Battery charging director for dual batteries

[prndl]

Years ago I installed a simple device I found somewhere that would use the existing trailer battery charger and spit the charging circuit to two separate batteries.

I have two 12V batteries that I use via a 1, 2, Off, Both switch. With both batteries off line I want to keep them charged from the existing trailer converter.
I wonder if anyone else knows of the device that will take in the charge line from the converter and send the charging circuit to the battery that is low.

I found dual battery chargers. don't want to go that route.
Found battery isolators, not what I am looking for.

The device I had would sense the battery that was low and charge it and I think after charging that it kept a float charge going to them both until again, one or the other needed a normal charge.

Any ideas?

[rohrmann]

Why not just switch that device to Both Batteries and just use the built-in converter/charger, which will do an excellent job maintaining your batteries without adding another device.

[Foldbak]

The device you describe is a smart charger. Most modern converters are smart. They adjust the state of charge based upon the need to prevent overcharging. I don't think your 2011 has a smart charger. Victron several chargers. You might look there.
https://www.amazon.com/Victron-Energ...300619676&th=1

[prndl]

Thanks guys for the responses.

I want to use the on board charger, no problem there.

I have two independent battery banks of 12V each that I use one at a time. Never use the All position on my switch.

The device I had before would send the charge from the on board converter to one battery bank or the other and never to both at the same time.

It was similar to a motorhome charging system that would send charging current to the house batteries OR the starting battery to keep both systems charged.

I just want the device that directs the charge and not a new charger.

[AZ Traveler]

Brian,

What do you see as the downside of using the all position?

[prndl]

Batteries are not of the same age or aH rating.

[Daryles]

Maybe a BIM?
Why not just wire the batteries in parallel?

[rohrmann]

Can you wire in another converter, like a floor mounted unit and use the existing one for one battery bank and the new converter for the other bank?

[DDPhillips52]

What you are looking for is this.
Magnum Energy Smart Battery Combiner.
Had one in my Open Range 5th Wheel. Works great.