What is the Voltage of a Lawn Mower Battery?

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It’s not surprising that some people might wonder what voltage a lawn mower battery is. Well, let’s dive into it. In this article, I’ll be answering that very question and sharing some tips on taking care of your lawn mower battery, along with why it’s essential.

I will also discuss the factors that can affect how long your battery lasts. So, if you’re curious about lawn mower batteries, keep reading!

How a Lawn Mower Battery Works

A lawn mower battery is a rechargeable component used to start a lawn mower. Each cell contains a positive lead dioxide plate and a negative lead plate immersed in a sulfuric acid electrolyte solution.

When the battery is charged, an electrical current causes a chemical reaction, converting lead sulfate back into lead dioxide and lead. During operation, the stored energy is released, creating an electric current that powers the mower’s motor. 

battery of Snapper XD 82V MAX Cordless Electric

The battery typically lasts for about one season, but it will depend on how often you use your lawn mower. To get the most out of your battery, I recommend charging it regularly and maintain it properly.

(Check out the best battery-powered lawn mowers today.)

Lawn Mower Battery Cells

All batteries have cells, whether they power a lawn mower, machine, or any tool. These cells hold the chemical energy, which converts into electric energy–giving power to the tool.  

The number of cells determines the voltage of the battery. For example, a 6-volt battery has three cells, while a 12-volt battery has six cells. 

6-Volt Batteries

6-volt batteries are the most common type for mowers. They are also lead-acid batteries made up of lead and sulfuric acid. They work by converting chemical energy into electric energy through a process known as “electrolysis.”

When lead and sulfuric acid combine, they create lead sulfate. When lead sulfate builds up on the electrodes in the cell, it reduces the efficiency of the chemical reaction and produces heat. This is why keeping lead-acid batteries clean and free from corrosion is important.

installing battery on a lawn mower

It’s also worth noting that lead-acid batteries should never be disposed of in landfill sites as they can leak dangerous chemicals into the ground. 

12-Volt Batteries

12-volt batteries are less common than 6-volt batteries but are slowly becoming more popular due to their longer lifespan and higher starting power. Like 6-volt ones, 12-volt batteries are also made of lead and sulfuric acid.

However, 12V batteries have twice as many cells as 6V batteries. So, they produce twice as much voltage.  

Battery Voltage Differences Between a Riding and Push Lawn Mower

While riding mowers with gas engines use lead-acid batteries, push mowers, and electric riding mowers use lithium-ion batteries.

The cost, range, and charging time of lithium-ion and lead-acid batteries differ. Lead-acid batteries are more expensive than lithium-ion and have a shorter lifespan. On the other hand, lithium-ion batteries are more energy-efficient and fast-charging.

Makita XML08Z

Although riding mowers don’t require a lithium-ion battery to start, they still rely on high-powered batteries for their power. For instance, electric riding mowers and push mowers use batteries with a higher voltage.

Most lithium-ion push mower batteries have almost five times the amount of power compared to riding mowers’ batteries. 

How Do You Determine the Voltage of Your Lawn Mower?

Battery Inspection

The first thing you need to do is inspect the battery. In its body, a line of text may say “12v7Ah,” which could mean that your 12-volt battery has seven amp-hours. Check the number next to the letter “V” to confirm its voltage.

Lithium-ion batteries are commonly used in lawn mowers and usually advertise the amount of voltage the machine can produce. However, some models use two batteries in combination, and this can produce a higher total voltage. So, keep an eye out for that if you’ve got a mower with some extra oomph.

Check the User Manual

The second step is to check the user manual of your lawn mower. This is where you can find the information about the voltage for your mower’s battery. You can identify which type of battery is used and whether it’s a lead-acid or lithium-ion model.

CRAFTSMAN M125 21-in Gas Push Lawn Mower

Battery Cell Count

If you find yourself without the user manual and you’re dealing with a lead-acid battery, no worries. You can still get to the bottom of things.

Most lead-acid batteries come with plastic caps that allow you to identify the cells. You can check on top of the battery where the acid and electrolyte mixture is added. Count the cells.

After you’ve counted the cells on your battery, multiply the number by 2 to get the voltage. For instance, 12 volts batteries have six cells, while 6 volts batteries have three cells.

Locate Your Lawn Mower's Serial Number

Lastly, if you’re still in the dark about your mower’s voltage, it’s time to do a little sleuthing. Look around the deck of your mower for the model and serial number.

battery of Worx WG779

Most of the time, these numbers can be found on a label stuck to the deck’s side. It’s hard to find, but most of the time, it’s located somewhere on either the front or rear of the mower.

After you have the serial number, you can go to your manufacturer’s page to check or look up the digital owner’s manual online, depending on the brand of your lawn mower. 


Can I charge my lawn mower battery using a 12-volt charger?

You can charge your lawn mower battery using a 12-volt charger, but it’s not recommended. A 12-volt charger is designed to provide 1 amp of current, while a typical lawn mower battery requires between 3 and 10 amps of current to charge adequately. 

Can I overcharge lawn mower batteries?

Yes, it is possible to overcharge lawn mower batteries. When a battery is overcharged, the electrolyte [1] can boil and cause the battery to fail. So it’s important to use a charger designed for your type of battery and follow the manufacturer’s instructions for charging. This way, you can maintain the efficiency of the battery while extending the lifespan of your lawnmower


So, let me break it down for you: when you’re in the market for a new battery for your lawn mower, you’ve got to pay attention to the voltage. Lawn mower batteries come in various voltages, so it’s important to know what voltage a lawn mower battery needs before buying one. It impacts everything from how well your battery will perform in extreme conditions to how long it will last before needing to be replaced.

When choosing a new battery for your lawn mower, consider the voltage to get the best possible performance out of your equipment. It’s also one of the best practices if you want to ready your mower for summer

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Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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