Hmm.. well it finished charging. Will try to put it back later today.
I was hoping to put in a yellow top as you suggested (although I still think $360 for a battery is quite steep), but the battery cables aren't long enough to accomodate a bigger battery, and I'd have to change ther terminal rings to bigger ones as well.
Ground cable connection, which I could possibly replace to accomodate a bigger battery.
+ve terminal connection
The positive terminal is wired into this power supply thing. Try as I might, I cannot remove it. This is a bummer as it means I am restricted to buying batteries only as high as my old tiny battery, as there is no slack in the wire when the battery is there.
Apart from the +ve and -ve terminals, there is a drain tube of some sort going into the battery
which slots into this hole in the battery
I have no idea what this is... is this for leaking acid or something? I would have thought the Pitwork battery that Nissan put in the stock GTR would have been a sealed type, and wouldn't need this.