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( Mika) wrote in :

Are small ~ 5 watt solar panels any good for providing little charge
to prevent discharge of the battery when the boat is not used for a
week or two? Or should I get a bit larger panel in 10-15 watt range ?
Would you consider these small panels as just toys?

Expect to use the alternator to do most of charging when the engine is
running. Only one 60 Ah deep-cycle battery, used to start the engine,
log, depth, navigation and interior lights, radio etc. No power-hungry
appliances onboard our 27ft sailboat.

Panel would be in fixed position facing south, and being in latitude
60 degrees north we do get lots of sunshine in summer

Thanks in advance for any comments!

Mike

My rule of thumb is that you get 1/2 of the rated capacity of a solar panel
when they're used to charge batteries. Thus you'll only get 2.5 watts,
which is for all intents and purposes, nothing. I'd go wild and crazy and
get a 10-15 watt unit.

-- Geoff