Balmar Digital Duo Charge 12/24V Battery Combiner

Description

The Balmar Digital Duo Charge DDC-12/24 provides automatic charging for a starting battery from a house-bank charging system without requiring a traditional diode isolator, manual battery switch, or continuously paralleled battery banks. It is designed as a hands-off solution for boats that need to keep a start battery charged while maintaining electrical separation between the start and house banks when no charging source is available.

During charging, the Digital Duo Charge monitors voltage at the house battery. When house-bank voltage rises above the configured threshold, typically about 13.2V on a 12V system or 26.4V on a 24V system, the unit automatically engages and sends up to 30 amps of charge current to the starting battery. When charging stops and voltage falls, the batteries are separated again so house loads cannot accidentally discharge the starting battery.

The DDC is a solid-state battery combiner rather than a simple mechanical relay. It controls voltage and current between the house and start banks and can be used with Balmar Max Charge or ARS regulators, but it can also operate without a Balmar regulator. Both 12V and 24V applications are supported.

House and starting batteries do not have to use the same battery technology. The unit supports four start-battery charging programs: standard flooded, deep-cycle flooded, AGM, and gel cell. Optional start-battery temperature sensing can be added with the MC-TS-B sensor cable.

For systems that require more starting-battery charge current than the built-in 30A capability, the DDC can control an optional solenoid to increase output. For cruising boats with separated house and starting banks, the Digital Duo Charge provides automatic charging while preserving the reserve capacity of the engine-start battery. Find more in our battery isolators & charging relays.