Anyone have suggestions or schematics for building/converting a 12 volt car battery charger to one that has more control for float and current limit? I have an old schematic modifed from a large industrial 120 volt circuit. It works fine but there ought to better modern units.

 

How much current required?

 

Gee the ones you can buy at Walmart or Sam's Club for $40.00 look pretty impressive to me. Don't think I could build one for several times that price. They handle 10-15 Amps of charging current.

 

My chargers are 20 and 25 amp. Got lots of old parts and my old home built unit uses SCR and old common parts but I thought there might be something that use integrated circuits etc and wouldn't cost much. I don't have the ability to design such a circuit. I haven't looked at what Wallmart has for sale.