UniEnergy Technologies » Lawn Mower Battery Not Charging? (Reasons & Fixes)

Lawn Mower Battery Not Charging? (Reasons & Fixes)

It’s the middle of summer and you’re ready to mow your lawn, but when you go to start the mower, it just won’t turn over. You check the battery and it’s dead. Now what?

It can be so frustrating to find yourself in a situation like this. In this article, we will discuss some common causes of a dead lawn tractor battery and a bad battery charger, as well as how to troubleshoot and fix the problems. We’ll also provide some helpful tips for keeping your battery healthy during the colder winter months.

So don’t despair if your mower isn’t performing up to par – read on for some helpful tips!

Lawn Mower Battery Basics

Let’s start by looking at the basics of lawn mower batteries.

All lawn mowers have a battery, and most have a charging system that keeps the battery charged while you’re using the mower. The charging system includes a rectifier (which converts AC to DC) and an alternator (which charges the battery).

When the engine is running, the alternator produces electricity which is used to charge the battery. The rectifier then converts the AC power from the alternator into DC power, which is what the battery needs to be charged.

How to Troubleshoot Why Your Lawn Mower Battery Isn’t Charging

However, sometimes these mechanics don’t work as they should. If you’re finding that your battery keeps dying, then it may not be charging properly. If your lawn mower or lawn tractor battery is not charging, there are a few things you can check.

But before we look at them, there are precautions to take when working with electrical charging systems. Always make sure to:

  • Wear safety glasses
  • Wear gloves
  • Work in a well-ventilated area
  • Avoid heat sources or any sources that could cause sparks or flames
  • Inspect the charging system for debris or moisture
  • Keep the battery upright (don’t tip it)

Now that we’ve gone over some safety precautions, let’s look at some potential issues that could be causing your battery problems.

1. Is the Battery Properly Installed?

First, make sure the battery is properly installed and that the terminals are clean and free of corrosion. As you can imagine, if the cables on the battery are loose, or if there is corrosion, then the battery won’t charge as it should.

If you inspect the battery and do find that the terminals are corroded, you can clean them with a wire brush. If they are very corroded, you may need to replace the terminal posts or get a new battery.

2. Is the Charging Station Working Properly?

Next, check the charging system itself. Make sure the rectifier and alternator are working properly.

Is the Charging Station Working Properly?

  • Checking the Alternator

The first thing to do is check to see if that alternator is functioning correctly.

The way you know if a lawn mower alternator is working properly is if, while the engine is running at full throttle, the battery voltage is around 30 volts of AC power. You’ll check this by using a multimeter. If the voltage isn’t where it should be, then the alternator may be your issue.

  • Checking the Rectifier

If the rectifier isn’t working, then the battery won’t charge at all. This is because the rectifier converts AC power from the alternator into DC power, which is what the battery needs to be charged.

The rectifier has a red cable that travels toward the battery. To check the rectifier, turn off your lawn mower and use your multimeter to check if where that red cable connects to the rectifier to see if it is producing around 12 or 13 volts of DC power.

If it isn’t, there may be a problem with your rectifier, or the connection between the alternator and rectifier may not be secure. If it is, then you’ll want to be sure that the rectifier is properly connected to the battery so that the power is actually reaching it.

  • Checking the Voltage Regulator

If they seem to be fine, then the problem may be with the voltage regulator. The voltage regulator controls how much power is sent to the battery from the rectifier. If you have a failing voltage regulator, it won’t allow your battery to charge properly.

The voltage regulator is located between the rectifier and the battery itself, along the same circuit. To check the voltage regulator, you’ll need to use your multimeter to check the voltage at the regulator’s output terminal.

3. Is Your Battery Old, Damaged, or Faulty?

Another possibility is that the battery is not getting enough juice in one way or another. This can be caused by a number of reasons. It could be that the battery is too old or that it was damaged somehow. Or if it’s a new battery but still won’t charge, it is possible that it’s just a bad battery from the start.

If the battery is old or has been damaged, it may not hold a charge as well as it used to. And if the lawn tractor has accessories that draw power from the battery (such as headlights or a stereo), they can drain the battery even when you’re not driving the mower.

How to Fix Your Lawn Mower Battery If Isn’t Charging

Once you’ve determined why your lawn tractor battery isn’t charging, you can take steps to fix the problem.

1. For Old, Damaged, or Bad Battery

If the battery is old, damaged, or faulty, then you may need to replace it. Or, if it’s a more simple problem like the terminals being corroded, you can clean them with a wire brush or replace the battery posts if they are very corroded to see if that helps.

2. For Charging System

And if the charging system is not working properly, you can possibly fix it on your own if you are confidently skilled, or you may need to have it serviced by a qualified technician. You can replace parts of the alternator, rectifier, voltage regulator, or the battery cables to fix the problem along the circuit.

3. For Accessories

If the problem is with the lawn tractor’s accessories, you can try disconnecting them and see if that helps. If not, you may need to buy new accessories that don’t draw as much power from the battery.

Quick Tips for Keeping Your Lawn Tractor Battery Healthy

There are a few things you can do to keep your lawn tractor battery healthy and working properly.

  • First, make sure it is properly installed and that the terminals are clean and free of corrosion.
  • Second, keep an eye on the charging system to keep it clear of moisture and debris and free from damage.
  • And finally, if you have accessories that draw power from the battery, be sure to disconnect them when they’re not in use.
  • Also, store your tractor mower in a sheltered area to keep it out of the elements all year round.

Caring for Your Lawn Tractor During the Cold Winter Months

Caring for Your Lawn Tractor During the Cold Winter Months

If you live in an area where it gets cold in the winter, there are a few things you can do to make sure your lawn tractor battery survives the winter months.

  • First, be sure to clean the battery posts and terminals before storing the tractor for the winter. This will help prevent corrosion.
  • Second, if possible, store the tractor in a temperature-regulated and well-ventilated area to keep the battery from freezing.
  • And finally, if the battery is more than a few years old, consider have it serviced before storing the tractor for the winter.

This will help you avoid any surprises come springtime when you go to start up your lawn tractor again.

Frequently Asked Questions about Lawn Mower Batteries

You may be having a few questions come up as you do this investigative process. Let’s look at a few frequently asked questions about lawn mower batteries.

How can I tell if my lawn tractor battery is bad?

There are a few signs that your lawn tractor battery may be going bad. First, it may not hold a charge as well as it used to. Second, it may take longer to charge than it used to. And third, it may not provide enough power to start the engine or run the accessories at full capacity. If you notice any of these signs, it’s time to check and possibly replace the battery.

Can I use a car battery for my lawn tractor?

No, you should not use a car battery for your lawn tractor. Car batteries are completely different and are designed to provide a large amount of power for a short period of time, while lawn tractor batteries are designed to provide a small amount of power for a long period of time. Using a car battery in your lawn tractor can damage the charging system and lead to big problems.

Do I need to winterize my lawn tractor battery?

Yes, you should winterize your lawn tractor battery if you live in an area where the temperature gets cold in the winter. This will help prevent the battery from freezing and breaking.

In Conclusion

A lawn tractor battery not charging can be a frustrating surprise. It can be caused by a number of things, including a bad battery, a faulty charging system, or a problem with the lawn tractor’s accessories, for example. It is important to regularly check each part of the system – and now you know how!

As always, if it is still confusing or you don’t have the correct tools, please consult a licensed technician to help.

What other questions do you have about lawn tractor batteries? Let us know in the comments below.

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