BR100 is a solenoid type of high current relay that is typically used to isolate either house or engine batteries from the electrical system they are connected to. This is done to prevent complete battery discharge in long storage periods. It can also be used to isolate batteries in banks to aid in charging or keeping reserve power. The electrical ratings are 12V DC, 100 Amperes continuous, 300 Amperes for surges up to 30 seconds. Mounting brackets must be connected to 12V negative. The BR100 has two 10-Ampere DC fused “accessory” circuits; one on the battery side and one on the 12V system side.