Battery Chargers

Having said those things, it should be somewhat obvious that it is extremely important to use a proper charger to do the job of recharging your batteries!  Most chargers that are designed to charge you car batteries are not designed to charge your boat batteries: they just don’t always completely shut down.  And how often do you think that you can remember to unplug that cheap charger when things “look about right?”  From what I have read, a 3-stage charger – one that will totally shut off when the battery has reached full charge – is your best buy. 
Without all the chemistry and physics involved, batteries will do best on a regulated diet of amperes and volts served up in the right amount… and in stages.  There are three stages: 1) bulk, 2) absorption and 3) float.  The bulk stage is where a battery is brought up to about 75-80% of capacity.  Absorption is where the voltage is constant but the amperage is tapered while the battery is “topped off.”  And finally, the float stage is where the voltage is just enough to keep the battery from losing any charge.  I’m sure that you are aware of this, but a battery can lose – depending on how and where it is stored – up to 30% of its charge per month – just sitting around the house or garage!  And there are all kinds of things that affect battery charge and loss thereof (like temperature, humidity, state of discharge, age of battery, etc); most of us never consider any of them.  Does size really matter?  Well… in a matter of speaking – yes!  Try to get a charger that is rated at about 15% of the battery’s amp-hour rating (a battery with a 200 amp-hour rating would suggest the need for a 30 amp charger).  I recommend the Dual Pro Professional Series 2-Bank Charger, 15-amp/Bank PS2 (see/click on photo above).