Know you‘ve got the power to work & play anywhere with the Auxiliary Battery Kit. Adds a second battery to the Defender to enhance its electrical system for Heavy Duty use and stress-free power needs. Allows you to add a second 30Ah battery for that dual battery setup that will give you the extra juice you'll need to power auxiliary electrical components like a sound system or winch. Equipped with an integrated smart battery isolator that will prevent your auxiliary electrical components from draining your starting battery. Kit includes an additional battery junction block, all necessary wiring, and the battery holder. Additional battery sold separately (515176151).