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Author Topic: alternate power  (Read 4557 times)

Posts: 7

« on: March 25, 2008, 02:57:56 PM »

I have a Yaesu FT2800m and am looking for a way to get power when no power is available.  I would like to run solar power but the panels are very expensive.  I want to be ready in case of a emergency.

Posts: 2415

« Reply #1 on: March 25, 2008, 11:41:48 PM »

I have found that using a marine (boat) type deep cycle 12 volt battery, Along with a 10 amp fully automatic charger works well to power my station (Charger running off commercial AC power)
(I have no "regular" AC to 12 volt power supply, The battery runs my entire hamshack. Just hook all the equipment right to the battery. Through a large fuse located right next to the battery for safety)

I suggest you set up with a similar power supply, And then add solar cells as you can afford them.
Harbor Freight Tools sometimes has sales on them.

Dont expect too much for the 12 bucks.....  I have a few of those, And they do help keep your battery charged in the event of a commercial power outage, Or for camping etc.  But those little cheap chargers put out pretty low ouput power, And really have no type of regulation, And need to be disconnected from the battery in the dark, etc.     But for low cost experimenting, Worth the price.

Like you say, High quality solar panels are very expensive. However, The cost IS still coming down, But really slowly!

(An even better choice for the battery is one of those AGM types, But new, Cost lots more than the typical 50 dollar price of a marine deep cycle type.)
Keep watching for surplus AGM type battery pull outs from commercial UPS, etc.

Posts: 229

« Reply #2 on: March 26, 2008, 02:39:10 AM »

You might consider a used UPS backup power system.
I'm using an APC SU1000 that provides both 120v AC
and 12v DC for my Icom 746 and 275H radios.
Checkout for additional info.

Posts: 297

« Reply #3 on: March 26, 2008, 06:55:08 AM »

Check Harborfreight for cheap solar panels.  I have a couple of these (5W panels, for a different project) and I have a few 1W panels (that I wired in parallel to boost the amperage) for my main station.  While you may think that 1A at 12V is not that much, don't forget that something is better than nothing.  Also, I believe that radio can be turned down to 5W.  Here are the specs for your radio:

Rx (Non-Squelched): < .7A
Rx (Squelched): < .3A
Tx (65W): 10A
Tx (25W): 7A
Tx (10W): 5A
Tx (5W): 4A

A 5W panel will give you .416A (5/12), which would be enough to cover your receive without squelch.  If you get 3x of the 5W panels (to make 15W), then you can generate 1.25A per hour.  Since most of emcomm is Rx (unless you are net control), you won't be transmitting 24/7.  A good ratio is 3:1 (Rx:Tx).  So for this radio:

Rx: 3 x .7A (non-squelched)= 2.1A
Tx: 1 x 5A (10W) = 5A

Add these together (2.1A + 5A) and you come up with around 7.1Ah.  So you will either need 7.1Ah x however many hours you want to operate or be able to generate at least 7.1Ah.  If you had the three solar panels, you would only need an additional 5.85Ah.  With this math, you can calculate roughly how much power you will need in an emergency.  If power-outages aren't that common, then you can plan for that.  If you live in a rural area and drop power on a daily basis, go for a heavier battery.

These LED lights are bright enough to light an entire room and will surely come in handy if you lose power.  Don't forget, a radio is nice to communicate, but if you can't see what you're writing, you may run into difficulty.  They are also cheaper and have more LEDs than the West Mountain Radio LED light.

I hope all of this helped.

73 de KB3LSR

Posts: 293

« Reply #4 on: March 26, 2008, 01:38:37 PM »

I'm a generator man. I have a Honda EU1000i that's perfect for Field Day-type operations. It starts every time, weighs less than a battery, IMHO requires less maintenence than a battery, and will probably last 5X longer than a battery, so it's not as expensive as it seems.

Posts: 536


« Reply #5 on: March 27, 2008, 08:04:31 AM »

You haven’t indicated as to whether you plan on this to be a portable or a fixed location installation.  Assuming portable for emergency work, you a might want to go to eBay and search on the terms "solar" and "briefcase" to find these 13 watt units which fold nicely and go for about $75 after shipping costs are included.

