What gauge wire between the PV & the controller?

[KA1J]

I have four 400 watt Q cell panels, the information on these is here:
https://cdn.myced.com/images/Products/ZZ0000/ZZ3048/00000/ZZ304800120_DS.pdf

Voc - 45.30

Isc - 11.14

Vmpp - 37.13

Impp - 10.77

I am planning on running these in series and there will be a roughly 50' run of wires from the Panels to the controller.

Looking at the voltage drop calculator I came up with the info in the following link.

https://www.calculator.net/voltage-...ceunit=feet&amperes=10.77&x=29&y=11&ctype=nec

I'm thinking of using a pair of 10 gauge wires running 50' to the controller. The calculator says there would be a .71% voltage drop, not that much but I had to guess at the Power Factor (PF), I don't know where to generate that data.

Then I thought about paralleling two and running those pairs in series which made a voltage drop of 2.83% as seen below. It looks like all things equal I should just stick with running all 4 PV in series.

https://www.calculator.net/voltage-...ceunit=feet&amperes=21.54&x=80&y=25&ctype=nec

My main question is with these 4 panels in series, will 10 gauge should be to the controller?

My other question is if I were to series parallel the PV, it would help mitigate shading on one pair of panels, but would 10 gauge still be OK for a 50' run given the four panels I have?

Thanks.

 

[Supervstech]

10 should be fine either way, I’d run 8 in case I decide more solar is needed. If shading could hit one or more panels, 2S2P would be better, if the voltage gets hit enough to charge reliably.

 

[KA1J]

Thank you for the reply. I can't get more panels at this location, no more room unless I put it on the house & I'm selling soon and I'll have a more robust setup at that time. For now these 4 panels will have to do & they do get shade. I can do 2S2P and that might be better because of that shade, it's just the amps will be a bigger factor so I've been paying more attention to going for volts & trying for lighter wire.

Good to know the 10 will be OK either way.

Tnx.

 

[HRTKD]

Don't forget that your solar charge controller will need to be capable of handling up to 200 volts on the input side. If you're located in a cold climate area, those panels could produce close to 200 volts.

10 gauge wire should work. Make sure you're using actual PV wire that is UL 4703 rated.

 

[KA1J]

Thanks for the reply. Yes, I chose the Victron 250/100 which is overkill but will allow any reasonable flexibility I will likely encounter.

The wire I have has silicone insulation, 10Ga 1050 strand, tinned copper wire, 600V rated, 200C to -60C .

 

[HRTKD]

The wire I have has silicone insulation, 10Ga 1050 strand, tinned copper wire, 600V rated, 200C to -60C .

Yes, but is it UL 4703 rated? I can't find much information out there that says that silicone insulated wire is acceptable for rooftop/PV implementation.

 

[KA1J]

I'd like to have the panels on the roof but these are being mounted on a rack at the far side of the garden on a wood frame. I'll be running these buried to the house in PVC. I'm not hooking into the grid, I'll be running my Ham Radio equipment & maybe a refrigerator from solar. I'll plug all of it into the inverter. It's mostly an emergency power source like a generator, so according to the town hall, there's no permit needed.

 

[PVorBust]

I had to guess at the Power Factor (PF), I don't know where to generate that data.

Unless I'm missing something, Power Factor (PF) is only relevant to AC circuits and can be ignored.

As for the cable, for a given current, the voltage drop is a constant regardless of system voltage.
Compare 10V @10A vs 100V @10A on the same cable with 1V drop.

the 10V system will give you 9V - 10% loss
the 100V system will give you 99V - 1% loss

 

[Quattrohead]

This sounds like a temporary setup so regular 14AWG is perfectly fine.
It is such an American thing to oversize stuff. Who said 8AWG lol

Result​

Voltage drop: 3.35
Voltage drop percentage: 1.85%
Voltage at the end: 177.41
Remember this is max drop under perfect output conditions.

 

[sunsurfer]

10 gauge wire should work. Make sure you're using actual PV wire that is UL 4703 rated.

So you are saying the 24 gauge speaker wire is a no go? Not that I have ever done that in a pinch.

 

[Quattrohead]

So you are saying the 24 gauge speaker wire is a no go? Not that I have ever done that in a pinch.

Pure no oxygen copper you will be fine.
Strip the high grade silicon sheathing off to increase heat dissipation.

 

[sunsurfer]

Pure no oxygen copper you will be fine.
Strip the high grade silicon sheathing off to increase heat dissipation.

Some times the vinyl comes off on its own!