Thanks - but that's not what equalizers and convertors are for. Those are for OUTPUTS. I've used equalizers before (military applications). I'm asking about the INPUT side - the 12vdc charging side. AFAIK, there is nothing other than battery isolators.

I am eager to hear otherwise.

That's a company with some great products, BTW - thanks for the link.

Tom

EDIT: I found some neat DC input 2 and 3 stage chargers. Although the majority are NOT for 12 vdc batteries, there are a few models. The maximum charging amperages are fairly modest and are in any event linked to the ratio between input and output voltages. It would take hours and hours to recharge a deep cycle battery discharged to 50% level (common) and worse for 80% discharge level (feasible with true deep cycle batteries). A battery isolator would still have to be in the circuit ahead of it, I think - maybe not. It looks like these are pretty specialized and I would be surprised to find one in an RV, although I suppose you could get one if you really wanted. Maybe other companies make these in larger capacities...?

I'm going to stick with battery isolators and not worry about getting maximum life from a semi-deep cycle battery. I've got 10 years on one that's holding up fine and three years on another, ditto. END EDIT