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Author Topic: New solar panel system  (Read 1696 times)

KF7YED

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New solar panel system
« on: July 28, 2019, 06:59:42 PM »

I lucked into a deal on a set of three 100W Seimens SR100 solar panels and I'm wondering what charge controller I can use with them. Intended purposes are to run my Yeasu 857D and/or to power or charge my camper battery. I'm about to install a new camper battery 12V 100AH, due any day. The seller of the solar panels also has a new-in-box Midnight Solar model Midnight Brat controller available if that can work. He hasn't tried them all together so I thought I'd ask the experts on here first.

Panel data:  







Midnight Brat data:
https://www.midnitesolar.com/productPhoto.php?product_ID=615&productCatName=Charge%20Controllers%20-%20Brat&productCat_ID=49&sortOrder=1&act=p

Battery data:
https://images-na.ssl-images-amazon.com/images/I/61eWRS7yN9L._SL1000_.jpg


Thanks in advance.  73




« Last Edit: July 28, 2019, 07:14:43 PM by KF7YED »
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N8AUC

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RE: New solar panel system
« Reply #1 on: July 29, 2019, 04:45:56 AM »

What charge controller you use depends on your battery chemistry, and how much current will be flowing.
What type of battery do you have: lead-acid, or Lithium-ion, LiFePO4, or what?

Now you said you have 3 x 100w panels. From the label, you can get around 18 amps from 3 in parallel. This controller will handle a 20 amp charging current if you run the load through the charge controller, or a 30 amp charging current if you don't. This controller will handle the charging side of things.

Do you intend to connect your load through the charge controller, too?

From the link you provided, it looks like what you have will probably work.
But it will only handle a 10A load current if you connect the load through it.

If you intend to run your 857 at full power, you should not run the load through this charge controller.  
This controller will not supply enough current to run a 100w transmitter.
Run the load directly from the battery.

Bottom line, if you hook it up properly, and you are careful with it, this controller should work. I'd get a beefier charge controller if it was me though.
« Last Edit: July 29, 2019, 05:08:21 AM by N8AUC »
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N8AUC

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RE: New solar panel system
« Reply #2 on: July 29, 2019, 05:20:15 AM »

Ok. It's a lead acid battery.

Same conclusion though.

If you are careful, and you run the load directly from the battery, this controller should work.

But if it was me, I'd get a beefier controller to get a bigger safety margin.
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K0UA

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RE: New solar panel system
« Reply #3 on: July 29, 2019, 07:14:47 AM »

Don't forget that many charge controllers have so much RFI that your HF operation will be nearly impossible.  There are charge controllers out there that don't.  Just like switching powers supplies. Some are extremely noisy some have no noise.
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73  James K0UA

K0UA

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RE: New solar panel system
« Reply #4 on: July 29, 2019, 07:20:27 AM »

This company was started by a ham and he claims his controllers are quiet.

https://www.diysolarforu.com/our_story.html
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73  James K0UA

K7AAT

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RE: New solar panel system
« Reply #5 on: July 29, 2019, 07:42:59 AM »

This company was started by a ham and he claims his controllers are quiet.

https://www.diysolarforu.com/our_story.html

Several of us in our area can strongly attest to the very LOW RFI from this guy's controllers.  We had conducted several tests on them and they are highly recommended for ham use.
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K0UA

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RE: New solar panel system
« Reply #6 on: July 29, 2019, 08:32:17 AM »

This company was started by a ham and he claims his controllers are quiet.

https://www.diysolarforu.com/our_story.html

Several of us in our area can strongly attest to the very LOW RFI from this guy's controllers.  We had conducted several tests on them and they are highly recommended for ham use.


Good to know.  Of course a linear controller would be quiet, but to get the maximum out of the panel you need a MPPT controller and in the past that has always meant forgetting about radio. If his MPPT controller is truly quiet than that would seem to be some good news  for hams. Thanks for your input.

