Newbie needs help

[TraderB]

I have some questions regarding solar setup and I hope you could help me a bit.

I have a solar charger with the following info:

Rated Voltage: 12V / 24V ( Auto Switch )
Rated Current : 30A
Max Input Solar Panel Power: 720W , Connect 24V Battery ( Connect 12V Battery, Max solar Panel Power: 360W )

I have 100 watt 6 amp panels, and a 12 volt battery bank.

Am I only able to put 3 of these panels on that charge controller? That means I need a controller for every 3 panels? Can they all feed into the same battery bank?

I've also received conflicting info on the size of wire to run from the panels to the charge controller...the panels are 65-75 feet away from the charge controller....and from the charge controller to the batteries, a distance of 3 or 4 feet.

One final question, I've been told to hook the controller up both of the following ways to the batteries...positive to the first battery, negative to the last battery in the bank...and then another source says both to the first battery.

As you can see, I am a novice at this, and although I am going offgrid, it wasn't by design, it's because of necessity, I was supposed to be able to get power there.

Right now I am powering my lights (12 volt mushrooms) with the batteries, and recharging with the generator until I have everything sorted.

Thanks for any help you can give.

[ButchDeal]

A few very important things to keep in mind:
you do not want to parallel batteries.
You do NOT want a 12V battery bank
you do not want a cheap charge controller
you do not want 100W pv modules

What you do want:
48V battery bank
250w + modules
MPPT charge controller

If you think about this, this voids most of your questions about battery connections, charge controllers, etc.

so you are going to want 8 6V batteries or 4 12V batteries in series for the 48V system
An 80a or higher Charge controller capable of handling ~4kw of PV at 48V
an inverter/charger to help maintain the battery bank with your generator.

[SunEagle]

Hello TraderB and welcome to Solar Panel Talk

You never mentioned the type or size of your batteries so it would be hard to say how you would wire them.

I will say that with a 75 foot distance between the panels and charge controller you want your DC voltage to be as high as possible so you do not have to run big wire to reduce the voltage drop.

[TraderB]

Thanks ButchDeal, but I have what I have. I understand what SHOULD be, but that isn't what is...this is why I asked what I asked. In the future that will be an option. It isn't right now.

Hello SunEagle, they are 12volt 100ah gel batteries. I am thinking I will need 2 or 1 gauge wire for the run to the charge controller most likely, at this distance. I am going to see if I can relocated the panels closer, can probably get them within 40 feet.

[ButchDeal]

Thanks ButchDeal, but I have what I have. I understand what SHOULD be, but that isn't what is...this is why I asked what I asked. In the future that will be an option. It isn't right now.

You haven't listed what you actually have.
Charge controller model?
battery models?
inverter model?
how many 100W modules?

it seems that if you already have a CC it is not the best one to have and not enough of them. You would be better off with an MPPT. you can use your 100W modules with a higher amp MPPT CC, at higher voltage. This would be more efficient and allow smaller wire between modules and CC.
If you don't already have an inverter then a 24V or 48V inverter would make everything much safer and cheaper, just reconfigure the batteries to a higher voltage. This would also double or quadruple the ability of the CC.

Some times it is cheaper to change some parts than continuing down a (12V) road.

[TraderB]

You haven't listed what you actually have.
Charge controller model?
battery models?
inverter model?
how many 100W modules?

it seems that if you already have a CC it is not the best one to have and not enough of them. You would be better off with an MPPT. you can use your 100W modules with a higher amp MPPT CC, at higher voltage. This would be more efficient and allow smaller wire between modules and CC.
If you don't already have an inverter then a 24V or 48V inverter would make everything much safer and cheaper, just reconfigure the batteries to a higher voltage. This would also double or quadruple the ability of the CC.
Some times it is cheaper to change some parts than continuing down a (12V) road.

Thank you,

I do not have any inverters yet.

I have a Sun YOBA Solar30 charge controller

The batteries are automotive blems, no label, but bought as 12 volt 100AH gel..yes, I know they aren't normally rated in ah, but cca, but they assured me they were....whether they are or not, i don't know. I have 3. They currently run my lights when I am there, and I charge them when they get down to 12.3 or so, which is about once a week. I am purchasing 6volt GC batts soon...soon being a relative term, probably 2 at a time starting next month.

I have 4 100 watt Eco-solar poly panels..I got them because they were cheap, with the intention of using them while I am building, then moving them to the pump house for the well. Things change though, and the loss of 1 income has put a huge damper on everything, so I have to make do for now.

I agree it can be cheaper, and I will try to take the correct path, but I have to use what I have now, but purchase anything else I need thinking ahead, like the inverters.

Edit: my boss is going to pick up an Outback FLEXMax 80 MPPT charge controller for me. So that is a start.

[Mike90250]

Batteries
You state they are GEL. Are they really gel or could they be AGM ? Gel batteries can only be trickle charged, like for a emergency EXIT light.
You say you plan to get Golf cart batteries. Better.

Pump House
What is the pump? It's very likely a 12V system will not be able to run the pump, if it's any larger than 1/4hp

[TraderB]

Batteries
You state they are GEL. Are they really gel or could they be AGM ? Gel batteries can only be trickle charged, like for a emergency EXIT light.
You say you plan to get Golf cart batteries. Better.

Pump House
What is the pump? It's very likely a 12V system will not be able to run the pump, if it's any larger than 1/4hp

Yes, I was mistaken Absorbed Glass Mat batteries, I called them to verify.

The pump is a SunRotor SR-12 pump, 4 gallons per minute from 350 ft in full sun, using 200 watts of panels. It was recommended by Backwoods Solar for my application.

[ButchDeal]

pump info https://www.sunrotor.com/systems/sr-12-pump-controller

depending on the controller you have it could work with 24V or 48V battery

[TraderB]

Ok, so...since I will be doing a 48volt system, I happened across some 400 watt 49.44 volt panels. It seems these would be an excellent matchup, correct? Under $300 each.


STC Maximum Power 400W
Voltage (voltage) Operation Optimo 49.44V
Optimum operating current 8.09A
Open-Circuit Voltage to 60.4V
Short-Circuit Current 8.59A
Efficiency Solar Cell 17.80%
Efficiency Solar Module 15.60%
Operating Temperature -40to85 ℃
Voltage (Tension) Maxima System 1000VDC
Maxima Series Fuses 15 TO
Power Tolerance 0- + 5W
STC: Irradiance 1000W / ㎡, 25 ℃ Temperature Modules, AM = 1.5