Eco-Worthy 12v solar panels, Now drifting to... mono vs poly

greenrvgreen wrote:
jr, for maximum value start with a cheap PWM controller and nominal 12V (~18V) panels. Make them somehow portable, even if only to lean against your RV. Run these for a year and then figure out what the ideal system would be, and spend your big money and drill holes for that.

I wish I'd done this, I'd be $1500 richer right now. My Kyocera 315 panels and my FlexMax 80 are nothing but museum pieces, while my Renogy portables and cheap PWM actually get the job done. If I buy enough Renogy panels to bump the voltage, maybe I can get some use out of the Flexmax. But until then I've basically pineconed myself.

Consider:

--"Cost per amp" of panel at 12v PWM. Now SUBTRACT the cost savings of PWM vs MPPT.

--"Amps per square foot" of panel at 12v PWM. These are "actual amps" vs "potential amp gains" of MPPT, subject to heat loss, light clouds, etc etc etc.

Dont spend $500 additional on an MPPT (it really IS MPPT) controller than cannot possibly harvest an extra $500 worth of power over its service life.

I'm happy I started with a 100w portable setup. People say there are too many compromises with portables. So yes, they require handling, and maybe a locking cable depending on where you are. But on the plus side, you can often park in the shade while putting the panel in the sun, harvest a lot of watts, with minimal installation hassles, and cheaply. All of those good features are compromised on roof mount panels. :) :) :)

Someone who travels around a lot should have roof panels, no doubt. But the typical person who camps someplace for a week or so, with two batteries, LED lights, and commonsense use of energy, can get a lot or maybe all of his needs from 100 to 200 watts on the ground.

Now I'm going to add roof panels as the next step. But since I like shade, I expect to have to supplement with the portables when we camp in the summer.