12v MPPT and 24v MPPT vs 24v PWM Test
Got a chance to try out comparing amps to the battery using MPPT vs PWM on a 24v battery bank and comparing those with the usual MPPT on 12v with my 230w panel. The bank is four 6s, so it was easy ...
Forum Discussion
The typical 230-250W panel is 6x10 or 60 cells or 30V which is very common for these sized panels. Using a panel like this doesn’t give a MPPT controller much room on 24V batteries especially with bulk charge at 28.8V+. BFL posted the input controller voltage was 29V with his 230V panel and battery at 25.5V . I’m wondering if the MPPT controller was very likely in PWM mode or limited MPPT which could account for the output being the same as the PWM controller.
MPPT works best by having higher input voltages and then using the excess watts to raise the output amps above Isc, otherwise it defaults to PWM mode.
A different PWM vs MPPT test would be with a 72 cell panel which would be 36V. That then would be relatively equivalent to a typical 36 cell 18V 12V panel comparison on PWM and MPPT controllers. I’d also prefer a 24V load during the test to keep the battery voltage in check with the focus on controller output vs battery charging. But I also appreciate the challenge for the rest of us to do our own testing!
MPPT works best by having higher input voltages and then using the excess watts to raise the output amps above Isc, otherwise it defaults to PWM mode.
A different PWM vs MPPT test would be with a 72 cell panel which would be 36V. That then would be relatively equivalent to a typical 36 cell 18V 12V panel comparison on PWM and MPPT controllers. I’d also prefer a 24V load during the test to keep the battery voltage in check with the focus on controller output vs battery charging. But I also appreciate the challenge for the rest of us to do our own testing!
