, both professionally and as a hobbyist (hobby began in 1947 with an interet in learning about 'radio' to control model aircraft I was flying as a teenager). I can identify every single employer and name their product lines, many in great detail, but that has been rebuffed by N2EY and some others on the grounds that "it is not ham radio." <shrug?>

In the 53 years I've lived in southern California working in aerospace electronics (mostly), I've been up to above my scalp in more MIL SPECS and EIA standards and radio regulations than I care to have dpme, KNOW the electronics industry test procedures, etc., etc., collecting a mass of application notes and reference material thereto. N2EY has accused me of being "wrong" or "mistaken" in many of those. If I attempt to correct him on non-standard electronics industry nomenclature and terms. He does not accept correction well at all, yet claims to be a "working professional" in that field. I do not consider railway operation to be a part of the 'electronics industry.'

If one engages in radio communications as a hobby AWAY from regular work, I have no dispute with that. However, anyone who demands I DO CERTAIN things IN that hobby that are not defined in law, I get a bit testy with those. Jimmy writes as if he has memorized every single publication from the ARRL. Neither do I look to the entire publications output solely from the ARRL as 'THE' text references on 'radio.' There is MUCH more away from that minority association that has those references covered. The HF portion of the EM spectrum was already pioneered prior to WWII and very few around today can lay claim to 'pioneering' the 'shortwaves.' Neither do I venerate or endorse turning back time to the 1970s or earlier in order to pursue my own casual interest in amateur radio hobby activities. 'Radio' works by the SAME laws of physics regardless of MAN-MADE law defining one spectral area as 'amateur' while the larger 'other' area is for other radio services.

As to all the 'feeling insulted' by other commentors in any forum, that is usually a sign of egocentricity where the 'insulted' are so engulfed in their own 'correctness' or have the presumption that They are the ultimate role-model of What To Do (high degree of egocentricity) that they become angry at or engage in outright denigration of those who want to do as they want to...it is nonsense to ascribe individuality in likes and dislikes as some kind of idiotic "moral flaw". N2EY exhibits such feelings of 'being insulted' from time to time. Perhaps he has some form of Bipolar Disorder?

Being retired is an interesting state. I can comment - or not - at my leisure...and also check out who posts what and WHEN. It is not unusual to find that many use their computers at work to post things here if their identities are know as to residential time-zone. [using a forwarding alias to get recent postings has an automatic time-date stamp to check that, just a minute after it was posted directly on E-Ham] I don't diss those folks who take time to use work PCs for their own purposes. Neither will I give them kudos for being 'able to get away with it.'

Egocentricity has another syndrome: Air of superiority in any field being discussed. I like to be informed in areas where I've not had any (or much) experience in HANDS-ON activity. That might come in handy in the future for me. However, in other areas of electronics technology, I've accumulated some experience that MIGHT be of value to others. I will share that to anyone displaying a sincere desire for knowledge. I do NOT wish to get into contentious arguments with those who PRETEND to know everydamnthing there is about radio, then come unglued when They aren't 'respected' for Their 'vast body of knowledge' (that is only 'half-vast').

73, Len AF6AY





 
RE: Those Terribly "insulted" Posters...  
by RFSOAKED on April 22, 2009 Mail this to a friend!
I'm going to ask a related question and it doesnt have anything to do with capacity, Ah rates, etc...

Anyone that has these on their roof in the midwest, or elsewhere that sees severe weather, how do they hold up in events such as hail storms? I often thought about adding some solar power here, but after seeing golf ball and even softball size hail denting shingles and taking out windows and shattering vinyl siding on my house and neighbors houses over the years i would think its like putting an expensive target on the roof.

I can't find any specs on commonly available panels that rate their impact resistance. I saw an article online which showed one guy building them into a roof mounted box with a thick lexan cover, but that would also affect the sunlight making it to the panels as well wouldn't it?

 
RE: Lexan Covers and Hail Protection  
by K6LHA on April 23, 2009 Mail this to a friend!
Someone pseudonymed "RFSOAKED" posted on April 22, 2009:

"Anyone that has these on their roof in the midwest, or elsewhere that sees severe weather, how do they hold up in events such as hail storms? I often thought about adding some solar power here, but after seeing golf ball and even softball size hail denting shingles and taking out windows and shattering vinyl siding on my house and neighbors houses over the years i would think its like putting an expensive target on the roof."

Having spent my first 19 years growing up in northern Illinois, I've never experienced any "golf ball" and certainly not "softball size" hail...and that includes REAL golf balls on weekends at the transmitter site of WRRR, Rockford, IL (next door to a golf club).
..............
"I can't find any specs on commonly available panels that rate their impact resistance. I saw an article online which showed one guy building them into a roof mounted box with a thick lexan cover, but that would also affect the sunlight making it to the panels as well wouldn't it?"

There's all sorts of information on polymers on the web, but one has to search rather hard to get it and interpret it all. Try manufacturer's websites once you get a name for a maker of it, as in labels at do-it-yourself hardware chains.

To determine the amount of shielding of sunlight from panel covers, you need to get transmissability values in scientific terms as given by manufacturers for various thicknesses AND at the wavelengths of sunlight. Sunlight peaks about at the wavelength of yellow-green light (logical since we all evolved to survive with that 'color temperature'). Once that is done, you need to get the electrical characteristics of a solar panel in regards to light wavelength. Again, you have to get that from panel manufacturer's information.

You will be awash in a lot of scientific terms that can't be found in the ARRL Handbook. Chalk that up to just one more of life's little lesson sessions. :-)

73, Len AF6AY
 
Relatively Easy Solar Power  
by VE7OTH on April 23, 2009 Mail this to a friend!
Is this an article or is there a link in there that I'm missing... is it just super short?

73's
Jen
 
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