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How to Charge a Lawn Mower Battery: 3 Tips and Tricks

Person holding lawn mower battery

A lawn mower is an essential tool for yard work. However, the battery dies, which means you will have to constantly recharge it after using the lawn mower. Also, unless you live in a tropical or subtropical climate, you are likely to park your lawn mower for months. This means you will need to recharge it after prolonged periods of dormancy.

How you go about the process will count for either a longer life span for the battery or a shorter one. In this article, we will take you through the right steps to recharge your lawn mower battery and provide tips and tricks that will help you along.

Let’s dig in!

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Charging a Lawn Mower Battery the Right Way

Before checking out how to charge the lawn mower battery, let’s look at some of the factors that make for a great lawn mower battery.

  • Voltage: Nearly all lawn mower batteries run on 12-volt batteries. However, note that dated batteries can use 6-volt batteries. The best thing is to ensure you use a charger that matches your lawn mower’s voltage.
  • Amperes: The chargers’ amperes will influence the charging speed. However, there is a threshold for the ampere level for a lawn mower charger, which is 10 amperes and will damage the battery.
  • Useful Features: Some additional features can help with the battery’s lifespan, including jumpstart settings that can help bring dead batteries back to life.  Some will also shut off once your battery is fully charged.

There are a couple of ways to charge a lawn mower battery, including using a battery charger or a car charger.

1. Charging With a Battery Charger

Charging Lawn Mower
Image Credit: Anze Furlan, Shutterstock

If you use a battery charger for your lawn mower, here is the right way of doing it:

Protect Yourself Effectively

A mishap may occur while using a battery charger, especially in case of electrical problems. So, it is necessary to have proper protective clothing while charging it.

You should wear thick rubber gloves and keep metals and jewelry away from the work area.

Ensure the mower has no damage before you start charging, and in case of such issues, call an expert. Some of the problems may include frayed connections, cracks in the battery casing, and bloated, warped, or bulging batteries.

Use the Correct Voltage for the Job

Ensure you know the type of voltage needed for your battery charger. Some older versions may need a 6-volt charger, but most modern mowers will require 12-volt chargers. This will be found in the lawn mower manual or battery label.

The Amp-hours should also never be set above 10 hours.

Find the Location of the Battery 

To find the battery location, you will have to lift the mower’s seat in most lawnmowers. The manual will also help you find the battery location in case you cannot find it under the seat.

You do not have to remove the battery from the lawn mower to charge it, and you can leave it in place and connect the charger to it.

Connect the Terminals

This is an important element of the charging process, which, if done wrong, can have disastrous effects on the battery. You will first have to unplug the charger from the socket and connect the charger to the battery terminals.

The positive clamp from the charger should be connected to the positive terminals and the negative should be connected to the negative terminal.

Plug in the Charger

After ensuring the terminals are correctly connected, you can then plug in the charger and let it be until the battery is fully charged.

As a rule of thumb, check the charging after an hour, as it is the normal time it will take to charge the battery fully. Overcharging the battery can harm its lifespan, so remove it once fully charged. You can also go for chargers that will switch off automatically once the battery is ready.

Unplug the Charger

Finally, after the battery is fully charged, you can switch off the power and remove the clamps from the battery terminals for safekeeping.

2. Charging the Lawn Mower With a Car

Charging a lawn mower
Image Credit: JoshCampbell1, Shutterstock

You may be in a situation where you have no power but your vehicle is available. Is it possible to jump-charge the lawn mower battery with a car? Yes, you can charge the lawn mowers with a car, as most lawn mowers use 12-volt batteries, similar to vehicles. It is also quite a simple procedure that will not necessarily require an expert.

Before setting out, ensure that the battery is 12 volts. A 6-volt battery may permanently be damaged if you charge it with the car.

Get Proper Protection for the Job

You should get proper protective clothing and gear for the job, including thick rubber gloves.

Prepare the Mower

Get the battery uncovered. You may have to refer to your manual for this, as some batteries come covered.

Bring the Car as Close to the Mower as Possible

Bring your car closest to the mower to ensure the jumper cables can easily reach the mower and the car. In some cases, just having the car behind the mower is convenient.

Prepare the Car

Before opening the car’s hood, ensure the handbrake is engaged to avoid any incidents where the car starts rolling away or towards you.

Open the car’s hood and identify the battery’s location, remove the covering if there is one, and expose the terminals.

Connect the Jumper Cables to the Lawn Mower Battery

Attach the red clip to the positive terminal of your car’s battery and the other clip to the positive terminal of the mower’s battery. Attach the negative clip to the negative car battery terminal and the other clip to an unpainted metal on the mower away from the battery.

This prevents any sparks that may cause damage.

Start the Mowers Engine

As the mower does not draw much energy for it to start up, you may not need to get the car started. Head off to the mower and start the engine and see if it will start. If it does not, leave it for a minute or two to draw in some juice before restarting it.

If you choose to start the car, ensure the mower is off first and start the car engine.

Give It Time to Charge

Don’t be too quick to disconnect the jumper cables after it starts. Let it get some juice first for at least 5 minutes.

3. Trickle Charging a Lawn Mower Battery

Charging lawn mower
Image Credit: mdbildes, Shutterstock

Trickle charge current works to counteract the battery’s self-discharge rate, ensuring it keeps it charged when plugged in. Although this method helps maintain the charge level, it comes with a low output that is not good while charging the battery to full capacity.

Trickle charging works by operating two amps, making it take longer to charge the mower battery. However, once fully charged, it will keep it that way.

Since trickle charging takes a long time to work, it may not be the best option. This is because keeping the battery charging for prolonged periods may start wearing it down.

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Checking if Your Battery is Dead

Especially after winter, if the battery is not well stored and maintained, you may find it dead. But how can you be sure? Here is how to check if the battery is dead.

  • Check the Connections: Lawn mowers tend to vibrate a lot, which may loosen the terminal and leave you thinking the battery is dead. Lift the seat cover or locate the battery and check the terminals.
  • Charge It: You can try charging the battery for the normal time it usually takes to ensure it’s full. If you check it afterward and find that the battery is still low, you may have a dead battery on your hands.
  • Verify the Voltage: You can also check the battery’s voltage to check if it’s dead. This can be done by attaching a probe to the battery terminals and checking whether the readings are as the battery came with, normally 12 volts.
  • Check for a Clicking Sound: While starting the lawn mower, a clicking sound may be a good way to know the battery needs replacement. The clicking sound means the motor is trying to get power from the battery but not getting enough juice.

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Frequently Asked Questions

Is it necessary to remove the battery during winter?

Removing the lawnmower battery during winter may not be necessary, but it is advisable to remove it after charging it fully. However, you should also take it out and charge it occasionally during winter to ensure it does not freeze or lose all the power due to prolonged dormancy.

Do I need to disconnect the battery before charging?

It is unnecessary to disconnect the battery before charging, as it can charge while still on the lawn mower. However, if it is not charging and you suspect the battery may be dead, it may help to disconnect and charge it separately.

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In conclusion, most modern lawn mowers will not be hectic to charge. Simple monitoring and care will ensure your mower works with a full charge and the battery lifespan reaches its maximum potential.

Featured Image Credit: Cliff Day, Shutterstock


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