Lisa Jawork of Toledo, Ohio, asks:
“So far I’ve only used my 24-foot Bristol Corsair for daysailing, but this summer I’m planning to take some weekend cruises. I want to be sure I have enough power, not only for the battery that currently feeds the cabin lights and instruments, but also for a second back-up battery I carry for miscellaneous uses. I’m thinking about getting a solar panel to help charge both batteries, and I’ve also purchased solar lights for the cabin. Do you have any other ideas that can help maintain battery life? I don’t have a shorepower connection, so I’d like to know of any other cost-effective solutions.”
Nigel Calder replies:
The answer is basically wind, solar, or both. To get the proper balance, you need to weigh the hours of sunlight against the seasonal wind speeds typical for your cruising area. You must also determine whether you have sufficient surface area for the solar panels to produce a meaningful output. I always plan on getting the equivalent of around 4 hours a day at full-rated output. In other words, one 30-watt solar panel will produce 120 watt-hours a day, or about +/- 10 amp-hours at 12 volts. You should also work to conserve energy, and items such as your solar lights are a key part of that effort. LEDs are also very effective.