60 Cell Panel vs 24v Bank MPPT and PWM UPDATE
UPDATE--results with MPPT posted 1 June. Got a chance to run this test today with no clouds but a slight haze up high so not quite 1000 insolation, showed as 8.93Isc vs rated 9.0, however that did ...
Forum Discussion
Take a look at the panel spec.
The maximum power point is defined at a cell temperature of 25C:
Vmp = 30.2V
Imp = 8.43A
You measured cell temperature of 46C.
The panel has a voltage temperature coefficient of -0.34%/C.
That means your maximum power point is at:
Vmp = 30.2V * (1 - .0034 * (46-25C)
Vmp = 28.0V
Your maximum power point is at 28.0V, yet panel voltage is at 30V. That means the controller is not operating at maximum power.
BTW, no one says it's impossible to get some current of of this panel when connected to a 24V battery. It is impossible to get to the maximum power point when battery voltage is greater than Vmp. In this scenario, the best you can do is get Isc out of the panel.
The maximum power point is defined at a cell temperature of 25C:
Vmp = 30.2V
Imp = 8.43A
You measured cell temperature of 46C.
The panel has a voltage temperature coefficient of -0.34%/C.
That means your maximum power point is at:
Vmp = 30.2V * (1 - .0034 * (46-25C)
Vmp = 28.0V
Your maximum power point is at 28.0V, yet panel voltage is at 30V. That means the controller is not operating at maximum power.
BTW, no one says it's impossible to get some current of of this panel when connected to a 24V battery. It is impossible to get to the maximum power point when battery voltage is greater than Vmp. In this scenario, the best you can do is get Isc out of the panel.
BFL13 wrote:
The real point is that it got the batteries to 30 plus volts no sweat in horrible insolation conditions. Yet another case of doing the "impossible"
