Solar panels, controllers, batteries...

[truckirwin]

Total re-do of my '74, 31ft Excella - building it out for boondocking and far away adventures...

I am redoing the electrical systems and planning to power entirely on solar with a small back up generator (honda 1000 LP). And will have one circuit of plugs for shore power, but not intending to rely on it.

Questions:
I am looking at a set of flexible panels to mount directly to the roof and am wondering how much is just right... electrical will be minimal, switching to LP heat, hot water etc. No AC. No fridge (Super duty ice chest). All lights will be LED etc. I will need to be able to power electronics - mostly iPad/phone, small laptop etc.

What about batteries? Thinking of a bank of 4 - 6 deep cycle marine batteries... but I simply just have no idea yet of system requirements.

Any suggestions more than welcome.

-Truck

[Jammer]

Rule of thumb is 300 watts of panels for most uses. Not many success stories out there with flexible panels. Lots of good reports from people who installed panels from amsolar.

What size batteries... Group 27 deep cycle batteries are readily available. 4 of those would be typical for an Airstream with solar where there is the possibility of running the generator if necessary.

At higher latitudes and in cloudy climates solar is less effective so in WA you would want to err on the side of more panels.

[drboyd]

Others with more diverse experience may jump in here; this topics might also be moved to the "solar" section of the board.

Your situation sounds much like mine - no A/C, no microwave. All I'm trying to do is to run a couple of CPAP machines and the furnace blower overnight.

I have run the furnace overnight on a single deep cycle battery; the CPAP machines may take that much as well. I went with (2) 100 watt panels and a MPPT controller, feeding into (2) Costco deep cycle marine batteries. I have about 90% confidence that this system will do what we want.

Taking weight into consideration, you might be better off with (2) AGM batteries as compared to the (4) marine batteries; the usable storage should be similar. I went wtih the marine batteries for cost. You can see the trials and tribulations of my solar install here.

[truckirwin]

Thanks all, checking out AM Solar - any others? Looking at just getting the 'all in one kits'... keeping it simple.

[DKB_SATX]

I've moved this to the "Generators, Batteries & Solar" subforum.

drboyd: When boondocking I run my CPAP off a pure-sine inverter with a single 100AH AGM battery. I made the mistake of believing the specs from the CPAP manufacturer. I find that the battery will run my CPAP for 3 nights (6.5-7 hours/night) before the inverter complains about the input voltage! I'd have bought a smaller/lighter battery if I'd realized. I'd also have bought a CPAP that runs on DC if I'd had the Airstream before the CPAP, but the inverter has other uses so I'll get over it.

[Jim Flower]

Truckirwin ,
You can't go wrong with a complete system from AM Solar. Bigger is better. I have a system (not AM Solar) that requires little thinking on my part. 4 group 24 AGM batteries, 2000 watt pure sign wave inverter, Go Power controller, about 300watts of panels. All outlets are powered by the inverter. I run the fridge and water heater on propane. I use what ever I want without concern. TVs, microwave, electric coffee maker, hair dryer, fantastic fans, and run the furnace at what ever it takes to keep the place comfortable when travelling or camping. My son gets by with a 100watt system from AM Solar. He is way more frugal than me but does run an Amp for his guitars. Go with the best and do it in stages if you have to. Do not skimp on equipment quality or wire size. I never need shore power unless I need air. Jim

[BigAl]

For what it is worth I installed 4 68 watt flexible solar panels on my 31 foot trailer.
They are large for their output. 15.5 inches by 9 feet long. They are amorphous panels which means that they have less output per square foot than the other types out there but they are pretty good when partly shaded. I am very happy with the results I have gotten. Also since the company went bankrupt the panels were very cheap on Ebay.
About $120.00 each when I got mine.
Al

[drboyd]

If building up the solar system as needed is under consideration, think about the things that will be difficult or expensive to change.

Example: Wiring from the combiner box down to the charge controller. Go with at least 4 AWG here.

The charge controller, also, won't be that much more for more amperage rating. You definitely want to go big on the charge controller right from the start.

I'm sure that AM Solar will sell you an easy-to-install quality system, if you decide to go that way.