Ask SAIL: Alternative Power Priorities
Jeff Wrigley of Annapolis, Maryland asks:
I want to move aboard my Alberg 37 next summer and cruise up the East Coast from Annapolis to Maine. I have two 90AH house batteries and a 60AH engine starting battery charged by an 80AH alternator. I plan to anchor out most of the time. My boat is simple and my electrical demands are otherwise low, but I do like cold drinks, so I want to be able to run my fridge, which draws 2 to 4 amps, without constantly running the engine. I can afford either a solar panel or a wind generator, but not both. Which would you recommend? My issue with solar panels is the space they take up. I hear it’s best to mount them on a radar arch, but the prices I’ve been quoted for an arch are painful.
Nigel Calder replies:
East Coast winds in the summer, especially in Maine, tend to be light. A wind generator therefore will not be of much use. I would go for the solar panels. Do you have a bimini? If so, you could put semi-flexible panels on top of it. Or you could carry flexible panels rolled up in the quarterberth and lay them out on deck when needed. The advantage here is that you can move them around to keep them out of the shade. Probably the most efficient flexible panels are those from Solbian, though they are pricey.
My guess is given the power demands on your boat and the limited output of solar panels, you can get away without a voltage regulator as long as you don’t leave the panels connected for days at a time without any load on the system. This will save you some money, but you’ll have to keep an eye on the battery voltage when it’s sunny. Whatever you do, install a fuse where the panel’s positive cable connects to your boat’s DC system.
