The Hypertech Battery Combiner 200 is a precision voltage-sensing relay (13.0 volts) which connects two batteries together when either is receiving a charge. When the charging ceases, it disconnects so that each battery operates independently and prevents accidental discharge of the starting battery.
Supplemental battery banks can be added by using an additional Combiner for each bank. It eliminates manual switching every time you start the engine to parallel batteries for charging. Never again forget to switch it back. No diodes so no voltage drop, and batteries get a full charge.
Smaller charging sources may be able to use the Hypertech Battery Combiner 100.
The Hypertech Battery Combiner 200 should not be paired with lithium-type batteries. For lithium battery installs, consider the Hypertech Battery Combiner 200 for Lithium Batteries.