We used a campground for Field Day that was 100 percent solar but I don't know what kind of controllers they used, but they were pretty noisy, especially on 80 meters.  I could see all sorts of trash from either the controllers or inverters on 80 on the waterfall of my 7300.  Fortunately I only operated FT8 on 80 meters so it didn't bother me at all.
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73  James K0UA

KF7YED

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RE: New solar panel system
« Reply #7 on: July 29, 2019, 08:39:56 AM »

So it sounds like this controller would be fine for the camper but I should run the radio(s) off battery.

Beefier charge controller---  hard to make a decision since I'm picking them up tomorrow morning. I told him I'd research the controller and maybe buy that, too, but a bird in  the hand, as they say... The price is nearly what I could get it for on Amazon, so it wouldn't kill me to wait if I had an alternative in mind. What should I browse for in controllers? MPPT... and "beefier" is what specs?

Thanks for all the quick responses..

Rick
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K0UA

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RE: New solar panel system
« Reply #8 on: July 29, 2019, 09:26:08 AM »

So it sounds like this controller would be fine for the camper but I should run the radio(s) off battery.

Beefier charge controller---  hard to make a decision since I'm picking them up tomorrow morning. I told him I'd research the controller and maybe buy that, too, but a bird in  the hand, as they say... The price is nearly what I could get it for on Amazon, so it wouldn't kill me to wait if I had an alternative in mind. What should I browse for in controllers? MPPT... and "beefier" is what specs?

Thanks for all the quick responses..

Rick

What we are saying is that some charge controllers will have a lot of RF emissions.  We (I) don't know if this controller he wants to sell you will or not. You can always run the radio off of the battery, the controller doesn't have to have outputs for the load. The testimonial from K7AAT is that the DIYsolar MPPT controllers are very low RFI emissions.
Go to the web page and decide for yourself. But a product made by a ham with emissions in mind seems to me a step in the right direction.  It is the direction I would take a risk on.
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73  James K0UA

K0UA

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RE: New solar panel system
« Reply #9 on: July 29, 2019, 09:43:50 AM »

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73  James K0UA

N8AUC

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RE: New solar panel system
« Reply #10 on: July 29, 2019, 01:00:09 PM »

So it sounds like this controller would be fine for the camper but I should run the radio(s) off battery.

Beefier charge controller---  hard to make a decision since I'm picking them up tomorrow morning. I told him I'd research the controller and maybe buy that, too, but a bird in  the hand, as they say... The price is nearly what I could get it for on Amazon, so it wouldn't kill me to wait if I had an alternative in mind. What should I browse for in controllers? MPPT... and "beefier" is what specs?

Thanks for all the quick responses..

Rick

The controller you are looking at is a PWM controller. This is the least efficient form of charge controller.
Only about 70% of the energy you capture with your panels will be available to charge your battery
It only handles 30 amps of charge current if you run the load directly from the battery.
If you run the load through the charge controller, it will handle 20 amps of charge current and 10 amps of load current.

If you have a choice, you really want an RF quiet MPPT controller. This is far more efficient than a PWM controller.
MPPT controller are able to supply 95% to 99% of the energy captured by your panels to charge the battery.
You also want to be able to handle 30 amps of load current, because your FT-857 wants around 20 amps of current to transmit at 100 watts.

The reason you want to be able to run the load through the charge controller is that it will prevent you from over discharging your battery, which
will reduce the number of charge/discharge cycles available over the life of the battery.

That's what I mean by a "beefier" controller.

If you are willing to reduce your transmitter output power to around 40 watts, you can get by with what you have.
This reduces the current requirements of the radio to a value your charge controller can handle.
Regardless of battery size, you must never exceed the current capacity of your charge controller.




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N8AUC

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RE: New solar panel system
« Reply #11 on: July 29, 2019, 01:47:13 PM »

There are two ways to wire up your panels to run your radio.

If you go with the Midnight Solar PWM Controller you are considering, and you want to run your radio at 100 watts output,
you have to wire it like this.....


