Solar Cynergy Panels

BFL13 wrote:

Shadow Catcher wrote:
I have a high voltage panel that required an MPPT controller, this works better for shaded camp sites as I am getting something from sun up to sun down and in shade. Typically I will see 36V with the panel shaded.
I would also not hesitate to buy these panels.

Please explain this claim. You see this claim being made at times, but no measurements to compare or how that can even be true. A panel is what gets the sunlight, not the controller, so what does it matter if the controller is MPPT or PWM? The panel starts to work when it gets light out and stops when it gets dark at the very same time regardless of what controller you have.

I have been using two set-ups with one PWM and the other MPPT and have not noticed anything that supports the claim that the MPPT would work better in shaded sites or in low light or that "solar wake-up" times are different.

There was a link to a MorningStar blurb that explained you could use extra wattage panels above the controller's rating for amps which would overheat a PWM but the MPPT clips the amps so the controller wouldn't overheat.

So they said with the extra wattage you would get more amps at lower insolation than you would get with less wattage at that same insolation. Well, of course you would! But the claim is made AFAIK that you would do better in low light with the same wattage if you had MPPT instead.

You do get a bit more in amps (at high, not worth it, cost if using 12v panels IMO) with MPPT than with PWM at all times so what is special about low light or shade times? If the claim is true, then there should be an explanation and some test figures for how much more you get.

If anybody has seen such an explanation, please link it. Thanks

BTW, my 230w/MPPT gets 15.5amps where PWM would get 14.5a. If 1 amp for say 7 hrs a day --7AH more on the daily haul-- is "worth it" to you where the MPPT controller costs $300 and the PWM costs $30, then go for it. If for some reason one 230w panel costs so much less than two 115w panels, or if you don't have room for two 115s but can fit a 230, then that's different.

Hi BFL, the high voltage panels typically produce 2 times the voltage per panel (twice as many cells).

This means if a shaded 36 cell panel might produce 10 Voc, while the same shaded 72 cell panel will produce 20 Voc.

The MPPT controller can load the array and send power the battery bank while the PWM controller will be in cut-off since the panel voltage is below the battery voltage.

Ken