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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That 135 panel has an Isc of 8.37a and that's what you will get at the batteries with PWM until the IV curve slows it down somewhere in the mid 13s battery voltage on up. Isc might be 7.9 at 14.4v eg
A 100w panel would typically have an Isc of 6.4 and that's what you would get too.
I never noticed a drop in amps from the panel on hot days, but did see a drop in Voc. Isc goes up with temp and Voc goes down.
You still get full amps at battery voltage in the 14s with PWM until acceptance rate slows the amps down. Another thing that can slow the amps down then at 14.4v is a timer on the Absorption stage.
Now with MPPT the big question is whether that drop in Voc would correspond to a drop in amps! (which was my OP question) It seems it could well do so, because Power moves most with the component (I and V) that moves the most (volts) but I will have to see for myself with my set-up how much that might be at our location, temps etc..
A 100w panel would typically have an Isc of 6.4 and that's what you would get too.
I never noticed a drop in amps from the panel on hot days, but did see a drop in Voc. Isc goes up with temp and Voc goes down.
You still get full amps at battery voltage in the 14s with PWM until acceptance rate slows the amps down. Another thing that can slow the amps down then at 14.4v is a timer on the Absorption stage.
Now with MPPT the big question is whether that drop in Voc would correspond to a drop in amps! (which was my OP question) It seems it could well do so, because Power moves most with the component (I and V) that moves the most (volts) but I will have to see for myself with my set-up how much that might be at our location, temps etc..
