Originally Posted by
MLA
Mike,
In theory, yes, if the house bank is heavily depleted, the main cranking would try to equalize with the low house bank. But, the low voltage setting on the ACR will quickly be reached and the ACR will again open and isolate the banks. This bouncing/cycling will continue until the house bank reaches a level of charge to where the ACR stays combined.
So in actuality, the ACR will not combine a full battery and dead battery and stay combined, thus allowing the full battery to equalize with the dead. When the house bank is heavily depleted, rotating the switch to combine will circumvent the ACR, allowing the house bank to receive and steady charge from the alternator and getting back up as fast as possible. As long as the engine is running, equalizing will not be an issue, so if you stop again, switch off of COMBINE.