Charging 3 batteries?

[arnieb]

Hello group,

I'm hooking up the batteries in the boat I bought last year. I have a 1988 135 Mariner. Can or should this engine charging system be able to charge all 3 batteries when running? Seams to be alot of load for the alt? I was thinking of installing a battery isolator on a switch to charge the aux batteries when I need to.

Thanks
Arnie

 

[Boatist]

Re: Charging 3 batteries?

Look in your onwers manual an if your alternator is 30 amps or more I would set up to charge all.
If it less then I would question if it worth it. It would be charging full bore a lot of the time if you have a trolling motor. That can cause a lot of heat in the alternator and diodes.

If you have not keeped the batteries charged all year since you bought them then I would check them very good before installing them. Not keep them charged does a lot of damage.

I like to charge thru a battery isolator also but with a isolator your really do not need a battery switch unless you want to be able to start off of different batteries. If you have a internal voltage regulator in your alternator then be aware that isolator output can be .7 volts lower than without an isolator.

If you get a battery switch then get a make before break type and never turn thru off with motor running unless you want to buy a new alternator, voltage regulator, or Diode Block.