Solar Power/Battery Question...

[Ilia Baran]

hello all,

I just bought a 25' 1979 Catalina and have been working on it for the past 2 months, I've refinished all the woodwork, power-washed, painted and now I am at the electronics part. It is a standard wiring system, with a battery selector switch, and a fuse panel.

I want to be able to use a laptop, charge my GPS/phone, and use a washdown pump for showers/cleaning occasionally, in addition to all the other obvious things (bilge pump/nav. lights). I also have an electric outboard on my dinghy which i would use rarely for landing on beaches.

Im looking at getting a solar panel, and a larger deep cycle battery. I have two similarly sized batteries now, and will want to keep them, that way, even if the dinghy battery is being used, I can still have two batteries on board.

The question is... What size battery should I get, and what size solar panel would be sufficient to keep it charged if I will only use the boat on weekends, thanks in advance for your time. I would find this info on my own, but trying to understand electricity and watts/amps/volts (even after reading for hours and hours) makes my head hurt

[djmarchand]

The cheapest, most reliable battery for house loads is a pair of 6V golf cart batteries wired in series. They are about $100 ea at Costco or Sams or a bit more at golf cart shops.

A pair of golf carts should handle your loads for a weekend at anchor. Then presuming you don't plug in to shore power at your mooring/dock, then a 50 watt solar panel will be quite sufficient to recharge the batteries for the following weekend. You need a solar charge controller, like Morningstar, but don't spend the extra money for a MPPT- Maximum Power Point Tracking controller. It isn't worth it for your situation.

David