Bob replied:

Thomas, you might consider fitting a Optima battery. Im'm sure it would fit. I have installed two in my Toyota, work well over the last two years with extensive off road work including GBH and the Canning and extreme rough work in the Victorian Alps. They take a charge very quickly. The yellow top is both cranking and deep cycle.
Expensive but worth it after having other battery's fail on two occassions. Bob.

Barry replied:

Thomas, i agree with Bob on the fitting a Optima battery. Im'm sure it would fit. I have one in my Disco series 1

Mark Wilson replied:

Thomas, I have done the same thing as the others but have opted for an Orbital battery which is made by Exide. The battery works fine, is much smaller that its lead acid counterparts and is much smaller. I suggest you search the Internet looking for Absorbed Glass Mat batteries or go to the Exide or Optima sites. Beware they're more expensive that the lead acid plate batteries but the "spiral cell" technology allows the manufacturer to use purer forms of lead and therefore get higher performance as a result of the reaction between the lead and the electrolyte. Hoipe this helps. regards Mark

Nigel replied:

Why do people suggest a 55 Ah battery when you want a 100 Ah battery? Ring Alco Battery sales in Brisbane, they may know who stocks them over your way, or you can get them freighted like I did. Ph them on 07 3299 2600.