On board battery charger

[syd]

Well i told the wife i wanted Santa to get me an on board battery charger. Having never had one i have a few questions. My boat is a 17ft aluminum Bass Tracker. The trolling motor batteries are up front and the battery for the motor is in the back compartment with gas tank, bilge pump etc.
My question is this. Can i get one that will have enough cable to hook up all 3. Will i need to get additonal cable to hook up all 3. Would i be better off just getting a 2 bank for the trolling matter batteries? Plus do they have an indicator on them that will let you know if you have a battery going bad.
And of course any information on which to get would be helpful.

[bassboogieman]

You won't find a charger with leads longer than about 4' so they won't reach both compartments. You have a couple options.

3-bank would do all your batteries, but you would have to splice the leads to either the crank or both trolling motor batteries, depending upon where you locate the charger. If you go that way, use same gauge cu wire and solder the connection, tape, coat with silicon and tape again.

Do you use the outboard often? Many boat manufactures and anglers don't bother with an onboard charger for the cranking battery as it's charged from the outboard. You could suppliment that charge with a portable charger when needed, and only use the onboard charger for the T/m batteries.

Or you could buy 2 OBC and mount a 2 bank (10/10) upfront for the T/M and a single bank (5a or 10a) and put it near the crank battery and avoid all splices. You'll spend a little more for two units, but that's what I did (3 bank for the 36v T/m and a single charger for the cranking battery). I fish a lot of electric only water, so I need to charge my cranking batter after every trip, having the charger on board is very convienient.

Most chargers have indicator lights to indicate level of charge but will not give indications of a bettery going bad - other than it not taking a full charge - for that you need a hydrometer.