Charging Dual Batteries Question

[emoney]

Ok, so this is my first boat with dual batteries, hooked up via an a/b switch. The question is pretty straightforward so please forgive the ignorance. But, with the 1/2/Both switch, am I still charging each battery individually? Also, is there a risk of problem with using a "top off" charger on one battery while using a trickle charger on the other? Both chargers are considered "smart" chargers that shut off when reached 100% (or so they say), but I want to make sure I'm doing the charging the correct way.

If not, do I just put the overnight charger on one tonight and then do the other tomorrow night?

 

[Augoose]

Re: Charging Dual Batteries Question

When you run the engine with the selector on "both", it is running off of and charging both. When the selector is on 1 or 2, its only running/charging off of that one battery. As for using a charger, I'm sure someone else will chime in, but if you want to use both chargers at the same time, I'd set the selector to off, then connect each charger to each battery individually.

 

[Silvertip]

Re: Charging Dual Batteries Question

No need to use both chargers. Set the switch to BOTH and connect the charger with the highest output to the COM terminal on the switch. Both batteries will be charged.

 

[Boatist]

Re: Charging Dual Batteries Question

If you want to use both chargers then set switch to off or 1 or 2 but not both. As long as they are smart chargers it wil work fine.

What Silvertip said will also work but with causion. You can put in both and charge on the common on the switch or just connect to either battery and it will work. However this should really only be done if batteries are the same type and same age.
The problem is if batteries are different types or differnt ages or one has a dead cell it can kill both batteries.

 

[emoney]

Re: Charging Dual Batteries Question

luckily they're both from the same set of parents, purchased and installed at the same time.

Thanks to all for the responses. I had a sneaky feeling that 'both' would allow both to charge, but I never trust my own instincts when it comes to matters I know little about. Does it take longer if you put the charger on say the front one, and have the switch at "both"?

 

[Boatist]

Re: Charging Dual Batteries Question

It should take the same amount of time. Anytime you are charging 2 batteries that have some discharge then it will take longer as it has to supply the current to both batteries. If the same type and age then half of the charger current will go to each battery if both batteries are good.