I use 4 of them in parallel to feed a 4-amp Micro M+ solar charge controller with a 25 AH gel cell for portable work. Lets me operate all day.   You can see a picture of my set up on the Amateur Radio Emergency Communications article of Wikipedia.

I personally prefer gel cells or AGM batteries for our purposes, but if you do decide on using a flooded (wet) cell of any type or voltage, remember that they are designed for permanent installation in a vehicle or battery coffin outside of a building. They are not designed for lugging around in portable applications because of the danger of spilling battery acid and are not to be used indoors because of the outgassing of explosive hydrogen when charging.

Avoiding these fairly serious limitations is why I prefer Gel Cells or AGM's. The extra safety and flexibility is worth the cost.


Gary, K2GW

Posts: 1042

« Reply #6 on: March 28, 2008, 05:17:49 PM »

You don't give a lot of details:

Keep in mind the below is for MY all 12 volt shack - only my PC is 120 volts AC power.

For short term outages at home, my station is powered by a 100 amp/hour AGM deep cycle battery - this is on a float charger 24/7.  Weighing about 80 lbs, it does not go far.

For longer term outages, I have a generator - usually the battery gives me a good 4-6 hours before the generator is needed.  In our area, our average outage is in the 2-4 hour range so the generator does not get lots of use.

For portable use, I have a RACES radio box with 24 amp/hours and a 2meter/70cm dual-band radio - that unit is good for 24 hours of average operation on FM.

Backing that up if I need more is a 34 amp/hour gel-cell that I can also use with my portable HF station when needed.

Plus I have a few other smaller batteries hanging around for various applications.

Unless you have a pretty substantial [read HEAVY] battery in your UPS, they are typically designed to allow you to shut the equipment down or keep 'em up when the lights flicker - lot's of guys rig a spare 12 volt power line to allow them to connect to station batteries of much greater capacity - I'm told Anderson Power Pole connectors are useful for such applications.  Some of the larger UPS do use a 24 volt input however.

A lead-acid battery yields about 1.35 amp/hours per pound so that can help you judge an unknown battery.


Posts: 146

« Reply #7 on: April 02, 2008, 09:37:48 AM »


You've gotten a lot of good advice here. In an emergency solar panels won't do you much good unless it is prolonged (and unless you've spent a LOT of money on the panels), and then a generator will be better.

The choice of a generator is important, as they don't all have a nice sine-wave output. The Honda EU1000i (or the EU2000i) recommended by KF6IIU has had some excellent reviews in terms of simplicity of use, low noise levels, reliability, and appropriate (for finicky devices like transceivers and computers) AC output.

If you use battery back-up for the initial phase of an emergency (a good idea, as the majority of emergencies tend to be short-lived) you might also consider an MFJ Battery Booster, which will up the output of your battery to 13.8 volts (it can be set to less, like 12 volts) as the batteries wind down. It will also stop drawing at a certain battery voltage to avoid damaging the batteries themselves. During an earlier discussion on this subject someone was nice enough to send me a program that helped to calculate how large (in terms of amp-hrs) a battery was required for your needs (including expected load and durations in it's calculations). If I can find it I'll let you know.

You might also consider LEDs for a light source, as operating in the dark is a PITA. I purchased some 12-volt lights in a tube (they resemble fluorescent lights except the tube is made of plastic and is clear, not frosted)... they have about 200 LEDs, draw almost no power, and are really bright. I use these for my shack and thus will have them already available for a black-out emergency.

73 de Carl AJ4DW

Posts: 146

« Reply #8 on: April 02, 2008, 10:15:20 AM »

Oh yeah...another useful device is West Mountain Radio's "Super PWRgate"

This device will automatically switch from an AC-based power supply to battery supply and also keep your batteries charged while on AC-based power supply.

