PV upgrade decision
Right to the point: should I upgrade to a bigger panel or to an mppt controller? More info for those that take the time to read: I have a 100 watt, 21 ish volt panel and a pwm controller right ...
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Thanks for the link. I hadn't seen they were up that high yet. Assuming that's the module the OP is talking about I will change my advice. There is almost no advantage what so ever to that module with a PWM controller vs. his 100 watt module.
The Imp of a 100 watt module is likely around 5.5 amps. The Imp of that module is around 6 amps. This means you would only gain .5 amps of charge thru a PWM controller.
You really need an MPPT controller to take advantage of that module. It's Voc is around 68 volts. In cold weather the Voc could go well over 80 volts. That probably rules out a lot of the inexpensive MPPT controllers.
Sunpower used to require their panels be positive grounded. If I'm reading the spec. sheet right this one does not require that. However, I'd verify for sure because it would probably be really hard to have a positive ground solar system in a negative ground RV.
The Imp of a 100 watt module is likely around 5.5 amps. The Imp of that module is around 6 amps. This means you would only gain .5 amps of charge thru a PWM controller.
You really need an MPPT controller to take advantage of that module. It's Voc is around 68 volts. In cold weather the Voc could go well over 80 volts. That probably rules out a lot of the inexpensive MPPT controllers.
Sunpower used to require their panels be positive grounded. If I'm reading the spec. sheet right this one does not require that. However, I'd verify for sure because it would probably be really hard to have a positive ground solar system in a negative ground RV.
