Quick Test of Eco-Worthy MPPT Controller
Ordered it on 3 Oct arrived at the door 23 Oct free shipping. Controller rated to 42V so watch that. EG I have it on one 230w panel, Voc 37v at 25C, so would be more Voc at cold temps. Not ab...
Forum Discussion
BFL13 wrote:
I have hopes of getting 16.5amps or so when panel is getting full Isc and temp is not so high that it kills the voltage the MPPT needs to feed itself.
What makes you think the MPPT quits operating before PWM?
Lets do a quick analysis of panel voltages and temperature.
A BP 350 panel has a Voc = 21.8V and temperature coefficient of -80mv/degree Celsius.
If we assume it fits the form of y = mx +b, then the panel voltage is predicted by Voc = -.08V/Celsius * T + 23.8V when referenced to 25 degrees Celsius.
If we use Voc = 14V as the cut-off voltage for both the PWM and MPPT, then this panel would reach that voltage at 122.5 degrees Celsius.
A BP 175 panel has a Voc = 44.2V and temperature coefficient of -160mv/degree Celsius.
If we assume it fits the form of y = mx +b, then the panel voltage is predicted by Voc = -.16V/Celsius * T + 48.2V when referenced to 25 degrees Celsius.
If we use 14V as the cut-off voltage for both the PWM and MPPT, then this panel would reach that voltage at 213.8 degrees Celsius, a much higher temperature.
If comparing side-by-side, the MPPT would still have 28.6V available to operate when the lower voltage PWM panel hit its 14V wall.
The MPPT wins...
