Why Is My Lawnmower Battery Dying? How To Fix It?


Lawnmower batteries either come 12-volt or 6-volt. Though they have similar functions to automobile batteries, they are smaller in size. The primary job of a lawnmower battery is to help you start the engine by providing sufficient power.

Why is my lawnmower battery dying?

A lawnmower battery may die for several reasons such as a faulty voltage regulator, loose connection with battery or battery post corrosion, etc. 

  • A voltage regulator that’s not functioning
  • Lawnmower not working at full power
  • A loose connection
  • Battery post corrosion
  • Excessive consumption of electric power

Why Is My Lawnmower Battery Dying?

Why Is My Lawnmower Battery Dying

Suppose you are using your lawnmower smoothly, but it suddenly stops running. You have checked out all the parts, and the connections are okay. So, what is the possible reason it could be?

Plus, you have fully charged the battery, but it didn’t show any issue while charging. Simply put, you are wondering about this question, why is my lawnmower battery dying?

Here are few possible reasons your lawnmower batter may have.

1. Voltage Regulator is Not Functioning

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If the voltage regulator is not functioning as it should be, it may cause to dying battery issue. A functional voltage regulator along with an alternator helps the battery to recharge.

Having problems with the regulator may make the battery die too quickly. Hence, you will not get enough backup to start the lawnmower smoothly.

2. Lawn Mower Not Working At Full Power

It is also possible you’re not cutting grass at full throttle while using your lawnmower. When you run the lawnmower, make sure you’re running it at the maximum throttle.

So, why do it? It is because it is the best way to achieve the RPMs needed to charge the battery. When the RPM rate falls, battery charging deficiency will occur. You may experience lawnmower battery death between mowings due to this issue.

3. A Loose Connection

lawn mower battery is loosely connected

It might be unnoticed to you, but there is a possibility the battery is loosely connected. A loose connection happens when the wires of the battery are not correctly connected.

A loose connection either gives no support to the battery or the battery struggles to work smoothly. It may lead to battery drainage or dying issues quickly.

In that case, you want to check out on-hand whether all connections are correctly plugged in or not.

4. Battery Post Corrosion

Battery Post Corrosion - Why my lawn mower battery is dying

White powders that build around the terminals of your battery can be a sign of trouble. Just because there is corrosion on the battery surface doesn’t mean it is dead. However, you can count it as an alert and check it quickly.

Sometimes you may need to replace the case of the battery if there is any crack. The crack mainly occurs due to the gas emission of the engine. Make sure to clean the battery posts properly.

5. Excessive Consumption of Electric Power

You might have already known that power is supplied to mower components such as headlights and horns by the mower’s electrical system

However, the battery energy is used even after the motor has been turned off. Hence, the battery will die quickly if you keep on the headlight or horn switch, making the battery drain faster.

6. Damaged Battery

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If your lawnmower battery is partially or almost damaged, it is high time to replace it. It might be already lost its capacity to hold enough charge. So, its life cycle is going to meet the endpoint.

When your lawnmower battery is damaged, the charge doesn’t last long as it used to be. An important piece of information you should know is that the life expectancy of most lawnmower batter is around 3-5 years.

With proper care, you can use the battery for up to 5 years. You want to keep the battery separated during the winter season when you are not using it. In addition, keep it a safe place where no freezing will occur.

So, these are all possible reasons for this question: why is my lawnmower battery dying?

What Would Drain A Lawnmower Battery?

Most lawnmower comes with a lead-acid battery. When you fail to start the machine, a drained battery may be a probable cause of this issue.

Your lawnmower is supposed to charge the battery when you are operating the machine. Sometimes it happens your lawnmower is draining the battery though you are not using the mower.

Different reasons can cause the question of what would drain a lawnmower battery.

1. Forget To Turn Off The Headlight

What Would Drain A Lawnmower Battery - Forget To Turn Off The Headlight

One of the possible reasons is to forget to turn off the headlight after using the mower. When the headlight is on for a long time, the mower battery keeps draining.

Some lawnmowers may have a smart system to turn off the headlight when the machine is not used for an hour or any specific time. However, if your lawnmower doesn’t have this feature, the battery will keep draining until you turn it off.

2. A Short Circuit

What Would Drain A Lawnmower Battery - A Short Circuit

The lawnmower battery may be drained by too much current draw caused by a short circuit. In that case, you want to check out whether there is any loose connection for the charging systems.

