diy solar

diy solar

Open Circuit Voltage

I'm seeing some panels are temp coefficient of Voc rated in mV/C instead of %/C. so, I would presume I take the lower limit in mV, convert it to volts, then divide that by the Voc to get the %/C.... am I on the right track?
 
%/ºC = V/ºC / Voc x 100

So yes, you are on the right track.
 
fantastic, thank you! I'm finding the 1.25 temp correction is definitely a good and safe rule to follow, even if a bit overkill.
 
just remember that to get a same wattage rating at lower voltage the panels have to be at higher amperage. then you have all kinds of fun with larger wires/combiner boxes/etc as mentioned previously. two series-parallel strings temperature corrected can bump you over 30amps! i just disqualified one of my panel option because of this, even though the voc was under my max limit
 
PSA! i'm bumping this topic back to the top as it's CRITICAL you account for temperature correction in your system plans.

I just hit 108% efficiency for the first time on my 2kw array this morning as it's 39degF outside! If you aren't temp correcting and accounting for it both with VoC for your SCC input as well as for wiring, you're potentially going to blow your SCC if you're in a colder climate.
 
Last edited:
Back
Top