Originally Posted by WesK
Just to clear things up, the term "battery combiner" and automatic charging relay" are descriptions of the same device, just from different manufacturers.
This is not something designed to connect two batteries together to start the engine, it is a device to connect them together for charging.
If you want a way to connect both batteries together for emergency engine starting, a standard battery on/off switch wired between the two would do. Or a jumper cable.
This Blue Sea ML-ACR Automatic Charging Relay
is definitely designed to do Just that. The 30 sec. Cranking Rating is 1450A DC.
"The ML-ACR (Automatic Charging Relay) and ML-RBS (Remote Battery Switch), when paired, offer complete battery management of large battery banks with the push of a button. In addition to automatically sharing the charge from an engine’s alternator between the start and auxiliary battery, the ML-ACR control switch provides momentary battery combining to assist with starting in the event of a low engine battery
. Multiple remote battery switches can be easily connected to the ML-ACR with the optional Paralleling Link Bus for a complete remote battery management Subsystem."