Solar Panel Voc-MPPT?
Wondering if there is any relationship between measured Voc and MPPT performance with a 24v panel. My 12v panel has a Voc rating of 21.9 and Isc of 8.2, but I often see 8.2ish when Voc is only 20....
Forum Discussion
BFL13 wrote:
Thanks, I remain optimistic! :)
Getting an extra half an amp when batteries are below 80% SOC seems odd, but could be that MPPT watts thing again. It would not be from the battery acceptance rate tapering the amps at higher SOC.
10 amps on four batts is 2.5a per battery so that would be acceptance rate for about 97% SOC at mid 14s voltage. If 10a is the charger's max amps, it should keep doing 10a right up to the high 90s in SOC on that size of a battery bank.
But with solar charging you get that IV curve tapering in the 14s with 12v PWM so your 10a will be a bit lower from that. With 24v panel MPPT, that IV curve thing at 12v battery voltages is replaced by the all that MPPT mishmash for what happens, but you would still be in the high 90s ( I think)
It's really 10A into two batteries in my case(Four 6V GC), or 5A per bank. When the batteries are down in the 50%SOC, the battery voltage drops just enough from 80%SOC voltage so with MPPT power stays the same, amps rise slightly. And again it's two 12V battery banks at 50%SOC not one, I suspect the effect might be less with one 12V battery bank.
