What voltage/amp should I use on these panels

[NwCali]

I can either do 4 panels at 100 Volts / 20 Amps with a expected 87 volts, or I can do 3 panels at 150 Volts/10 amps with 143 volts coming out the end... Also this is "open circuit" voltage. Should I be basing this off VMP instead? If so then the voltage drop might be more with the lower VDC that would be coming thru.

My original plan was to hook it up and measure it in real time... But I'd rather have a clue which will work better up front.

My charge controller says its good up to 170 volts, so I don't see why either would not work.

But which will give me more real world watts?

I ended up with this charge controller https://www.amazon.com/dp/B0827DWCL6?psc=1&ref=ppx_yo2_dt_b_product_details

I hope one day to "upgrade" it but given its price point/availability/specs this is what I have for now. But I've yet to find its mppt voltage range.

Thanks for any input/help!

 

[Bud Martin]

The total Voc should not exceed the PV input rating of the SCC, you may have to also factor in about 15% higher if you are in cold climate.
What is the spec of the panels?

 

[NwCali]

The total Voc should not exceed the PV input rating of the SCC, you may have to also factor in about 15% higher if you are in cold climate.
What is the spec of the panels?

143vdc voc, 170 vdc charge controller, its covered on that end. Thanks...

 

[Bud Martin]

Panel has 143Voc, or you are talking about Voc of 3 panels in series?
What is the printed Voc of the panel?
50Voc for each panel based on " I can do 3 panels at 150 Volts/10 amps with 143 volts coming out the end.."?
If you are under 170V (factor 15% increase in cold temperature, so factor in 15%, the Voc can be as high as 164V) then you will be fine.

 

[NwCali]

Bud, I am not concerned with what your covering...

Wanting to know if the three panels at said voltage/amperage will put out more/less than 4 panels at said voltage/amperage given the higher line loss.

I'll just hook it up and measure everything and go from there, I'm 99% confident 4 will work better.... But you also have other variables with more panels (shading being one).

Longer runs have obvious benefits from higher voltage, which is what I'm dealing with here.

 

[Bud Martin]

OK, may be I do not understand what panels you have as stated in post #1.
Vmp x Imp = panel Wattage.
Higher Voltage and lower current will have less Voltage loss on the wires feeding the SCC, and you can use smaller gauge wire compared to lower Voltage and higher current.