Solar in a Covid world….
We were in a private campground, near home in Central Illinois, waiting to see if the whole virus thing winds down a bit as states reopen as well as making repairs, adjustments and upgrades on the RVs before, hopefully, heading out west to higher, cooler altitudes for the summer. Plans, right? We could go home to swap tools and RV stuff from the garage and did make a foray or two into the house with PPE gear on. Our son and his family share our house with us and two of them are front-line healthcare workers. Since we are in the 65+ club, we simply can’t move back in right now. We can’t get careless with exposure to Covid.
When we started RVing, we were just taking long vacations (we were retired). Then snowbirding became a thing. We had been seriously discussing going full time or near full time (with small home base somewhere south below the snow belt), but we have way too much junk at home to make the transition. Our plan had always been to travel a few months, then come home and get rid of stuff before hitting the road again. We left home last November for the Gulf Coast and it looks now like we won’t be home to live until next spring; well over a year in our RV.
We are isolating with our daughter and her family in a small private park in central Illinois before heading out west. RV#1 (ours) already had 800 watts of solar from an install we did a year ago. RV#2(theirs) had no solar, but it did have over 500 amp-hours’ worth of lithium batteries installed. It also has a 1200 watt modified square wave inverter/charger (inadequate). The battery bay was on the right, the inverter on the left. They wanted solar so we could boondock together and get a bit closer to nature.
They ordered the solar panels and equipment from ContinuousResources.com. (Affiliate link) We ordered four 200-watt panels, brackets, cable, a combiner box, and a mini-circuit-breaker box, all of which arrived quickly, and thankfully considering the virus was already in full swing around the country. What we didn’t order was a solar controller. Somehow, in the confusion and rush, I managed to convince myself the controller he salvaged from the solar install on their previously owned RV would work. And, well, it would have worked, sort of… Technically it supported enough volts and incoming amps, but couldn’t output the wattage. It just wouldn’t have let anywhere near 800 watts of power get to the battery. We discovered this just before starting the install and so after a short panic, quickly figured out which controller and found one we could get quickly. Fortunately, it arrived just in time as we were working our way down from the roof with cable, toward the batteries.
The design included the possibility of adding more panels in the future, so the wiring and combiner box allowed for up to four more panels (though on this RV, that would be tight). We positioned these first four panels forward and away from the AC’s and vents as possible for the least amount of sun interference. Based on previous installs we had done; we chose to use ½ inch by 1 inch well nuts with ¼-20 stainless bolts for mounting. We set the panels in place, marked the holes, moved the panels away, and drilled out the holes. We intentionally drilled the holes a bit small and hand adjusted with a Dremel until the well nuts just fit in snug. We put butyl tape around the well nuts before placing the brackets (panels) and put self-leveling sealant all the way around the brackets and over the bolts.
For the roof-top wiring, we used 10-gauge solar wire (red/black) and connected them as two sets of 
serial panels, with inline fuses and combined in parallel in the box. Thus, at full sun exposure, we can expect around 45 volts and almost 20 amps headed toward the MPPT controller.
From the combiner box, we ran 4 AWG cable, down the inside of the back cap. Yes, that is probably a size larger cable than we needed, but because future expansion was a possibility as well as the fairly long run, we opted for that size. Because we wanted to put the combiner box on the right side as was the same position of the ladder, the box went several feet forward of the ladder and we extended ¾ PVC electrical conduit back to the rear cap. We put the split wrap on the entire length of the down run and clamped and tie-wrapped as necessary all the way to the battery box. Then the real fun begins…
I didn’t really get much of a chance to see this RV when it was new. Some work had been done on it, for example,
to change out the lead-acid batteries to lithium. But they were, as told, in theory, connected exactly the same way as the lead acids were done at the factory. There was a block fuse on one wire leaving the battery (to feed most of the 12V DC for the house. There was a separate breaker for the wire going to the hydraulic motor for the jacks. There was a wire (4/0) going to the Inverter that had NO FUSE! While the inverter has its own internal breaker – fuses at the battery are there to protect the cable going FROM the battery to a remote device. Not having a fuse/breaker on the inverter cable means there is no way to remove power to the inverter except getting out a wrench, and it also means if someone were to run into the RV at the inverter side – the full current of the batteries would be available for sparks, flame, and ball lightning. One must still get out a wrench, but it is just to loosen the fuse, but at least without leaving wires hanging. An actual Inverter power switch is on the todo list as is, someday, a bigger better inverter.
So, we then installed a piece of plywood in the back of the battery bay to mount everything. Secured a large fuse holder, a ground bar, the new solar controller, and the mini breaker box, and began wiring. We scrounged up spare cables and built the ones we needed. (I have a hydraulic crimper and had ends left over from other solar jobs). Once we had all the parts ready and a process lined up, we turned off the inverter and coach power and proceeded to replace cables as needed and reconnect everything. The 4-gauge wire was a bit of a problem as the solar controller wasn’t built for that heavy a wire, so we trimmed those wires down a bit to fit. The controller is just big enough for the 4 panels, so a new controller would be needed if they added panels and a bigger controller would have more connector space for the 4-gauge wire. When we were all done, the sky was a fairly heavy overcast and the batteries were mostly charged (they had been plugged into camp pedestal), but they still were putting out 254 watts (18 amps) into the lithium batteries.
All told, it was a successful install. It took two of us about two and half workdays working between rainstorms. We are now headed out west for some boondocking.