+------------+        +------------+
| solar        |   +    | charge     |
| panels     |-------| controller  |
|                 |         |                 |
|                 |-------|                 |
|                 |   -     |                 |
+------------+         +------------+          +------------+
                                  |     |        +        |                |
                               + |-------------------|   radio      |
                                  |   - |                  |                 |
                                  |     |--------------|                 |
                                  |     |             -    |                 |
                             +------------+           |                 |
                             |  battery     |           +------------+
                             |                 |
                             +------------+

The load is not being supplied through the charge controller in this instance,
so you run the risk of over discharging your battery. But since the Midnight
controller can not supply the current your radio needs, you're stuck doing it
this way.

If you buy a "beefier" charge controller that can supply the current your radio needs,
you can wire it like this...

+------------+        +------------+           +------------+
|    solar      |   +    | charge      |    +     |                 |
|   panels     |-------| controller  |---------|                 |
|                 |         |                 |            |  radio       |
|                 |-------|                 |---------|                 |
|                 |   -     |                |     -      |                 |
+------------+        +------------+           +------------+
                                  |     |
                               + |     | -
                                  |     |
                            +------------+
                            |    battery   |
                            |                 |
                            +------------+

This way, the load current is managed by the charge controller.
You can do this when your charge controller is capable of supplying the current needed by the radio.
The benefit here, is that the charge controller will prevent you from over discharging your battery.
Over discharging will significantly shorten the service life of your battery.

If you want to protect your battery, and you insist on using the Midnight Solar controller,
you will need to reduce your transmitter output to around 40 watts to reduce the current needed
by the radio to a value the charge controller is capable of supplying.

You have three choices here:
1) Buy a charge controller that can handle the current your radio needs and run the radio through the charge controller. (Best choice)
2) Use the Midnight Solar controller, and power the radio directly from the battery, which risks shortening the life of your battery. (Worst choice - but do able)
3) Use the Midnight Solar controller, reduce the transmitter output to 40 watts, and run the radio through the charge controller. (compromise)

Sorry for the crappy "graphics".
« Last Edit: July 29, 2019, 01:49:37 PM by N8AUC »
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KF7YED

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RE: New solar panel system
« Reply #12 on: July 29, 2019, 03:09:40 PM »

N8AUC--- Excellent! Exactly the info I was looking for. I'll take a pass on this Midnite Solar Brat controller. That takes the pressure off to decide right away, too.

K0UA--- Great link to more info. Thanks. I had looked into solar a few year ago and never got into this much. Then I had this opportunity come along. I'm cheating by asking these questions: normally I would do more research... :)

Hmm. It just hit me-- I have the Buddipole Power Mini charge controller..  I wonder if that would work.
http://www.buddipole.com/powermini.html

Max Load Current: 25 A continuous
Max Solar Charge: Current 10A.



Thanks, guys.

Rick
« Last Edit: July 29, 2019, 03:21:48 PM by KF7YED »
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N8AUC

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RE: New solar panel system
« Reply #13 on: July 29, 2019, 05:44:01 PM »

Rick,
If those specs are correct, then yes that controller should work.
The margin on load current is a little thin for my tastes, but it should work just fine, IF it is RF quiet.
Make sure to set the parameters on the controller to match your battery and its parameters.

Also, test before you go into the field with this setup to make sure that the
controller you use does not generate RFI for your rig.
You don't want your solar charge controller to generate QRM that will prevent you from hearing anyone.

73 de N8AUC
Eric
« Last Edit: July 29, 2019, 05:47:16 PM by N8AUC »
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KF7YED

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RE: New solar panel system
« Reply #14 on: July 29, 2019, 07:33:48 PM »

Got it. I think I used it for Field Day 2 yrs ago. Just forgot I had it until this discussion. I remember having some RFI but I was also running a little 2kw Champion genny and I thought that was the culprit. I'll test and see before I put money into a different controller.

Thanks!

Rick
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