Do I Need an Isolator for Lithium Batteries?

Question:

In your seminar on battery isolators, you mention an isolator for lithium batteries to the start battery.  I think it will protect the alternator from the lithium cutting off but what about a high amp charge? That can cook the alternator?  Any protection with an Isolator?  - Gianfranco

Answer:

When we charge two different battery bank chemistries, there needs to be separation but we want them to charge from one source.  The best option is for a DC-DC charger, this allows the engine battery to connect directly to the alternator output and take the output in the event of a battery management system (BMS) shutdown. Also the DC-DC will regulate the voltage to the lithium and high-output can be controlled by the size of DC-DC you select.