When we bought our (second) Airstream trailer back in 2010 we had a solar system installed by AM Solar in Springfield, Oregon. We knew (1) we’d be using the trailer off the grid often, (2) we needed electricity to live and work (and blog), and (3) we didn’t want a noisy generator. That solar system has been wonderful - supplying plenty of energy for us to stay in remote areas for many days with no power except what we could gather from the sun.
When we bought Airship in 2014, we knew we wanted solar on it as well.
The power situation on the boat is considerably different than on the Airstream. First, the boat has a 5KW Onan diesel generator built in that runs off the boat’s fuel supply. As generators go, it is quiet, efficient, and easy to use. But, when we’re at anchor, we don’t really want to be running the generator all the time. So, we doubled the size of the house batteries (to 440Ah) added a 2,800W Inverter (to allow us to run AC loads without running the generator) and added two 140W solar panels and a charge controller to help keep the batteries charged during the day.
Solar panels, first round:
What we’ve learned in the 300+ nights we’ve spent on Airship is that we want more solar power, and we want more battery capacity. Unlike the Airstream, Airship’s refrigerator is not propane-powered, so you’ve got a fair amount of energy being used all the time to run the refrigerator and the deck-top chest freezer we added. Adding the other miscellaneous loads to that, we found that the 280W of solar we’d installed never “gained ground”. It simply slowed down the rate at which the batteries went down during the day. If we started the day at 100% battery capacity, we’d be down around 75% by the end of the day, even with the solar helping out. Since you don’t want to run AGM batteries below 50%, that means we were using up about half of our useful capacity during the day even with the help of the solar.
Usually, then, we’d end up running the generator for an hour or so at the end of the day, and another hour or so first thing in the morning. Even with solar, our batteries are basically good for 24 hours at anchor without running the generator under normal conditions.
Looking at the roof of the boat and the specifications of new solar panels, we realized we could replace the two 140W panels with two 260W panels and almost double the solar power. Of course, bigger panels require bigger wires, so we’d need to re-run the wiring from the roof of the pilothouse down to the engine room where the solar charge controller is.
And, since bigger solar panels mean more power, we’d need to replace the solar charge controller which wasn’t big enough for the new panels. We opted for 2 separate charge controllers to make the system more efficient even with the partial shade we often have on one panel or the other from the radar antenna.
And finally, using the new charge controllers meant we’d need a new display, control panel.
So, we ended up with a pretty big project removing the old solar system and replacing it with new. And, since (ahem) one of us had his right arm out of commission, it was up to the other one to do the vast majority of the actual work.
The new solar panels JUST fit...coming right to the edge of the pilothouse:
Leaving room for the center hatch to open just fine:
For comparison, previous (smaller) 140 watt solar panel on the left (note the amount of space between the edge of the pilothouse and the panel, and the panel and the center hatch):
New (much larger) 260 watt solar panel on the right (note lack of space around new panel):
Running new wires down through the mast:
Wiring the two charge controllers in my slippers, like a boss (shut up):
It's a pretty cramped workspace down in the engine room, so we put enough wire on these so we could bring 'em up top to work on them, and then just coiled it up and zip tied it after we installed them (this is apparently called a "service lead"):
It took about two days to finish the whole project. Everything seems to be working great, although we’ve only really been able to test the system in the marina. Yesterday morning before we left Cap Sante and headed for LaConner, at 9am with a still-low sun we showed to be putting 15 amps into the batteries. Woohoo!
At the moment it's gray sky and pouring rain, but we're in a covered slip now so it makes little difference as far as solar is concerned:
We're in LaConner having some electronics upgraded and some carpet replaced with Amtico (the flooring we already have throughout most of the boat). I brought the boat from Cap Sante yesterday morning and Kevin drove the truck over and met me at the dock. (Yay, I soloed the boat!) It was pretty windy, with quite a bit of chop (even in the channel) but it was a relatively chill little hour-and-a-half cruise.