Need Help Charging Trunk Battery

[jrath]

I have one battery under the hood and another battery in the trunk.

They are connected only from positive-to-positive with 0 gauge wire.

I have a battery charger and would like to charge the trunk battery only.

If I connect the battery charger to the trunk battery will this affect/charge the battery under the hood in any way? I do not want to send additional charge to the battery under the hood if it doesn't need it. I fear explosions.

I am hoping I can simply charge the trunk battery without disconnecting the + wire between the two batteries.

Also, do I need to disconnect the + wire from my trunk battery to my amp?

[cloud77]

Yes, you really should disconnect all wires when charging.

[tacomaguy1]

Just leave everything how it is/connected

Wont harm the front battery by charging it also, if anything it will help it

Why do you "fear explosions"? What kind of charger is it?

[Facekicker]

Providing everything is in good condition, you won't harm the front battery unless you're using a charger that doesn't have a circuit.

[SnowDrifter]

Just unhook the ground for your trunk battery. Hook the charger to the battery itself. And you are good to go

But my question is why do you want to charge only your trunk battery? Why not all of them? I'd be more concerned for an explosion in the trunk than under the hood. Gases ate trapped. Which brings up a different point- - a proper charger won't cause your batteries to gas excessively, so this isn't an issue you should need to worry about. Once again, provided you have a good charger. If not, then you shouldn't be using it in the first place

[jrath]

Thanks for all the fast responses. You guys are great.

I have a CTEK 3300 battery charger.

I would not mind charging both batteries, as long as extra wiring is not required.

Would both batteries charge if the negative poles on the batteries are not directly connected? I know they are connected indirectly via ground.

The CTEK battery charger has a sensor to avoid overcharging. However, I feared that if my front battery is holding more charge than my trunk battery than the charger may somehow detect the nearly full front battery and not fully charge the trunk battery.

[Wicks]

You could run into more issues if you only charge one battery and then interconnect it back into yours car's electrical system repeatedly.

You'd be connecting a resting battery with a freshly charged battery. That may only be a difference of ~0.5V but at a battery's capacity that's a lot.

Plus you'd be charging the under-hood battery in this scenario anyway when you reconnect the trunk battery.

Go ahead and charge everything connected and it will be just fine.

In your car ALL the negatives are tied together. ALL the positives are tied together. Doesn't matter if you are using straight wire or the chassis. Its all the same.

My only concern would be to avoid putting a lead-acid battery in the trunk since they are prone to leak gas which could flow into your cabin.

Make sure its a sealed battery and you're all good.

[jrath]

Thank you Wicks.

The batteries are Kinetik HC1400's.

I will just leave everything connected as is and charge both batteries simultaneously.

[cloud77]

That charger recognizes battery type, (agm,lead acid), amp hour capacity, and health of the battery upon placing it on the terminals. It charges at only about 4 amps, but is called an intelli charger for a reason. It recognizes the state of the battery its connected to and provides maintenance accordingly. If your positive lead is still connected to the front battery it will not recognize the specs of the battery you intend to charge. Opposite polarities attract, and your front battery is grounded. Most of the trickle charge of 4 amps will be lost in the relay of your positive lead to the front battery. You will find that you will have the charger on the battery for hours and hours and the light never goes 100% because of this.

So...Just disconnect everything and you will get a correct charge.

[mikeg321]

That charger recognizes battery type, (agm,lead acid), amp hour capacity, and health of the battery upon placing it on the terminals. It charges at only about 4 amps, but is called an intelli charger for a reason. It recognizes the state of the battery its connected to and provides maintenance accordingly. If your positive lead is still connected to the front battery it will not recognize the specs of the battery you intend to charge. Opposite polarities attract, and your front battery is grounded. Most of the trickle charge of 4 amps will be lost in the relay of your positive lead to the front battery. You will find that you will have the charger on the battery for hours and hours and the light never goes 100% because of this.

So...Just disconnect everything and you will get a correct charge.