WBI = WhisperPower Battery Isolator.
It is used when charging several batteries of different circuits with one charger (12, 24 or 48V), the voltage drop is minimal, so WBI does not waste energy. In standard diode dividers, the voltage drop is significant (0.6V), so the batteries are not fully charged. With the WP distribution diode, when the charging current of the batteries has decreased below 10A/battery (the battery is approaching full charge), the voltage drop is practically 0 = the battery is fully charged.