Using a residential PV panel on RV

joelmyer wrote:
Thanks for the feedback.

Yes, 106 ah daily. I've put in LEDs so should be a little less.

I've been accused of speaking encrypted. By less amps coming down I meant from the panels on the roof to the controller down in the storage compartment behind the batteries. 250 watts @ 12 volts is a lot more amps than 250 watts at 24 volts. And the IsquaredR power lost in heating up the wire will be 1/4 with 24 volt panels. Yes from the controller to the batteries would be the same.

Hmmm... free power. I was mostly thinking getting the batteries fully charged. I spend $3/day on gasoline, $3/day on propane. Getting that second 250 watts on the roof will be hard.

LEDs save a lot. 2 double domes run 4 hours from winter sunset to bedtime is 24 AH before, or 5 AH after replacement. 20 AH less.

Amps from panel... The beauty of 24V and MPPT is that you don't lose amps - you lose watt-hours (or amp-hours, same thing). And very little at that. Daily resistance loss with 400W *24V array is ~2 AH or less. This is almost nothing. From 250W*24V panel the loss is not even worth talking about. But I would go for 400-450W, if roof space allows. For somebody who boondocks a lot and doesn't have unlimited budget, having not to not run a genny on most days and getting batteries fully charged would be nice. Or you'll run it half an hour for Bulk, and then solar will do the rest.

My batteries are full before 11 am in Baja winter, without a generator, though I use less than 40AH a day. For curiosity tried running all the loads other than MW, to draw ~90 AH and see how much I could harvest from the sun. Next day was sun with clouds and harvested ~70 AH, with my "regular" consumption pattern, i.e. not running the loads that I don't need. Then 100% full by 10 AM next morning. 490W array, 300 AH bank.