colm_mcm wrote:The biggest one that will fit
I put a huge one for a Lexus into my first one.
The standard one is a joke.
A joke maybe but the small battery that it comes with works plenty fine - even through all of the weather we had over the past 2 years. I've replaced my 'Micra' battery once in the past 12 years of driving my FTO.
I've even had that tiny battery run an uprated stereo, amp, speakers and 2 x 10" subwoofers without an issue.
Buy whatever suits you best from a cost perspective.