As noted a while back, the solar panel I have on Blue Opal wasn’t working well with the Votronic MPPT solar charger. The panel I have is a 55 Wp panel, and the testing I did led me to the conclusion that it basically can’t put out enough voltage that the Votronic can buck down to a ~13-14V level to charge the batteries. Combined with the age of the batteries, and they basically don’t stay at a good voltage level any more (and they drain fairly quickly).
Whilst browsing around the other day, I noticed that Renogy EU had a sale on, and they had a 200 Wp flexible solar panel going somewhat cheap – 180 EUR, shipped. As a comparison point, SVB have a 155 Wp Phaesun panel (flexible too) at 470 EUR. I figured it was worth a punt; at worst I’d have to resell it, and I could probably sell it for what I paid for it and the buyer would think they got a bargain.
Well, with a bit of crimping (and I’m loving the new bootlace ferrule crimper that I have, Preciva brand, 0.08mm sq to 16 mm sq) and bodging, I wired in that new panel this weekend. It spans the cockpit, and makes it awkward to get out of the cabin, but it also provides ~23 V on an open circuit. With that input fed to the solar charger, I was seeing a lovely 14.2 V on the output of the solar charger, and about 2 – 3 amps (measured with a clamp ammeter, not a shunt) being pushed into the batteries on a cloudy day.
So, the Votronic should be happy now, and the battery bank should stay topped up for summer at least while I do research on the lithium battery side of life.
I’ve also got some wiring to re-do now; there’s quite a few connections on Blue Opal that were done into terminals where I could only stuff the bare wire in and crush it. With a bootlace ferrule crimper available to me now, I can re-do all of them so that they’re easier to work with. I also need to move the solar charger output over on to the starter battery, and let the DC-DC charger shunt power into the house bank – it should do that quite happily, as the starter is a) new, and b) almost always fully charged.