How to Charge Multiple Batteries of Different Voltages

Question:

I am doing a similar set up it my RV. Hooking up two 6 V to make 12 V, and then hooking up to the original battery that came with the RV which is a 12 V. My concern is I am running them all off of one charger but the amp hours between the two 6 volts and the one 12 volt are different. Do I need to be concerned about that?

asked by: Matt J

Expert Reply:

When charging batteries in a multi-battery setup it is better to charge each one individually and disconnected from the ohers.

In the case of two 6-volts wired together in series you can keep these connected together and charged as one if they are both the same as far as battery type, amp hour rating, and battery age. Otherwise mismatched batteries will not charge evenly and become out of balance giving you less power out put in use.

I would not charge all three batteries together - you will not get good results. When it is time to replace the 6-volt batteries I would by the highest amp hours you budget allows being sure to get new identical batteries, and then toss out the 12-volt odd battery that you have.

Depending on the total amp hours a good choice of chargers would be the NOCO # NOC64FR which will let you charge your 12-volt battery at the same time as the 6-volt pair.

expert reply by: Adam R