Chat with us, powered by LiveChat How to Replace Your Jeep Wrangler Battery and Upgrade Terminals | Quadratec Skip to main content
How-tos

by Scott Ammerman
Torque Senior Correspondent


So my battery decided to give up on life recently, which just happened to be the first cold morning of the fall. No worries. I ordered an Optima Red Top battery from Quadratec to upgrade, but while I was replacing the battery, I noticed that the factory terminals weren’t very thick and had a decent amount of fuzzy corrosion. Since I’m planning on adding a winch and other electrical accessories shortly, it seemed like a good idea to upgrade the weak OEM JK terminals with something more reliable.

The Quadratec Extreme Duty Battery Terminal Kit includes everything you need to replace those thin metal terminals with ones made of solid lead, but also adds solid brass accessory rails. The best part is, they’re adjustable for angle - so even with the shorter spacing between the terminals on the Optima battery, they can still be adapted to work.

What you will need:

  • 10mm wrench for removing factory terminals
  • 12mm wrench for removing nut holding the negative cable
  • A wire brush to clean the cable end terminals
  • 10mm socket with long extension if you’re replacing your battery
  • A battery terminal cleaning tool if you’re reusing your battery
  • ½” wrench (13mm will work) for tightening nuts to close around battery posts, negative terminal to brass rail
  • 9/16” wrench (14mm will work) for tightening positive terminal to brass rail
  • ⅜” wrench or socket to tighten down factory cable ends on new terminals
  • A flat head screwdriver to spread new terminal clamps open

I started by cutting the cable tie around the battery cables, as I needed a little more adjustment than I could get with it there. A standard wide post battery might not need that extra movement, so you can leave it in place if you wish, or cut and replace if your garage is full of extra cable ties like mine.

Note: When disconnecting the battery, always start with the negative side first. Also keep in mind that, if you are dealing with an old and possibly leaky battery, the acid seeping out can do nasty stuff to your skin and clothing. The longer it stays on you, the worse it can be, so wash your hands with soap and water soon after touching anything that could have acid on it, including your old terminals. Or, you know... Wear gloves.

Remove the 12mm nut holding the negative cable end, and then move these cables out of your way as much as you can to avoid arcing across the positive side with those shiny metal tools you’re going to use. Then, remove the 10mm nut from the positive side terminal holding those cables down, and push them out of the way. Loosen both 10mm nuts holding the factory terminals onto the battery, and remove the two terminals as you won’t need them any longer.

If you’re replacing your Jeep battery with a new one, take the 10mm bolt out of the hold down clamp in the lower front and remove it entirely. Drop the new battery in place, center it, and tighten the clamp back down.

If you’re reusing your battery, clean all corrosion off the tops of the posts with a terminal cleaning tool.

In either case, clean the cable end terminals with a wire brush to remove any nasty stuff stuck to them, and then install the two battery terminal protectors included in the kit on the battery posts. Make sure the red one is on your positive post, and the other one (either green or black, depending on kit contents) is on the negative post.

Spread the clamps on the Heavy Duty Battery Terminals and open slightly with a flat-head screwdriver. The terminals look very similar, but the positive side has a larger bolt where the terminal connects to the brass rail. For the Optima, I had to reverse both brass rails to spread the cables out enough. With a standard wide post battery, you want them pointed inwards and to the front as indicated in the included instruction sheet.

Fully seat the terminals in the correct orientation for your battery, and tighten the ½-inch nut on each to close the clamp. Remember, these are electrical connections, so get them nice and snug.

Next, move on to tighten down the two nuts that hold the brass down onto the terminals. The positive side is 9/16-inch, but you can use a 14mm. The negative side is ½-inch, or 13mm. They’re actually standard fasteners, but these metric sizes are close enough to to work.

The factory cable ends go under the next ⅜-inch bolt down the rail. A 10mm is close, but will not be small enough to fully tighten these connections.

Note: Pay attention to the direction the cables point to ensure they aren’t able to rub against each other (or anything else). These heavy gauge wires have an ample amount of insulation, but vibration from driving can cause abrasion and an increased risk of fire.

Now that these are fully installed, you have two additional options to add electrical accessories:

Wires for medium to low amperage accessories can be added to the end of the rail

Higher current items (like winches) can be added to the larger studs that connect the terminal to the brass rails.

Note: The ⅜-inch bolts holding the factory cables down should not be used for anything else.


Related Articles:

Best Jeep Products for Spring 2022

Choosing The Best Jeep Tires

How To Increase Your Jeep's Fuel Economy

Top Jeep Articles

Red Wrangler on a white background
  • May 27, 2026
  • 5 min read
Jeep Bumper Questions Answered: Everything Wrangler Owners Need to Know Before Upgrading
Not all aftermarket Jeep bumpers are created equal. So if you are in the market for a new one, here are some common-sense answers.
READ MORE
Green and black Jeep against a rocky background
  • May 26, 2026
  • 4 min read
Jeep’s Future Product Blitz Signals a Return to Bold, Enthusiast-Driven Performance
New reports on Stellantis’ long-term roadmap suggest Jeep is preparing a dramatic expansion of its off-road and performance lineup, including a revived Scrambler pickup, the return of SRT models, and a gas-powered version of the upcoming Recon.
READ MORE
  • May 25, 2026
  • 5 min read
Jeep Death Wobble Q&A: Causes, Symptoms, Fixes and How to Prevent It
Learn what death wobble is, why it happens on solid-axle Wrangler and Gladiator models, and the exact components to inspect for a safe, lasting repair.
READ MORE
  • May 19, 2026
  • 4 min read
Memorial Day Jeep Adventures Start with Preparation, Responsibility, and the Right Gear
From trail recovery gear and camping essentials to responsible off-road practices, here’s how Jeep owners can prepare for a safe, adventure-filled Memorial Day weekend while helping protect public lands for future generations.
READ MORE
White Jeep Wrangler with a colorful background
  • May 18, 2026
  • 3 min read
Could Jeep’s Next Electrified Off-Roaders Really Come From China?
A new Stellantis partnership with Chinese automaker Dongfeng could shape the future of Jeep EV production, raising questions about global manufacturing, electrification, and what it means for the brand’s American identity.
READ MORE
  • May 13, 2026
  • 3 min read
Jeep Debuts Canada-Exclusive Wrangler Rocky Mountain 392 With HEMI V-8 Power
The latest Twelve 4 Twelve special edition gives Canadian Jeep fans a Wrangler 392 packed with V-8 performance, exclusive styling details, and open-air capability.
READ MORE
  • May 12, 2026
  • 3 min read
Jeep Unveils Wrangler America250 Edition With Patriotic Styling and Captain America Collaboration
Jeep’s seventh Twelve 4 Twelve special edition celebrates America’s 250th anniversary with red, white and blue styling, Willys capability, and an exclusive Marvel collaboration.
READ MORE