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

JiminDenver wrote:
Interesting idea. You wouldn't have to heat the water tank, you could heat tile or brick.

Yup, you could heat just about anything. Your post in the other thread about 12V water heater elements got me thinking.

Snowman9000 wrote:

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.

As easy or as hard as you want to make it.



Knowing where you are at, for amps replaced, with this $16 device, in line.

Interesting idea. You wouldn't have to heat the water tank, you could heat tile or brick.

I was thinking of using the diversion power feature to heat the water in my steel water tank when camping in cold weather. The steel tank is under s dinette seat/convertible bed and could supply some heat exchange in that area. Really, it is all about using excess harvest and being able to store it, either as electrical energy as we do with batteries or as heat through an element. I've forgotten what the diversion circuit of the little Morningstar 15 will handle but I'm pretty sure it is not 15 amps. I'll check on that.

nice ride, snowman.

Just think, five to ten years from now, you'll be able to buy very efficient solar for about 50 cents a watt, even with inflation, and an adjustable power supply for about $150, that puts out 100 amps of clean power but only draws 12 amps.

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.

I keep saying the trailer IS my diversified load.

PT keeps on about diversion. He likes to heat water all afternoon just because he can, but then what do you do with it that evening before it gets cold overnight?

I shave in the morning and we like a shower and we are not about to change our habits. Since the water is hot from propane for that and there is 10( US) gallons of it, we can shower and wash 24hrs worth of dishes too after breakfast each day. No need for hot water till next morning. turn on the propane heater at wake-up, turn it off once the water is hot and that's it till the next time.

If no showers that day, just heat a pot full to shave with.

But you can still run extra loads "for free" in the afternoon when solar can do more than the batteries want by then. Good time to recharge the laptop or whatever. In our case in the summer when it gets so hot we want to run the big 120v ceiling fan, we can do that off the inverter and it is all done by solar, no effect on battery charging. Nice!

Yes, I threw out diversion, but no one bit. :)

I gotta a neat idea from sabconsulting's install. He mounted two panels on the roof of his truck camper, and put hinges on one side, and barrel bolts on the other. But it occurred to me, one could install barrel bolts on both sides, and they would double as hinges, as well! This would allow for tiling either way. In fact, you could install 8 of them, and have a four way tilt, just no swivel, provided access was easy enough.