Batteries

[jl.kauai]

Recently purchased a Ram 2017 Promaster Van. Unit has two deep cycle 12 volt AGM batteries. Has anyone changed these over to two 6 volts in series. Are you glad you did this conversion. Thank you. John

[A32Deuce]

Depends on what you plan for camping. I have 2 AGMs and wouldn't change since the delivered bats in the unit had 1 go bad while on the road and 1 good. Just disconnected the bad one. But I don't do long time boon docking only occasional overnight stops.

[Persistent]

Most likely I would keep the two AGM's.
A pair of AGM's that cost $0 is better than a pair of flooded Cell batteries that cost $200.

If you are worried about the AGM performance, have them load tested. Or better yet have them 20 hour discharge tested.

If the 20 hour test amp hour rating is more than 80% of their new rating, they are good to go. Fully charge them before storing the rig. Disconnect them for storage of more than two weeks. They may last another 10 years.

Do you need more capacity than the two AGM's are rated for?

I wish you good luck and happy trails ahead!

[jl.kauai]

I am use to two 6 volts from previous rig which seemed to work well. Only inverter was for TV and Sat. Box. Then kept them up with 300 watts of solar. Now I can only have 190 watts due to space on roof..Just wondering if someone with Ram Promaster had changed them out. Batteries are still good and keep them charged by solar or driving. Have a 2.8 generator also. Thanks for reply’s. John

[Gary RVRoamer]

Merely comparing 12v AGM vs 6v flooded leaves important factors undecided. You need to have similar amp-hour capacity to make comparison meaningful.


Assuming the two 6v's are GC2 golf car batteries, we can guess the AH is either 210 or 225 (the two more-or-less standard sizes), but what size and AH 12v are you comparing to? And how does that AH capacity compare to your typical off-grid needs? If your battery bank is undersized vs typical demand, the batteries will be frequently deep-discharged and that shortens their useful life.


A pair of Group 27 AGM 12v will probably be about the same capacity as a pair of 6v 210 AH batteries, but it takes a Group 31 size to equal the larger 230 AH size 6v.

[twinboat]

If AGM is important, get 6 volt AGM.

You'll still probably save money, gain capacity and service life.

[Bob_C]

Agm's require a different charge rate from a lead acid battery

[Ray,IN]

You should not mount flooded LA batteries inside living quarters. You don't want a "boom in the night" experience. This picture shows them inside the van body.

[Gary RVRoamer]

Agm's require a different charge rate from a lead acid battery

IMO that is somewhat of an overstatement. First of all, AGMs are a lead acid battery, so the basic electrochemical action is the same. Second, the charge rate differences are small and only a little off from the optimal value values (usually within 0.1v in all stages). So yes, AGMs like to have a charger optimized for their performance, but the difference isn't enough to prohibit their use.