600W Solar - Getting 420W Max
I have 5 120W Solar panels flat mounted. I am in Mission TX at a FHU park for the winter. It is giving me a good place to test my system out. Back in the NE there are to many trees. I have seen a max ...
Forum Discussion
Panel heat loss means you don't see rated wattage even when it is aimed at the sun. Typical loss of 0.43% per degree above 25C means 0.43 x 20 = 8.6% at 45C (often quoted as "normal" operating temp)
250w panel at 25C is now 21.5w less at 45C = 228.5w
(that's with ambient 25C and panel now at 45C (heats up within three minutes of being placed in the sun)
Now you have say 2% wiring loss from panel to controller, lose another 4.5w = 224w. Controller loss 5% = 11w means output is now 213w. This is in perfect conditions with panel aimed.
So now you divide that 213 by battery voltage to get your charging amps. 13v - 16.4 amps and 14v - 15.2 amps.
BTW this makes it so bogus when people say you "waste" a bunch of watts when using PWM and you don't waste them using MPPT. The watts with MPPT are less too.
250w panel at 25C is now 21.5w less at 45C = 228.5w
(that's with ambient 25C and panel now at 45C (heats up within three minutes of being placed in the sun)
Now you have say 2% wiring loss from panel to controller, lose another 4.5w = 224w. Controller loss 5% = 11w means output is now 213w. This is in perfect conditions with panel aimed.
So now you divide that 213 by battery voltage to get your charging amps. 13v - 16.4 amps and 14v - 15.2 amps.
BTW this makes it so bogus when people say you "waste" a bunch of watts when using PWM and you don't waste them using MPPT. The watts with MPPT are less too.
