Installing a 3rd Battery

For any serious touring, power consumption is always in the back of your mind, this is why we decided to add a 3rd battery for our South Island expedition.

The 74 Series runs a full 24V starting and electrical system, so for us to be able to charge a AA Champion 12V 71 A/h deep cycle gel battery we had to add a few additions to the conventional dual battery set up.

The first thing you will notice is the giant red box bolted to the top of the battery box. This red box is a 24-12V DC-DC smart battery charger made by PowerTech. It steps down the 24V input to a 12V charge from the start battery’s whilst regulating the charging cycle to prolong the lifespan of the 3rd battery.

Mounted to the side of the battery box is a Aopec 24V smart battery isolator that automatically cuts in at 26.6V to allow the battery to charge and cuts out at 25.6V isolating the start batteries. This prevents us from draining the start batteries and not being able to make it home from the campsite after using our Waeco fridge, air compressor and 300W inverter.