Is it safe to charger two batteries while they are still in car?

[Robert 9]

I have front and trunk batteries in parallel and want to know how to charge them together without taking them out of the car if its possible. I don't want to just hook charger up while everything else is connected and burn out an amp or anything else electrical in the car. But if its safe to do it then that would help instead of going through the whole routine of taking each one out and doing them one at a time.

[S.DeYoung 967]

I have front and trunk batteries in parallel and want to know how to charge them together without taking them out of the car if its possible. I don't want to just hook charger up while everything else is connected and burn out an amp or anything else electrical in the car. But if its safe to do it then that would help instead of going through the whole routine of taking each one out and doing them one at a time.

If you charge them seperately you should be fine.

[altoncustomtech 773]

I cannot imagine a single possible reason why you could not do this. Hell, I've done it many times, as I'm sure many others have. If there's a no no reason for doing so I'd like to have it explained in excruciating detail, lol.

It's not going to hurt any equipment, nor should there be any effect on charging the batteries together.

[Duran 387]

Just throw them on your charger...nothing will happen to your amp, your charger will charge at 14.4 volts, with even less amperage than your alternator, what could it possibly do?

[Robert 9]

I needed the peace of mind with your answers, hell if you only know the luck I have even the tiniest easiest things in all the world tend to turn out to be mountain climbs for me lol. Thanks guys

[Shogen 325]

good to know...

[CrazyKenKid 64]

problem solved!

[nem 2,019]

I like to use a battery tender.

http://www.batterytender.com/

[jcarter1885 995]

I like to use a battery tender.

http://www.batterytender.com/

good link, I need to get one of those ASAP!

[Robert 9]

I have this,

http://www.autozone.com/autozone/accessories/Schumacher-75-20-10-2-Amps-speed-charge-automatic-battery-charger-engine-starter/_/N-2604?itemIdentifier=58755&_requestid=4686535

I just went out hooked it up to front battery and in about 4 minutes it was done. I guess maybe my alternator has been do0ing a good job of topping them off. Before I had the secondary battery I used to take the main battery off to charge every once in awhile and it would take about 10min to charge by itself. I'm still in the caveman stage of learning so I'll understand this better as time goes by.

[shizzzon 461]

i'd say this-

If the rear battery is not separated from the front battery when car is off, then they will see each other obviously.

You can charge more than 1 battery of like specs together provided they have always been together from the getgo.

This is assuming that both batteries ALWAYS are on the same level of discharge\charge before recharging.

Now, something i've noticed -

When trying to charge starting battery with it still connected.. I couldn't get it to receive steady current over a period of 3 minutes or so.

Things in the car were "stealing" the charge. I never diagnosed what was taking it so i just disconnect the ground off the starting battery then charge it. Everything is good then.

Without some form of isolation, i would disconnect the ground off all batts.

It's not necessary but in my situation it was.