mom wants solar on her class C.... i need to do this cheap.

Unisolar, I believe, is out of business; which would mean that those are 'new, old-stock' panels. They are 18' long... is there room on the RV for 2 of them to be mounted without having vents or A/C or antennas cast shadows on them?

Hi,

Yes, if price is the question it is cheaper to go PWM than MPPT. I do recommend trying to find a controller that has a temperature sensor probe for the battery bank.

The panels Salvo recommended are good.

I'd spend a bit more on a controller that allows for expansion such as this one: Tristar 45 amp PWM

I would avoid mppt if you want to do it cheap.

Get two 12V, 140W panels for $160. The pwm controller costs about $30.

https://www.solarblvd.com/product_info.php?cPath=1_269&products_id=2668

let mom read all these post there,s more to this and maintence than she thinks.

Do some "serious" research on those flex panels and you will go with something else. I was all gung ho for them, until I did my homework and there is NO way they would end up on my roof.

I like that idea for ease of installation, but they have a minimum slope of 1:12 listed, and minimum temp for sticking it on of 50 degrees. For a winter install, you put just one 200w rectangular panel made for grid tie (approx. 30 something volts) and get a similar result with less wires and way less real estate gone from the roof.

I was advised that the rubber or tpm roof might pull upwards, so I put my panels in with big plastic mounts that hold it off the roof slightly, and allow removal without unscrewing the mount side that touches the roof. But, did have to put the RV sealant in each and every screw hole, of course. I agree with the poster above to get an MPPT controller with a remote. It may not take the place of a shunt type of ammeter/wattmeter, but will give a good idea of what's happening with the batteries. One big panel, or 2 small ones, some cables to cut up, some inline fuses and a switchable circuit breaker might put you a little over $700 in parts, but you will like having the solar always topping up the batteries to the right level.

Oh yeah, the stick on panels get very hot, since there's no airspace beneath them. Not sure what that does to the rv roof covering, either, and taking them off to check underneath would likely be difficult.

You can't use the $102 Eco-Worthy MPPT controller because it can't accept that 46Voc voltage input. Is more like 42v limit.

Next up in price would be a Tracer MPPT at around $140 that does have the voltage (100v) but IMO you should keep the voltage well below that to be sure. Which means put the 46v Voc panels in parallel not series. Others might say go two in series at 92Voc but pushing your luck IMO. Same with any other controller with 100Voc limit.

Next up in price is probably to near $300 but might have a few extra features. But would your mum ever use those extra features?

i saw that one... is it too much trouble to deal with the 24v to 12v?

If those panels work out I recommend the 20 amp Rogue controller $250 to get the power to the batteries.