Neither the PWRgate nor the Battery Booster is mandatory of course, but they can make life easier. Concentrate on getting your batteries first (and an appropriate charger), then get the add-ons when you have the money, that's what I did.

Posts: 3189

« Reply #9 on: April 16, 2008, 09:36:56 PM »

You vehicle's car alternator will charge a battery faster and cheaper than a solar panel. Besides if you already own a vehicle, you already have all the necessary DC generator power you will ever need to operate your radio equipment.

Similarly, the on board charging system in a riding lawn tractor can be adapted for this purpose.

You could also make a portable version of this by attaching a car alternator to a lawn mower engine.

Gl 73


Posts: 5

« Reply #10 on: May 25, 2008, 08:01:16 PM »

I found an interesting article in QST 58 short takes that talks about using a battery charger with gel cell or lead acid batteries. In short, you run the charger to your battery and run your shack, then you are always in "emergency mode"

Here is the article:

The product can be seen here:

I am a new ham, and have been thinking about making my shack emergency ready from the start.

Posts: 4

« Reply #11 on: June 03, 2008, 04:08:04 AM »

This is how the telephone offices run.  We run a -48V DC system. The batteries are on a continuous charge and the equipment runs off the batteries.


Posts: 5

« Reply #12 on: June 03, 2008, 10:20:33 AM »

An update to my posting. I was reading the manual for the West Mountain Radio Super Power Gate (Allows batteries and DC power supplies to be connected to same devices). I thought these warnings were very interesting. It might be nice to recommend that for HAMs that they should use ONLY Gel Cells or AGM 12V batteries indoors in the HAM shack. Every other battery should be shielded in the outdoors in case of explosion.

I have a friend who carries around a 12V battery camping, and uses a rectifier to run a TV or whatever. Its scary to think what could happen to those happy campers if that car battery blew up.

Caution: Handle batteries with knowledge and appropriate care. Batteries can have dangerous
chemicals that can spill out. Batteries can emit extremely explosive hydrogen gas that is
extremely explosive. Batteries, especially automotive and marine flooded lead acid, must be used
in a strong, ventilated enclosure. Sealed lead acid batteries are much safer but must be handled
and cared for correctly.
NEVER make the “last” connection directly to a battery causing a spark that could cause the
battery to explode sending debris and acid in all directions. Batteries can get very hot when
improperly charged or if a cell gets shorted. Batteries will explode during charging or discharging
for a variety of reasons. Think of a battery as if it were a can of gasoline, both may be safe, but
only if handled properly.
Chose a 12 volt battery with an ampere-hour rating according to your power needs. If the batteries are
placed indoors they must be sealed for safety reasons. Again, it is very important to place a fuse at the
positive battery terminal.
We cannot cover all the types of batteries here. But for use in the ham shack we recommend lead-acid
types because they offer the best price to power ratio. Gelled cells and absorbed glass mat (AGM)
batteries are sealed and are very safe. Some of these have a tiny positive pressure vent. We recommend
Gelled cells for use with the Super PWRgate because the battery charging circuit comes configured
properly and matches a 13.8 volt power supply. However, AGM batteries may be used, but we suggest a
slightly elevated voltage for the power supply, and a jumper change inside the Super PWRgate. We do
not recommend other types of batteries, such as “starting”, “deep cycle” and “marine” batteries, or
automobile batteries.

Posts: 6252

« Reply #13 on: June 15, 2008, 06:46:18 AM »

"Similarly, the on board charging system in a riding lawn tractor can be adapted for this purpose."

I'd watch it on that one--quite a lot of the 'generators' on those riding lawn tractors are simply a magnet on the flywheel/blower that goes by a coil 'pickup' mounted near the flywheel.  Those arrangements are not at all filtered, because they're designed just to put a charge on a battery.  They generate a pulsed power--something not too desirable when using radio equipment.  

Posts: 6252

« Reply #14 on: June 15, 2008, 06:52:52 AM »

I should have specified that those lawn tractor charging systems are OK to charge batteries, but if you intend to power equipment off of them you may damage that equipment because of the instability of those charging systems.
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