When we first set eyes on Galapagos, one of her many charms was a pair of solar panels mounted, fetchingly, upon the hard dodger. Like any relationship that begins at the hormonal level, we overlooked some of the shortcomings that these solar panels might possess. For example, they were only 60 watts. Or that one was only putting out three volts.
Still, the mounting hardware was well placed and the all important wiring into the electrical system was good. So, like any new and budding relationship, we set about to change the object of our affection to suit our ideal.
For this project, I chose to replace the existing panels with the Renogy Monocrystalline 100 watt panels. This selection was made in part because of one of the cruising blogs we follow, Sundowner Sails Again. They installed the Renogy flexible type panels onto twin wall polycarbonate panels. Also, the reviews on Amazon for these panels was glowing. We paid $320.00 for two one hundred watt panels, a 30 Amp charge controller and some rather nice but unnecessary electrical connectors. Check em out here: Renogy Solar Panel Bundle 200Watt: 2 100w Solar Panels
Since the old panels were the rigid style and the mounting hardware on our dodger was set up for that, I chose that style. However, I may buy a pair of the flexible panels and place those on the stern as Sundowner did or even on the foredeck when at anchor. Supposedly you can walk on the flexible panels which could be useful on our dodger as occasionally we have to climb up there to mess with the mainsail. Still, it seems unwise to walk on solar panels.
The Renogy panels come with a small junction box mounted below which contains the blocking diodes and terminal connections to short cables fitted with MC4 connectors. Two points here.
- The wires to the terminal board in the junction box were crimped but not soldered. I went ahead and soldered the connections; it just seems like cheap insurance and I was a little disappointed that it had not been addressed during manufacture.
- The MC4 connectors seem to be a reliable, sturdy method of hooking these thing up. However, they are large and I would not drill a hole into my dodger large enough to pass them through. I ended up cutting them off and splicing on a length of 10/2 cable to the factory cable and then pushing that through the existing holes used by the old solar panels. That was then sealed up with Life Caulk.
The original panels had a controller mounted under the dodger not too far from where you see the black windshield wiper motor on the left in the photo above. I wanted to mount the new 30 amp controller inside, away from the elements and near where I could check the output along with the rest of our electrical devices. In a concession to the facts at hand, I re-used the old electrical cable that leads down to breaker panel and spliced all the cables together and ran the un-regulated voltage down stairs. the cable leading down to the breaker panel is 12/2 which should be fine for the maximum of 11 amps that these two panels can put out. Snaking a larger cable through the existing raceways and holes was going to be a pain.
Galapagos has an old but pretty well thought out breaker panel just next to the engine room and workshop. The old solar system ran the regulated input to a 20 amp breaker on that panel. (there are actually two, one for the dodger panels and one for panels mounted astern) I was able to place the new charge controller on an unused portion of the panel, and then run the regulated output to that 20 amp breaker. This allows me to switch the charge controller in and out of the battery circuit with a simple flip of the breaker.
No project is ever complete without dressing up the wiring. For this, I used some simple cable raceway with an adhesive backing that I cut to fit. It isn’t perfect but it looks a sight better than a bunch of dangling cables.
I almost undid all of this work when I thought I would make sure the conduit would stay in place by driving a small screw into the base. What I actually did was drive a screw right through my freshly spliced cable! Fortunately, the screw missed all wire and just barely nicked the insulation of the black wire.
So, now the question is, how well do the panels work? I haven’t really had an opportunity to put them to a hard test yet. Melissa and I spent a few hours sailing and anchored out on Vashon Island this past Sunday but that is hardly a test; We just don’t have a lot of current demands until the new refrigeration unit is installed. Hopefully we will have our holding plate delivered next week and then we will be able to see if the two panels will be able to keep up.
The solar panels represent an important project completed prior to our Vancouver Island trip this July, The dream is to be able to anchor in a seculded cove for four or five days without using the engine to top off the batteries. I have spent a lot of time insulating and sealing the icebox and if the refrigeration unit is as efficient as advertised, we hope to live off solar power exclusively.