Just as a matter of information. I have wired up my BC20 to run all of its, fairly minimal electronics from a 20Ah battery which I keep charged with a 10W solar panel. This last year it worked perfectly, without any further need to charge the battery, which stayed in the boat all season. The electric drains consist of:
-depth sounder
-Garmin 72 GPS
-four LED cabin lights
-three LED navigation lights (just used once for the fun of it)
-charging of one mobile phone and one tablet computer
-charging of one handheld VHF
The panel is on the cabin roof and off to one side, to avoid shading from the boom. I spent about 20 days sailing, with everything but the lights on all day long, and the cabin lights on for a couple of hours each of eight evenings. So it is possible to be independent of shore power pretty well now. The LED lights make a huge difference. On my old boat I flattened the battery in one night with a 25W anchor light. I don't have a chart plotter either, which I think are fairly power hungry, and to be honest a tablet computer is just about as good these days.
