Can I trickle charge two batteries with one charger?

[scooper77515]

I have two similar, if not identical batteries, hooked together with an A-B-Both switch.

Can I put a small jumper from positive to positive, negative to negative, and put the trickle charger on the batteries to "tend" both simultaneously? For recharging and/or winter upkeep?

 

[tpenfield]

Re: Can I trickle charge two batteries with one charger?

Why not just set your battery switch to 'Both' and connect the charger to one of the batteries. No need to fiddle with extra wires . . .

I usually will charge the 2 batteries on my boat together (i.e. 'both') if they are not too low. If they are wicked low (like after a winter of sitting there, then I will go easy on the charger and do 1 at a time.

 

[Silvertip]

Re: Can I trickle charge two batteries with one charger?

Using the dual battery switch as pointed out in the previous post is the "logical and acceptable" way of doing this. That's the way the engine does it and that's what the switch is for.

 

[scooper77515]

Re: Can I trickle charge two batteries with one charger?

I tend to put the switch to OFF so nothing is draining from the battery, such as accessories that may have accidentally been left on, or items that pull from the battery even when off. I guess a 2A trickle wouldn't hurt anything if I kept the switch to BOTH...

 

[90stingray]

Then if you must have the switch off... you will have to have jumper cables between the batteries to connect them and then go ahead and charge them up.

Sent from my DROIDX using Tapatalk

 

[scooper77515]

Re: Can I trickle charge two batteries with one charger?

Made a jumper from 4 battery clips, and a 3' 2-wire extension cord with the ends cut off. Seems to be working fine, so far.

Peace of mind, knowing that throughout the winter, if I ever get a bug up my butt to take the boat out, the batteries will be fully charged and ready to go.

 

[Silvertip]

Re: Can I trickle charge two batteries with one charger?

Have you thought about what might happen if the POS jumper clip jumps off a battery and touches metal? Does the term "arc welder" make you shudder? If you turn stuff off there should be nothing drawing current except for radio memory. That is just a few milliamps of current which your trickle charger can certainly compensate for. Just playing the devils advocate here. You only needed one jumper (pos on one battery to pos on the other). Both negatives should have been connected in order for the switch to function properly. Without that connection BAT 2 would never charge from the engine.

 

[bruceb58]

Re: Can I trickle charge two batteries with one charger?

Personally, I would never leave a battery switch on "both" or use that jumper method while charging. Buy a dual bank battery charger and leave the switch off. This way, if one battery fails for some reason, it doesn't ruin your good battery.

 

[SteveMcD]

Re: Can I trickle charge two batteries with one charger?

I have been getting away with trickle charging them both for years. I have had numerous battery failures and it has never taken out the other one.

 

[bruceb58]

Re: Can I trickle charge two batteries with one charger?

I have been getting away with trickle charging them both for years. I have had numerous battery failures and it has never taken out the other one.

If you have a battery fail, its going to bring down the voltage of the good battery. That's a fact. If left that way, the good battery will suffer due to sulfation.