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....
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BFL13 wrote:
To clarify, by four batts I really mean 440AH whether four 6s or four 12s. The acceptance rate is wrt AH capacity and batt voltage.
Not exact but a rule of thumb. 10a per batt is 86%, 5a per batt is 90%, and 3a per batt is 97% SOC at 14.5v
thanks for the rule of thumb. Back to the charge current. when my batteries are near 80%SOC per trimetric, and on my PD combo good for 100A, IIRC I'm still getting 60+A, into them.
But with the solar, I was seeing 10A and mid 13's for voltage, limited in this case by the panels.
Looking at your rule of thumb, I'd say it matches my bank pretty good from my recolection. by 90%, charge current is definitely on the way down, don't recall the exact current, but 20A is probably in the range.
I usually stay on solar until I'm in the 40-50%SOC then just hammer the batteries for a few hours at 100A with the generator, then let the solar top it off. Once it's down to 20-40A charging current, may as well let the solar finish it off rather than let the generator run for hours.
