How to replace a motorcycle battery

By Allstate

Last updated: January 1

One of the essential maintenance activities for your motorcycle is performing routine upkeep and replacing parts when necessary. This includes your motorcycle battery. According to Motor Gear Expert, a sealed Absorbed Glass Mat (AGM) battery usually lasts from about three to five years. A conventional acid-filled battery has a lifetime of two to five years.

If you suspect it's time to replace your motorcycle battery, the following are tips on how to do it right.

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When should you replace your motorcycle battery?

There are a few reasons why you may need to replace your motorcycle battery, says Motor Gear Expert:

  1. Your motorcycle's generator or alternator should charge the battery while you are running the bike, but if the battery isn't holding a charge properly, your bike may not start the next time you try it.
  2. The engine cranks over slowly or does not crank at all when you try to start it.
  3. Your battery is between two and five years old, and you want to replace it as a preventive measure so you don't run the risk of being stranded somewhere.

When you first notice that your motorcycle battery isn't holding a charge, you may wonder if it is flat and can be recharged, or if it needs to be completely replaced, says They explain that this is an important distinction because of the high cost of new motorcycle batteries. You can check the battery yourself if you have a voltmeter, or you can bring it the nearest motorcycle shop and have them charge the battery, then run a load test. If your battery fails the load test, you'll need to replace it.

How to replace a motorcycle battery

Your first step is to take out the old battery. Your service manual will be able to tell you exactly where your battery is located, but notes a few common places: under the seat, under the fuel tank or under the side covers.

Once you find it, sliding out the battery will allow you access to the battery terminals. It's important to disconnect the negative cable first when disconnecting the battery cables, advises Revzilla. After the circuit is broken, you may remove the positive cable. Then carefully remove the old battery and install the new battery.

What do you need to know about getting a new battery?

When you get a new motorcycle battery, it's important to ensure you're charging it correctly the first time, according to Motor Gear Expert. They further recommend that you read the safety information that comes with the battery. If your new battery needs to be filled with acid, be sure you fill it before you put it in the bike so you don't inadvertently spill acid on your bike. Some batteries don't come with acid; in that case, it's best to have the local motorcycle shop fill it for you.

When filling the battery yourself, Motor Gear Expert advises you to use caution and do it outdoors or in a well-ventilated area. Keep baking soda and water close by just in case you need to neutralize any stray acid.

Check the instructions that come with your battery and follow these steps to charge your battery for the first time, says Motor Gear Expert:

  1. Don't use an automotive battery charger. A motorcycle needs a lower amperage charger to avoid damaging the battery.
  2. Figure out the amperage to charge your new battery by dividing the Ah rating by 10.
  3. Use crocodile clamps to hook up the battery tender.
  4. Charge until the indicator tells you the battery is completely charged.
  5. Remove the charger immediately to avoid overcharging the battery.

Keep safety in mind recommends that you wear the proper safety gear for this project: gloves and safety glasses are a must. You should also make sure your ignition key is in the "off" position for this entire procedure. If you go through the steps of replacing your battery and you feel unsafe, you should seek the help of a professional mechanic.

How can you extend the life of your battery?

If you want to extend the life of your motorcycle battery, try these tips from YUASA Batteries:

  • Keep the battery charged.
  • Stick to a maintenance schedule where you check for corrosion and electrolyte levels.
  • Regulate the temperature to keep vapor loss at a minimum.
  • Use the proper battery for your motorcycle.