AGM and Wet Cell in parallel

beemerphile1 wrote:
I wouldn't suggest the combo if buying new, but since you already have both batteries there really is no downside.

X-3

Buy a battery isolator switch and use them separately.

I wouldn't suggest the combo if buying new, but since you already have both batteries there really is no downside.

Thanks to all. The AGM will be installed inside a truck camper where it is hard to maintain a wet cell battery. The conventional deep cycle will be outside in front of the wheel well in the truck bed. I plan to use a quick disconnect to facilitate unloading/loading the truck camper. The AGM alone will be used when the camper is unloaded and hooked to shore power. The combination will be connected when boondocking with the camper on the truck.

The puriests say "NEVER MIX"

I do not recommend it, but.. I've done it... the differences are very minor very very minor in charging voltages and such.. I do not think you will have any problem paralleling them.

Around twenty years ago I tried to wilderness camp with mixed batteries. I promised myself I would disconnect them faithfully when they were not being charged or actively discharged. Four months later, eight replacement batteries. I hate it when my cheapness makes me go stupid.

so get a cheap A/B switch at harbor freight???
bumpy

I doubt the battery that came with your Rv is indeed a true Deep cycle but that is not really relevant to your question.

YOu can discharge them together, but it is not ideal. The AGM likely has a higher resting voltage and less resistance and will be taking up more of the charging current and giving more of its available capacity when discharging than the flooded.

I have one of each but it is rare that I Discharge them together, and I will not leave them( intentionally) to rest paralleled together.

I do allow them to share charging sources occasionally but each battery prefers slightly different settings which I try to meet.

It will work. Is it ideal, no. Will you get the full additional capacity of the AGM? Unlikely.

I have some links for that but I'm using the phone and don't have access to them. be later.

It will work fine while in use. Separate the batteries if stored without a float.

And yes I have paralleled Optima AGM and Interstate flooded.