Automatic Charging Relays (ACRs) are part of a family of devices that manage the charging of two battery banks with a single charge source. Battery combiners, isolators and separators can perform similar functions, but ACRs work without the voltage drop, heat and undercharging associated with diodebased products. When the ACR senses a charge present on either battery bank, it will combine the batteries. When there is no charge present, the ACR isolates the batteries and prevents the starting battery from being discharged by coach loads. Senses voltage on either battery bank, and integrated LED indicates ACR status. Suitable for alternators up to 120A. For 12 or 24V DC systems.