Although we could have simply installed the Optima battery using the stock power cables, the larger-diameter cables will permit the maximum load of electrical current from the battery to the starter and alternator. The larger the cable, the greater amount of electrical current it can safely carry. Jeepers and Creepers offers heavy-duty power-cable kits for TJ, ZJ, WJ, and XJ Jeeps. Optima batteries are available for any vehicle.
Our existing battery had been in place for some time, and the cables were more than 10 years old. We had begun to experience difficult starts after the vehicle would sit for a week or so, and with just one accessory connected at the time we didn't have much room for more. The buildup of grease on the cables was also impairing performance. | 
We removed the existing battery and used a vacuum cleaner to clear the tray of debris that had collected. The Optima YellowTop battery is a bit taller than some batteries, but we were confident that it would fit the stock tray without issue. | 
In removing the positive power cable, it was necessary to cut it free from a section of wire loom. With little space to work, this proved to be the longest step of the installation. |
The starter end of the positive power cable is shown here. We'll use a razorblade to cut the wires apart since we'll retain the green ignition wire. | 
Shown next to the original cables, the heavy-duty cables from Jeepers and Creepers are noticeably larger, which will result in greater electrical flow. The military-spec battery clamps will ensure a better connection with the battery that won't loosen up as easily as the factory cables. | 
With the new battery clamps and ground wires set aside, we routed the new power cables to the proper connections and used zip ties and wire loom to secure them from abrasion. |
The Optima battery was then set in the battery tray and secured using the factory battery hold-down. | 
With the battery secured, the power cables and ground wires were attached to the military-spec clamps. | |