Victron Orion-Tr 24/12-20A Isolated DC-DC Converter - ORI241224110 175W Victron DIN35 Adapter Large:

Victron DIN35 Adapter Large:

Argofet Isolators allow simultaneous charging of two or more batteries from one alternator (or a single output battery charger)

The MultiPlus will then take account of other AC loads and use whatever is extra for charging

It can only deal with current in one direction

FET Isolators have virtually no voltage loss

Victron Orion-Tr 24/12-20A Isolated DC-DC Converter - ORI241224110 175W Victron DIN35 Adapter Large:Victron Orion Tr DC DC Converters Isolated: A DC DC converter converts one DC voltage to another. The operating voltage of different electronic devices can vary over a wide range, making it necessary to provide a voltage for each device. The Orion IP43 DC DC Converter is short circuit proof and can be paralleled to increase output current. An unlimited number of units can be connected in parallel.