3. Too Hot or Cold Temperature

When the outside environment is too hot or too cold, it may show issues for your mower battery. If you purchased the battery recently, it could withstand more extreme temperature fluctuations in the seasons.

On the contrary, old batteries won’t be as effective as new batteries. Because they will be vulnerable to extremely hot or cold temperatures. The charging cycle may slow down.  And, the battery may die eventually as it can’t withstand the temperature.

4. Not Charging While Mowing

Why Is My Lawnmower Battery Dying

It is a common function for a mower battery to get charged when the machine is on. The alternator helps charge the battery.

If the alternator is not working correctly, the battery may not be charged. As a result, you will struggle to run on the machine.

Unless there is sufficient power on the battery, you won’t be able to start the mower. So, figure out whether any problem with the alternator.

5. Cranking The Mower Excessively

A considerable amount of power is required to start a lawnmower. Using your mower for a short time frequently may stop the alternator from charging the battery.

Though an alternator is supposed to charge the battery, it can’t do it because you are running only briefly.

The problem mainly occurs among the old batteries as they don’t have much resistant power like new batteries. Plus, newer batteries are equipped with the latest technologies for fast charging when the machine is on.

6. Decrease In Performance

You can’t expect the same level of performance from a battery. Over time, its quality will deteriorate, and the charge cycle will also decrease.

After a particular time, the mower battery will be completed damaged. Then the battery needs to be replaced.

So, this list contains all the reasons for this question: what would drain a lawnmower battery?

How Long Should A Lawnmower Battery Last?

There is no such thing that lasts forever, and it is also true for a lawnmower battery. After a specific time, you will have to charge the battery.

How long should a lawnmower battery last?

The life expectancy of a lawnmower battery is around 4-5 years with proper care.

Your mower battery lifecycle depends on

  • How properly it is cared for
  • How good the battery cell is
  • How frequently you used the machine

Gradually, you will notice the battery performance is decreasing. Because there is no longer as much battery life as there used to be. Regularly using your mower gives you an idea of the perfect time for replacing the battery.

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Some batteries may show less charge holding capacity within a short time. Under this situation, possibly bad battery cells are to blame. If your mower has a warranty, you should contact the manufacturer to demand replacement or repair.

Lastly, without adequate care, the battery will drain fast no matter how good the battery quality is. Hopefully, you have learned everything about this question: how long should a lawnmower battery last?

Why Won’t My Lawnmower Battery Hold A Charge?

A lawnmower battery is supposed to hold a charge for a reasonable amount of time so that you can start the machine. Have you ever experience this situation: your lawnmower battery drained even after using it only once or twice?

Why won’t my lawnmower battery hold a charge?

Multiple factors can cause the reason for a run-down battery

  • Your battery charge is consumed by headlamps or horn of your mower when it is off
  • While using the mower, its battery is not recharged
  • The alternator of the mower is not functioning properly
  • The lifecycle of the battery comes to an end (need a replacement)
  • The battery has a defective or blown fuse

So, these are probable causes when you are wondering—why won’t my lawnmower battery hold a charge?

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Why Do Lawnmower Batteries Not Last?

Why do lawnmower batteries not last or why is my lawnmower battery dying – whatever ask, the problem is is crucial.

As we have already mentioned, lawnmower batteries will not last a lifetime. As long as it holds the charge to start for the machine, you can use it. But when you notice the charge cycle is not up to the mark you desired, it may be an early indication to change the battery.

Here we are discussing some key factors of this question: why do lawnmower batteries not last?

1. Limited Lifespan

You have already known that lawnmower batteries can last up to 5 years. But the lifespan can be short than five years—

Serial No. Reasons
1 If the battery quality is not good
2 If you used the machine heavily
3 If you failed to follow proper maintenance

2. Environmental Conditions

According to garden experts, lawnmower batteries’ long-lastingness depends on environmental conditions. If you live in too much heat weather conditions, the battery will die faster than in colder areas. However, lawnmowers are not heavily used during the winter season.

3. Excessive Vibration Of The Mower

Does your lawnmower vibrate excessively when you use the machine? A battery has several cells. Parts of the battery may break down due to high vibration.

To prevent the battery from moving, you can use special hardware. When the battery moves too much, its wires may become loose, which will cause poor conditions.

