Solar Power System for an RV

Been running an Outback | Solarworld Sunmodule system on our RV for a couple of seasons now and realized that I'd never shared the finished project. 99.5% of our camping is off-grid (primitive) dry camping in the national forest so it made sense to go a bit overboard. Well, it actually didn't make sense financially but it sure was fun

Initial ramblings started with this thread from early 2013
Solar panels in parallel - Partial shading question | Survival Forums
and this for my own reference (has become a popular Google hit)
Battery Bank Wiring Diagrams - 6 Volt - 12 Volt - Series and Parallel | Survival Forums

The roof of the travel trailer is pretty limited in space and layout so I had to do the best I could with smaller panels. A future plan includes mounting 2 larger (260W +) panels to the side of the trailer and swinging them up into position when in use. I ended up going with 4 Solarworld sunmodule (mine were made in Germany) panels at 140W and 2 of the same make at 80W. We've run all of the panels to a terminal block (combination of series/parallel) in the air conditioning housing. Total installed panel wattage is 720W.



The DIY combiner box runs down through the refrigerator vent and enters the Outback FlexMax80 MPPT charge controller which is buried in a front bulkhead storage area of the trailer. Proper ventilation was provided. All loads/charging display near zero today as we're in idle and fully topped off with little demand.



Since the charge controller is hidden, we went with the Mate3 control panel which allows us to monitor, log and control every aspect of the system. Its a rather full fledged SCADA system which lets us view logs, hi and low stats and day by day charting, etc.



Most of an RV is 12V DC but when 120V AC is needed, an inverter is needed. The Outback 2812 VFX mobile is both a DC -> AC true sine wave inverter and also a 5 stage AC -> DC charger. With 2800W, we're able to run coffee makers, a microwave and could even run the air conditioner for brief spurts if needed although we typically don't run the AC (would love to remove it and add another panel in its place). You can see the breaker enclosures and safety isolation devices in this image.




The nice thing about an Outback system is that every device can be networked to a central hub and the Mate3 which allows them to all work together as efficiently as possible.



We've installed 3 shunts which allow the system to monitor loads coming in and out from various sources. This current is tracked by the Outback DC Monitor



The power is stored in a battery bank which was upgraded from the original single 12V battery that came with the trailer. We're using four 6V deep cycle batteries: Trojan T-105RE in Noco dual boxes on a custom welded tongue bracket. Note the Outback temperature sensors which run back to both the inverter and the charge controller for charge corrections based on ambient and battery temps.



We've also installed an AC 'out' breaker with a twist lock connection on the outside of the trailer. This can be connected to the transfer switch on our house which allows us to run some small (think comfort like lights, coffee maker, etc) things in the event of a short term power outage. The project was pretty fun and although it's never going to 'pay for itself', it does allow us to journey out and stay out for long periods of time. We never run out of power and the RV isn't really ever hooked up to household AC power even when parked next to the house.

This system was 100% designed and installed by me. I'm sure there are better ways of doing this but I wanted to learn how

 

Nice to see the completed Project.... Well done....

 

Nice write up and very technical lay out! Well done!