So, a six weeks ago I installed:
- 3*315W Canadian Solar panels (they put out about 9A @ 35W on spec
- Solar Combiner box off Ebay, 3*15A breakers wired in parallel
- Integrated solar charger/inverter (24V, 3kw pure sine inverter, 90A charger, MPPT controller)
- Victron BMV-702 Battery Monitor (uses shunt)
- 4 GC2 6V batteries wires with 2/0 cable
I'm parked seasonally so I built a stand alone battery box outside the RV and put the inverter and wiring into a rear compartment in my Surveyor SP295. Panels are mounted on the roof. My site is partially shaded for most of the morning, gets strong sun for four hours (when it shines of course
), then there's a couple hour break and two good hours of evening sun. The site is neither what an average camper would call full sun nor shady...in the middle and probably a good estimate of the 'average' campsite.
My use was defined by two things, one, however, foolish is that I wanted to run my outdoor fridge in the outdoor kitchen and be able to leave beverages and such...cold for when you get here. And second, was to be able to work a bit at the lake when here, so basic stuff like charging phones and running laptops with clean power. The larger inverter helps by having a large charger (using 40-60A max rate) and that we can run the microwave for baby food and quick stuff for kids. It also has enough capacity that it's no overwhelmed or struggling with simultaneous load.
The results are...well, predictable. My gut was that solar yields would be smaller than the 3 hrs that solar vendors predict and that I'd need to top up with the generator when use was heavy or sun is weak.
What it does:
-keeps the batteries topped right up while away, runs fridges and parasitic stuff with ease
-nearly keeps up on sunny days with heavier use of ~60-80AH a day, keep in mind it's 24V so that's ~1,800W a day
-can keep up with use of 40-60W per day ~1,300W per day
-peaks at ~28A or ~700W
What it doesn't do:
-generate much at all on mixed cloud or overcast days. It yields 200-300W in those conditions from the panels but that doesn't cut it
-can't keep up to 'work' type use, ie in the trailer charging phone, running laptop, inverter running all day
Most of this information is on the basis that the inverter is running all the time including night. Night time draw is ~100-200W and begins around 8 pm till about 9 am, at that point solar starts offsetting. The overall discharge is typically 50-70A.
If I plan on heavy use I need to do a couple hours of charge (just like without solar) in the morning. If it's a good sun day I don't need to run the generator again in the evening.
If its moderate use, I can let the solar deal with it.
Hope this helps.
Bottom line for others is I think I'd equip an RV with no less than two panels, 630W if it didn't have an inverter. If I wanted it to be more self sufficient I'd go with the flat flexible panels on the roof for closer to 2,000W, that's what it would take for full time use. Occasional generator use would still be required.
The inverter eats about 50W when running.
Linear Mode