4. Malfunctioning Charging System

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A malfunctioning charging system is not a common thing, but it can happen for your mower. When this problem occurs, your mower battery either becomes over-charged or under-charged. Plus, the function fails to control the charging rate of the battery.

Both cases will affect the lifecycle of the battery. As it is a technical issue, you may not understand it unless you are an expert in this field.

5. Installing Incorrect Replacement Battery

After a particular time, we need to replace the battery and ensure that you didn’t make any mistake installing it.

Most lawnmower comes with lead-acid batteries, but few of them have exception too. Because it depends on the manufacturer preference—which type of battery they want to use.

It is best to choose the battery recommended by the manufacturer. Installing the wrong type of battery may affect the engine’s performance. And it may be far away from the expected performance, unlike the old battery.

6. Installing The New Battery Incorrectly

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It is said you shouldn’t touch things that you are not master on it. If you don’t know how to install a battery in a lawnmower, it is better to let the professional do it.

Installing a new battery incorrectly may decrease the battery’s lifespan even though the battery is helping to start the engine.

But it will not continue for long, and that’s why you want to hand over the task to an expert. Either take it to a nearby shop or get a professional service at home.

So, it is essential to know— why do lawnmower batteries not last? You can take the right step to handle the situation based on the cause.

Can You Fix A Dead Lawnmower Battery?

fixing a dead lawn mower battery

A lawnmower battery is supposed to provide service for a particular time. Once the time is over, there is no going back, and you can’t fix it. However, sometimes you may mistake the battery condition and think it is fully damaged (but actually not).

Can you fix a dead lawnmower battery?

Whether you can fix a dead lawnmower battery or not depends on how ‘dead’ the battery is. Unless the battery is entirely defective, you can charge the battery with a rectifier for several hours and take a “load test” for the battery.

If the battery doesn’t face any issue for the “load test,” you can use it again for your mower. Several decades ago, it was common for technicians to replace the defective cells in dead batteries.

However, as the technology improved, it is an uncommon practice to do it. Plus, plus the process is time-consuming. Replacing is the best if the battery is completely damaged.

In addition, due to the smart system on the latest battery, even if some battery cells are defective, you can use the battery as long as other cells are fine. Hopefully, the fixing concern of this question is gotten cleared: can you fix a dead lawnmower battery?

How Do You Start A Lawnmower With A Dead Battery?

A dead battery doesn’t always mean it is completely damaged. Unless it is entirely defective, you can start your lawnmower.

How do you start a lawnmower with a dead battery?

Starting a lawnmower with a dead battery requires several steps to do.

  1. First of all, make a baking soda solution and use it to make the battery-free from corrosive material.
  2. Check if all battery connections are exemplary and there is any crank issue.
  3. Charge the lawnmower battery with a compatible charger.
  4. Check out the voltage
  5. Now, try to start the lawnmower.

Can A Lawnmower Battery Be Recharged?

Aside from knowing why is my lawnmower battery dying, it is essential to know can a lawnmower battery be recharged. A lawn battery gets the necessary charge when you use the lawnmower. However, when there are some internal issues, it may not get charged fully or appropriately.

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Can a lawnmower battery be recharged?

If your lawnmower battery is completely dead, you can charge it for a few hours using an external charging system. But make sure the charger is compatible with the mower battery and doesn’t cause any harm to the battery.

If you don’t know whether your mower is compatible with the charger, take expert help.

How To Fix Dead Lawnmower Battery?

Why is my lawnmower battery dying? – We have answered you what you need to know. But know let’s see how to fix a dead lawnmower battery.

Whether you can fix a lawnmower battery or not depends on the battery conditions. You can go through these instructions to know how to fix a dead lawnmower battery.

  1. Check if all the battery connections are okay — if not, fix them.
  2. Use a lawnmower charger to charge the battery and see if it shows positive signals.
  3. Use a multimeter to verify the charging rate and the accurate battery voltage.
  4. Fill up the reservoir of the lawnmower battery with water if the level decreases.

If nothing of this solution works on how to fix a dead lawnmower battery, you need to replace the lawnmower battery.

Wrapping Up

So, are you still wondering about this golden question: why is my lawnmower battery dying? We have outlined all the potential reasons which could lead to battery death.

Last update on 2021-10-07 / Affiliate links / Images from Amazon Product Advertising API