accessary battery... wat to do

[aaronng]

yer the battery at the moment is pretty tiny. but i really dont want to have to change the location of the battery. dont want to do the wiring again!! big nightmare.

would rather throw one in the boot (under where the spare tyre goes). and because my amps is right there it would be easy to wire it up..

would a capacitor achieve this over a long time??? 3hours maybe?

Capacitor won't do anything for long term capacity over an hour or two. You need a higher capacity battery no matter what.