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When to Replace Your Lawn Mower Battery According to Landscaping Pros: Plus Tips for Extending Battery Life

Plus learn when it's better to just replace the mower!

Few things can be more annoying than finding your lawn mower isn’t running at full power — or won’t start up at all! The problem may very well be with your mower’s battery. A faulty battery can keep your machine from working properly to cut the grass. We asked lawn pros how to know if you need a new lawn mower battery, what to look for when buying one and how to help your battery last.

The types of lawn mower batteries

Changing a lawn mower battery

In general lawn mower batteries function they same way as any other battery and provide power to the machine in order for it to run,” says Matt Davies, managing director at Garden Lawncare Guy.

You will usually find three main types of batteries in lawn mowers. First, larger machines and ride-on mowers usually have a battery that has two terminals that can be connected up (similar to what’s found in a car).

“For smaller push type mowers you have more portable batteries that slide in an out of the machine — in most cases these are proprietary batteries but some units offer batteries than can also be used on other power tools like drills, hedge shears and other tools,” explains Davies. Lastly, some mowers have integrated batteries, though this is less common.

That’s not the only difference between mower batteries, however. They are also usually categorized as being lead-acid and lithium.

“Lead acid batteries are cheaper, stronger and can handle the elements better and are usually heavy,” says lawn and garden expert Kody J. Ketterling, founder and CEO of at K-IT Products. “You have to always make sure they are fully charged, and the amount of times that you can charge and discharge are fewer.”

Lithium batteries, on the other hand are lightweight but more expensive. These require a special type of charging to ensure proper battery life.

“If a lawn mower has an alternator they will charge as you use them; this is usually a riding mower style,” adds Ketterling. “Smaller mowers do not usually have an alternator and you have to charge the battery periodically.”

How to know if a mower needs a new battery

Since mowers need battery power to run, you may be wondering how you know if yours is faulty. One of the most common signs is that the mower won’t start. “Before assuming this is the battery, make sure the machine is not isolated and is ready to accept power,” says Davies.

Still no luck? Test the battery on a charger. “Usually if your battery will not hold a charge you will need to get a new battery,” shares Ketterling. “If you put the battery on a charger and it will not fully charge, that usually signals that the battery is bad.” A battery not charging at all is also a sign it needs to be replaced.

What to look for when choosing a new battery

If you’ve determined that the battery is dead, it’s time to get a replacement! Two of the easiest ways to figure out what you need are by checking the machine’s manual or by matching the existing battery.

A smart place to start: “You always want to consider where the battery posts are on the battery,” suggests Ketterling. “Make sure the size of the battery matches the area that the battery will need to go on the mower. Look at the cranking amps on the battery to make sure that you match that so that the mower will not struggle and there is enough power to start the mower.”

Need to find and replace the battery on your riding mower? Find out how below:

It can also be helpful to consider the availability and interchangeability of your chosen battery. “Think about any existing power tools you may have, does the brand produce a battery mower so you can share you battery ecosystem across several different tools in your household?” says Davies. This can come in handy for other yard tools such as leaf blowers or weed wackers.

Finally, it’s best to stick with name-brand batteries to avoid issues down the line. “Most mowers have proprietary battery systems, meaning they are designed to use their own branded batteries,” adds Davies. For that reason, he recommends staying clear of aftermarket batteries as they can result in warranty issues with the battery or your machine.

To learn how to replace the battery in a gas push mower with an electric start, watch the video below:

What if the issue isn’t with the lawn mower battery?

A lawn mower

In some cases, especially if you’re dealing with repeated battery issues, you may find that your lawn mower is actually the problem. For instance, if you cannot keep the battery charged (even when new), or have to put a new battery in your machine every year, it may be better to replace the mower. “When you are spending more time getting the mower going and the battery working I would recommend getting a new mower as time is crucial,” adds Ketterling.

One thing you may want to keep in mind? The type of mower you have. This can affect whether it’s cheaper to continuously replace the battery or get a new machine. “In general battery mowers require less service and spare parts compared to gas machines so they do tend to last a long time but this decision will be down to the user,” says Davies. “If there are any safety issues with your machine then you should not use it and weigh up the cost of repair vs. cost of a new machine.”

How to extend life of a lawn mower battery

Battery charging symbols

Since a good battery is crucial to a well-running mower, it’s important to take care of it! There are a few things you can do to extend its life and maintain battery health. First, follow the manual! “There will be tips on extending the life of the battery in the manual and some brands suggest removing them from the machine in storage, especially long term storage like over winter where batteries can run flat over time,” shares Davies.

Next, try to keep your battery as clean as possible. It’s also recommended to blow a bit of air at the battery cavity after mowing once in a while to eliminate any debris. (Click through for more tips on how to clean a lawn mower).

Finally, ensuring the battery stays active is key! “Make sure that if you do not put a charger on the battery that you start the mower one time every couple weeks,” advises Ketterling. This will help keep your batteries working and they will last longer. Batteries can last 3-5 years for us.”

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