Solar panels

[noby]

[ QUOTE ]
but for winter you'll either need to swap the panel from one battery to the other once a month, or arrange a double diode system to spread the charge. Paralleling the batteries would work, but if one should get a bad cell, that would bring both down, so it's not advisable.


[/ QUOTE ]

Hi. Just thought I'd jump in here. Because I don't have any way of charging from my engine, swapping the panel from one battery to the other seems to be the system all year round (I've only recently acquired the boat, and I'm just starting to get my head around the wiring). Can you elaborate on the double diode system?

 

[jimbaerselman]

Negative goes to both batteries, probably via a negative bus bar.

Positive is split into two supply lines. Put a diode in each line. Consult an expert to find the right diode specification; has to work with up to 20v, 5a max (I'm not into diode specs, so I can't take this further).

The panel supplier will have one diode fitted (to prevent discharge from battery through the panel when there's no light) and they should tell you the spec, even supply an extra for you.

Fit a fuse to handle shorts.

 

[noby]

Aah, as I suspected so. Thanks.

 

[PeterGibbs]

From your bio, your boat is in Weymouth. Lots of alongside power - unquestionably the best solution for the winter months. Fit a mains battery charger - costs half that of even a small panel.

For the summer, if you're anchoring a lot and taking pride in sailing everywhere, the logical solution is to fit another service battery. Your engine power output so dwarfs anything off a panel, it is likely to keep you alive.

PWG