I was Recently contacted and asked about battery and alternator wiring upgrades for the jeep cherokee. I have recently done it so I wanted to give a run down of how to do it and what you need. Its a real simple upgrade, and if you ever decide to go to a higher than stock amperage alternator, you will already have the wiring to support it.
1st you will need 5 or so feet of red 2-4Ga wiring 7 to be safe, and 5 or so 2-4gad black for ground wiring. Also you will need some eyelet style terminal connectors, and a Pair of new "marine" terminals. The wiring id hit a local Stereo installation shop for. they will sell the fat wire by the foot. The marine Battery Terminals and round eyelet connectors can be found at any local auto parts store for cheap.
Replace the Ground wire front the battery to to the core support, Keep all the ground as short as you can, they will lose conductivity the longer they are. Not power lines, just the grounds.
Replace the longer ground from the battery to the Engine Block. I have a 3rd ground for the winch. you may or may not have to run that as well.
Once that is done you can tackle the power side. Make sure to disconnect the battery before any of the wires. you might get a spark or Two ;) Start with the one running from the battery to the front of the under hood fuse box.
Then from the same mounting point run another fat wire down to the alternator (single post side)
One more wire and your done! The Starter. Run a new fatty from the battery down to the main post on the starter. If You have a winch, you will have to run that power wire too. but all and all thats it! hook the battery back up and crank the key.