The SBC-BS3003 battery separator is designed for use in multi-battery applications. It works as a solenoid priority system to protect the charging system from excessive load while allowing auxiliary batteries to charge. The SBC-BS3003 activates only when the primary battery system exceeds 13.2 volts allowing for the secondary batteries to charge properly. It also uses this technology to protect the charging system from excessive drains on either battery bank. The SBC-BS3003 also compares the voltages from both battery banks. If the primary battery bank has a low charge, the SBC-BS3003 engages the auxiliary system to assist in engine start-up.