How To Troubleshoot A Lawn Mower Battery That Won’t Hold Charge

Have you ever experienced a situation where your lawn mower battery constantly fails to hold the charge? If yes, you might be eager to know, is it possible to troubleshoot such battery failure; and if possible, you might be wondering how?

Firstly, gather up all the necessary tools and materials required to perform the troubleshooting. Then, check whether the charging system is working properly or not by testing with a multimeter. Next, check the current state of the alternator, voltage regulator, and battery. Repair or replace the faulty elements.

Read the article till the end to learn how to troubleshoot a lawn mower that won’t hold charges.

What Causes the Problem?

If the lawn mower battery fails to keep the charge, there must be an issue in the charging system, or the battery might be draining the power while the engine has been turned off.

A lawn mower won’t hold charges as it is supposed to due to dirty, loose, or corroded internal battery cables, electronic drain, or dead battery.

A similar situation can also arise charging system failure or a failing voltage regulator.

However, you cannot and should not verify the actual problem without a thorough investigation.

4 Steps To Troubleshoot A Lawn Mower That Won’t Hold Charge :

Imagine you are about to start mowing, and suddenly you notice that the battery is not holding charges. Nothing can be more irritating than such kinds of situations and you need an effective yet quick-fixing solution to deal with this unpleasant trouble.

Thus, I have enlisted an easy-to-do yourself technique to troubleshoot such issues and fix the problem without causing any further troubles:

Things you will need:

Have a glance at the checklist of the required tools or materials to troubleshoot a lawn mower that won’t hold the charge:

Standard Mechanical ToolboxAlternator/Stator
Voltmeter/ Digital MultimeterRectifier Regulator
Safety Goggles & GlovesBattery

Step 1- Check if the Charging system is working:

Before starting the whole troubleshooting procedure, wear safety goggles and gloves.

As soon you notice the battery failure or dead battery on your lawn mower, the first thing you should confirm is to check whether the charging system is working properly or defective.

To do that, hook up the voltmeter or Digital Multimeter with the battery connecting wires to check the reading of the battery’s DC volts.

Next, start the engine, and check the reading displayed on the voltmeter screen.

Remember, it should show around 14 volts at full speed. If it is displaying below 14 V, it must be occurring because of either a defective alternator or voltage regulator.

Note: Be sure about your technical knowledge and expertise before you start the process. If you are not confident enough, better to get professional assistance. Otherwise, you might worsen the condition of your mower due to your lack of knowledge.

Step 2- Check the current state of the Alternator or Stator:

Next, you need to check whether the stator is producing enough AC and whether that current is going through the yellow pigtail or not.

So, use a multimeter or voltmeter and connect the probes with the stator wires. Now, start the engine at full RPM and check whether you are getting the highest AC or not.

If the stator is not producing any AC current while the engine is running at full RPM, inspect whether there’s a loose or broken wiring connection.

In that case, either tighten the slacked wiring connection or replace the faulty wires.

If it looks severely damaged, better to just replace the Alternator/Stator.

If the voltmeter screen shows that the alternator/stator is producing AC, inspect the regulator.

Step 3- Inspect and Test the Voltage Rectifier Regulator:

If the alternator or stator is working perfectly, then you should check whether the regulator is taking that produced AC converting into around 13 to 14 Volts DC or not.

First, set up the volt or multimeter at 20 scales. Then, hook up one of the probes to the regulator red lead and plug that pigtail.

Also, ground up for the negative and start the engine to see how it goes.

Now, if the meter shows a low volt, that means the rectifier is not producing enough DC voltage, and all you need to do is replace the Voltage Regulator.

Or, you can visit Walmart to pick the right type of regulator replacement kit for your particular lawn mower model.

Note: Sometimes, the rectifiers are not grounded accurately, and if the rectifier is not grounded properly, the battery will fail to hold the charge. Thus, ensure that the rectifier is grounded correctly.

Step 4- Replace the Battery:

Now that you have fixed the defective alternator, wiring connections issue, and bad regulator problem, again check the battery voltage to determine whether the charging system is working correctly or still having the same problem.

This time, when you start up the engine, ensure the meter shows more than 13 or nearly 14 volts on the screen. If the meter displays lower voltage, just like it showed before, you might have to replace the Battery.

Even after following all the instructions step by step, if you still see the same battery failing issue, it’s better to contact your nearest workshop.


Always read your lawn mower’s instructions manual first before operating, servicing, or troubleshooting it. Keep the engine shut off and disconnect all the power sources before starting the thorough inspection.

Watch this Video.

Frequently Asked Questions

What causes a battery-powered lawn mower frequently die?

A battery-powered lawn mower can die because of several reasons such as loose, corroded, or dirty battery wires and cables, electrical system malfunction or draining, and broken or dead battery.

What helps the battery to stay charged on a lawn mower?

An alternator or stator circulates power back through the system while powering the lawnmower engine, and this process keeps the battery charged.

How long does a lawn mower battery last?

Generally, a lawn mower battery will last three to four years.

Do lawn mowers feature alternators?

Electric-powered push mowers do not have alternators or stators, but mowers with a gas-powered engine with a battery-powered electrical system have an alternator.

Final Verdict

Battery not holding charges and causing engine starting failure or frequently shutting down issues are pretty commonly mentioned lawn mower problems.

Now that I have explained all the steps to troubleshoot a lawn mower that won’t hold charges, you can easily get your lawn mower back in perfect running condition within no time.

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