Dual Battery Junction Box

WARNING: This page is about a different car, the 2015 Jaguar XF, 2014 Jaguar XF, and 2013 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

The DBJB is located adjacent to the primary battery. The DBJB houses two contactors which are controlled by the DBM and the GWM for switching power supplies during ECO stop/starts and also for charging the secondary battery.

FET's (Field Effect Transistor's) are also located in the DBJB. The FET's are connected in parallel with contactor 1 and allow the primary battery power to flow to the sensitive loads during the contactor switching process to ensure there is no interruption in power supply to the sensitive loads. The FET's also act as a secondary path to allow power to be supplied to the sensitive loads should a fault occur and the contactor 1 becomes stuck open. The FET's will allow a current of up to 200A to flow through them.

The DBJB receives a battery supply direct from the primary battery to contactor 1 and a battery supply from the secondary battery to contactor 2. Two connections from the DBM are used for contactor coil control. A third connection from the DBM applies a stabilized voltage to the secondary battery for charging when requested by the GWM.