Boat / battery / charging question.
 

Folks, I have a 18 foot Carolina Skiff that I am doing some maintenance on. Among other things I am replacing the rear deck and bilge and all sorts of good stuff.

What I need to know, is how large of an onboard battery charger do I need to charge two 12 volt deep cycle batteries. I am sick of having to charge them after every fishing trip. I have a pal who is going to help do the wiring, but what size charger should I be getting.

Oh yeah, I do have 2 starting batteries too.

Thanks

Paulie

So, you have four batteries total??
Depending on the size of the batteries, I would go with a 20-30 amp charger at the minimum. Also do you have an isolator between the batteries?

Wait, you have four batteries on an 18 foot skiff? You have a trolling motor you use all the time? That seems excessive - I would think three at the maximum - two deep cycle and a starting battery??

You are correct that I have 4 batteries total. I cannot say if I have an isolator between them.

More info....two batteries are in the aft section of the boat. They are used for starting, lights also powering the bilge.

The two batteries in the fore section are for the trolling motor and that is all.

Again, I don't know what a isolator is (or does) but I am willing to learn.

I also suspect much will become clear when I tear off that back deck and can see what I am getting into.....but having it in a nice big and DRY place to work....priceless....time to do it while I have it.

An isolator is put in between each battery in a charging circuit. It's purpose is to keep one low battery from draining another one down.

Pick up a book called The 12 Volt Bible. It has everything you need to know about boat wiring. Any marine store or Barnes and Noble will have it.

heres a simple diagram of how a isolator works


http://forums.pelicanparts.com/uploa...1243360964.gif

Be careful:

http://i27.photobucket.com/albums/c1...raR/SeaRay.jpg

Thats comforting!! :D

Yeah, I have been thinking that I can probably do with just 3 batteries as well as described. Again peeling off the back deck is likely to make it more apparent.

That link and book are looking like just what I need. Thanks guys.

Paulie

4 batteries in an 18' skiff? That's overkill. You only need two with a Perko battery switch. place on 1 to use for starting and 2 when the engine is off to run your electronics and pump(s). When running switch to all/both to recharge the batteries. Keep the other two batteries on a shelf on a trickle charge to keep them topped off. Better yet sell them they have a limited life. When the two in the boat go bad buy new and you will know where you are starting from. When the boat is laid up keep them on a trickle charger.

Wait you charge after every trip? What year and make is your motor?

I bet he means that he charges the trolling batteries as they would not be hooked up to the alternator on the engine. Having two trolling batteries is great and having two batteries for cranking and pumps is also smart..4 batteries is really good for a serious flats/fishing boat with live wells and heavy trolling duties.
Honestley, a small Charles Marine 15 amp charger will work fine and is pretty cheap... but the real question is where are you going to get power from to run the charger and how often do you use the boat. Is the boat trailered or left in the water at the dock?
The advice on the Twelve Volt Bible is spot on. I had it and I know more about boat electronics than I ever though I would.