Simple Solar Panel question regarding charge controller and panels

[teampow]

Just to be let it be known, they'll provide no warranty if I end up running it nor can I return the set up anymore.

So I am running a SRNE 100/40A Charge Controller on a 24v battery bank. A shop recommended me two trina solar 500 watt vertex panels with these specs:

500 Watt Panel
Open Circuit Voltage (V) 51.70
Maximum Power Voltage (V) 42.80
Maximum Power Current (A) 11.69
Short Circuit Current (A) 12.28

They told me to wire in series but It looks like I'll over exceeed the VOC since it will be 103+. I am thinking of just wiring in parallel myself so the VOC will still be 51.70 way under the 100v limit. I know that these numbers vary with temperature right? Just trying to figure out what to do before I blow some stuff up lol. Simple question, let me know. I don't know who else to ask since this is the only solar shop really where I am physically located.

 

[teampow]

By the way I'm located in the Philippines! Shop seems uneducated lol

 

[teampow]

Not sure why the commented posted twice. sorry

 

[Rocketman]

That is a really bad combination of SCC and panels.

I see a few options…

1. All three in parallel - you will need fuses for each panel. Your cable after the parallel will be carrying over 33amps - so and 8awg or higher. (You probably should have a good solar combiner box and not just the three into one cables).

2. If you want serial - get a new SCC like a Victron mppt 250/60.

3. Can you use (and get) one more of that exact panel? If so wire 2s2p - you will need a new SCC - like a Victron mppt 150/70. This will keep the cable to 22amps so the standard 10awg will work - as long as not a long distance to the SCC).

4. Or get another SCC - hook 2p into your current SCC and 2p into a new SCC (if your new one is 150v you could then go 2s).

Good luck with your project

 

[teampow]

That is a really bad combination of SCC and panels.

I see a few options…

1. All three in parallel - you will need fuses for each panel. Your cable after the parallel will be carrying over 33amps - so and 8awg or higher. (You probably should have a good solar combiner box and not just the three into one cables).

2. If you want serial - get a new SCC like a Victron mppt 250/60.

3. Can you use (and get) one more of that exact panel? If so wire 2s2p - you will need a new SCC - like a Victron mppt 150/70. This will keep the cable to 22amps so the standard 10awg will work - as long as not a long distance to the SCC).

4. Or get another SCC - hook 2p into your current SCC and 2p into a new SCC (if your new one is 150v you could then go 2s).

Good luck with your project

Hey thanks for the reply, just to be sure it's two panels not three. Still same recommendations? They gave me a Y for the two panels and 10 awg wiring.

 

[Rocketman]

D’oh. Somehow I read it as three panels…

So the Y is for a parallel setup. (Serial would not use a Y). The Y will be fine for two panels.

The 2p setup will work well (Which was part of #4). The 2p will have 22amps in the wire - so 10awg is just fine (as long as it is not a really long distance)

 

[teampow]

D’oh. Somehow I read it as three panels…

So the Y is for a parallel setup. (Serial would not use a Y). The Y will be fine for two panels.

The 2p setup will work well (Which was part of #4). The 2p will have 22amps in the wire - so 10awg is just fine (as long as it is not a really long distance)

I can't thank you enough for the reply and help, one last question. What's "too long" of a distance?

Any quick guide or video for me to learn about amperage and wiring? Thank you again in advance.

 

[Rocketman]

There are charts for that - how long of a distance do you have?

 

[MrM1]

 

[gelmjw]

With up to 100ft of 8Ga wire on the solar side of the controller, you can sustain a 10% drop from 42.8 to to 38.52V and still have all the Volts needed to charge a 24V battery.

On the battery of the controller, you want to keep the loss lower than 3%. Keep that length as short as practical. Up to 10ft of 8Ga would be fine for 40A.

That's nice, all 8Ga!

 

[teampow]

Thank you everyone for the helpful replies! I bought a small solar set up for my 1 year old daughters ventilator. Here where I currently live in the Philippines they have power outages that last more than 12 hours. I'm currently using an Ecoflow River Pro but we all know that's just not enough :D