Need a new battery for your Jeep? You can fit a much larger battery in the stock tray. I've done this to several TJs and YJs now, so I figured I'd share.
YJs typcially call for a group 58 battery.
TJs typically call for a group 34 battery.
A group 65 battery will fit in the factory tray, and the factory hold down will work with a slight modification.
Your factory hold down has two little tabs under it to locate the battery.
You can just tighten the hold down with one tab ontop of the battery, and it will hold fine. Just make sure not to tighten it down too much.
Your other option is cut the back tab off, or just beat it down with a hammer, so it is flat and the hold down will lay more flat.
Typically all the different group sizes of batteries are very close in price, switching to a group 65 battery gives you a much larger reserve capacity, and typically a lot more cranking amps.