Getting the solar panels dialed in

When we purchased Lutris she had a couple of 55W solar panels that came with her. Once we had gotten her to Seattle, it was apparent that the charge controller that turns the power coming from the panels, into something the batteries can use, had died.

I wasn’t in any hurry to get it sorted because 110W of solar didn’t sound all that productive, especially during a Seattle winter. However, with the approach of spring and the promise of longer outings in the upcoming season, I wanted to get it all going. It’s my intention to add about 640W of panels (2 x 320W) at some point to the arch. The reality is though, that until we make the big left turn, having that much power will often go wasted. So I think I might just add a couple of smaller panels (160W) in the interim and hope that the technology offers up something new and more efficient in the next couple of years. That should allow us to get more power out of the available space. The smaller panels won’t be wasted, as we’ll probably move them off the solar arch, and to the lifelines on the aft deck of the boat, giving us what should be well over 1000W of solar generation.

In the meantime, the controller needed replacing and with an eye to future additional panels I decided on the Victron BlueSolar MPPT 100/50. This is quite a fancy piece of kit, but it will allow for up to 700W of solar, and can charge the batteries at up to 50Amps. I think we’ll eventually end up with 2 of them, both for the additional capacity, and as a failsafe for when one breaks down. One cool feature of this controller is the ability to send data to the iDevices aboard, including the full history of the it’s output. I didn’t think I’d care about it all that much, but my inner data nerd started doing a little dance when I could see exactly what everything little thing I did to the panels did to the output. I have a feeling that I’ll be able to spend entire days just going over solar output.

Installation

The installation was pretty straight forward, thanks to the pre-existing controller. I ran new 10AWG wires to the panels since I was going to be hooking them up in series, instead of parallel. Then used the existing wiring through the boat to our “alternative energy locker” (where our wind and solar controllers hook to the battery banks). For now the panels don’t have any circuit protection, but I’ll be remedying that shortly with some dual pole switches. So the panels wire straight to the controller, and then from there through a 40AMP ANL type fuse to our house bank. The bluetooth dongle hangs off the controllers network port.

Even with these little panels (by today’s standards), I was impressed to see that the controller was able to eek a lot of power out of them, even in the iffy Seattle spring sunshine. I was getting 61W with barely any sunshine at all, and later was seeing 105W (nearly rated output) at about 1PM on a sunny day.

Lutris, with her (rather large) solar arch / davits has a distinct advantage to mounting panels in a place that will get very little shading. The only potential shade comes from the wind generator, but I think that can be mitigated most of the time. I think with a bit more power up there, we can be totally self sufficient on solar alone, but we see it as part of our overall energy generation plan. We can create power for our 645AH bank with our diesel generator, by running our engine through the alternator, with output from our wind generator & solar panels. It’s nice to feel like we’ve got a solid approach for getting this done once we are living on the hook.