An Automatic Combiner Relay (ACR) is often used in vehicle applications such as RVs, Work Trucks, Marine vessels, etc. to allow charging separate Chassis and House batteries from common charge sources such as an engine alternator, inverter/charger, solar. In a typical vehicle the chassis battery is reserved for engine starting, while the house battery is used for “hotel” (or house loads) or work-related loads. Normally, when the engine is running, the chassis battery is charging, but when the vehicle is stationary and connected to the power grid, the house battery is charging. Our intelligent 12V ACR allows customers to take advantage of all situations to keep both batteries charged, while keeping them separate when charging is not available or not desirable.

Lithium batteries have an advantage of absorbing as much charge current as possible during the bulk charge stage, which could overheat and potentially damage stock engine alternators, so our intelligent 12V ACR reduces the duty cycle and allows cooling periods. At the same time, a lithium battery requires charge termination when fully charged, so our 12V ACR keeps it disconnected after the charge cycle is completed.

In addition, the Lithionics Battery® 12V ACR provides solutions for less common use cases where 2nd alternator is installed to charge the house battery, but its internal regulator is not designed for fine charge control of lithium batteries, as well as cases where a 3rd party battery disconnect (ex. Mastervolt Charge Mate Pro 40) is used to current-limit the alternator, but needs an intelligent additional control to terminate the charge of a lithium battery.

View the application guide here: Lithionics Battery ACR Applications Overview