How to Change a Car Battery
The basic steps to swap out a dead battery for a new one
- Cars 101
- Guides & Gear
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The car battery is the thing that makes it all happen in terms of getting a vehicle’s engine running. If you’ve ever sat in a parking lot, listening to the car crank and crank to no avail, you know what happens when the battery is out of the equation.
Thankfully, dealing with a dead battery isn’t a difficult issue to address. If you can’t recharge the battery you have, the next best (and probably only) thing you can do is swap it out for a new one. The process is simple as long as you take some cautious steps, so here’s how to replace a car battery in just a few easy steps. ou need to know.
Estimated Time Needed - 30 minutes
Skill Level -Beginner
Vehicle System - Electrical
It’s important to remember that you’re dealing with electricity when working on a car battery. As a result, there are a few important safety steps to take.
- While not necessary to remove the battery, rubber gloves can add a small degree of safety when dealing with electricity.
- Never connect any cables that shouldn’t be connected. That means avoid swapping the wrong battery cables and battery posts or putting the cables anywhere they’re not supposed to go.
- Be careful when removing the old battery. If it’s damaged and/or leaking, you may want to let a professional do the work instead.
Everything You’ll Need
- Replacement battery
You’ll also need a flat surface, such as a garage floor, driveway, parking garage, or street parking, though check your local laws to make sure you’re not violating any codes when using the street because we ain’t getting your car out of the impound yard.
Arranging Your Workspace
Organizing your workspace and tools so that everything is easily reachable will save you hours hunting for the mythical 10mm socket, wasting time getting up and grabbing parts from your worktable, or waiting for your handy-dandy child helper to hand you the hammer or blowtorch—Ed. Note please don’t have your kid hand you a blowtorch.
Here are our suggestions for making your life easier.
- Open the car's hood.
- Put the replacement battery somewhere close, along with your wrenches and sockets.
- Mark a spot where the old battery will go.
How to Replace a Battery
Let's do this!
Removing the old battery and replacing it with a new one is a fairly straightforward process. It doesn’t require much in terms of special tools, and the process can go quickly if you’ve taken the basic preparation steps ahead of time.
Removing the Old Battery
- Remove the negative cable from the negative terminal—the one with the minus sign. Depending on the design of the battery, you may need a wrench to loosen the cable-free.
- Remove the positive cable from the positive terminal—the one with the plus sign. If you are using a tool like a wrench, make sure the metal doesn’t contact the terminal as it will spark.
- Loosen the battery hold-down, connectors, and/or fasteners that secure the battery in place.
- Lift the battery out. The weight of the battery may be over 50 pounds, so get some help if necessary. Put the battery to the side in a safe spot.
Add the New Battery
- Clean the clamps. Before you actually add the battery, try to remove any corrosion, dirt, or debris from the clamps. You can also clean the battery terminals from any build-up issues. A skinny wire brush and some water or baking soda are usually all you need.
- Put the new battery into the holder.
- Secure the battery.
- Reconnect the positive terminal.
- Reconnect the negative terminal.
- Test the car. You can try to crank up the engine or just turn on the electronics. If everything powers up, the battery is properly installed and you’re ready to get going.
Tips From a Pro
We've done hundreds of battery swaps in our time. Here are our go-to top-tips for all you budding mechanics.
- Inspect the battery every now and then to assess its condition.
- Most car batteries need to be recharged or replaced after around five years of use.
- Make sure you get the right battery for your vehicle. Consult the owner’s manual for detailed information.
- Keep the batteries in an upright position to avoid leaking any electrolyte solution.
Is there any danger to changing a car battery?
There can be some inherent risk to changing a car battery. Cracks and corrosion from the old battery can cause some dangerous battery acid leakage. The battery can also still produce a charge, even when the car is off, so you have to keep in mind that you’re working with electricity.
How do I know which side to remove or connect first?
It’s always the opposite side when removing vs. adding cables. The negative side always gets removed first. The positive always gets connected first.
Do I have to replace the old battery?
You can often recharge an old car battery before it needs to be replaced completely. To do so, you’ll need a charger, and the battery needs to be able to hold a charge.
Will changing the battery affect the on-board computers?
It shouldn’t, but some computers may experience a reset or memory loss. Damage can occur if disconnecting the battery produces a high-voltage energy spike.
Since you may not have access to the right tools, or have a friend you can bum a wrench off of, we also compiled a list of our best hacks to make your life easier and drain your pocket less.
- If your battery is dead, you don't have the replacement one yet, and can't get to one, remove the battery's top carefully and drop 2 tablets of aspirin into the battery as the active ingredient will provide enough of a chemical response as to provide one last spark.
- Cold weather is the enemy of batteries. To protect against it, before winter comes, remove the battery terminals, clean, and then replace them after you've smeared them with petroleum jelly which will protect against corrosion and help maintain spark during cold weather.