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Lawn Mower Battery Charging Times Explained

The start of summer means that it is time to bring out your lawn mower to keep your yard well manicured. If your mower was in storage during the colder months, the battery could have drained, and you will want to keep the battery charged throughout the season so that you are prepared to mow your lawn. 

A fully charged lawn mower battery will typically last one hour. Fully charging a lawn mower battery, especially with a trickle charge, will take more time, but will reduce the frequency with which the battery needs to be charged and improve your battery’s health.

Taking care of your lawn mower’s battery will maintain its longevity, however, there are many factors that go into charging your lawn mower. Not only will you need to consider the health of the battery, but the health of the lawn mower as well.

In this article, we will explain what affects your lawn mower charging time.

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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing or operating. Consult a professional if you don’t have the skills, knowledge or are not in the condition to perform the repair safely.

What Affects Lawn Mower Battery Charging Times?

The voltage of the battery, the amps needed to charge it, and how often you use will affect how long you need to charge your lawn mower battery. It’s important to understand voltage and amperage to better understand your battery and how it charges.

The Voltage of the Battery

A battery has a positive and negative electrical charge to it, and the difference in the potential of these terminals is the battery’s voltage. The voltage you use in your lawn mower’s battery will impact how long it takes to charge and how long it will last in between charges.

The voltage of your lawn mower’s battery will depend on these factors:

  • How large your mower is
  • When your mower was produced

Lawn mowers produced in the 1980s will most likely use a 6 volt battery, which has a shorter charge and usage time.

How Voltage Affects Charging Time

The time it takes to charge your battery depends on the voltage, and for all voltages, you need to charge the battery slowly to keep it safe and efficient. You can make your battery last longer when you avoid overheating and overcharging it.

This is why you should trickle charge your battery, as this improves the longevity of the battery while reducing the likelihood the battery will overheat and overcharge. 

Depending on how much it has been used in between charges, a 6 volt battery can take up to 6 hours to charge and a 12 volt battery can take up to 12 hours to charge.

The Amperage Used in Charging

Another major factor in your lawn mower’s battery charging time is the amperage. Amperage is the strength of the currents measured in amperes, which is also called “amps.” The amps measure the current that charges the lawn mower’s battery.

The average charger for your lawn mower’s battery will have a current of up to 10 amps. This is a lower current, so it will take your battery longer to charge than a higher current.

This current is recommended because it protects the life of the battery. Some chargers can charge your lawn mower battery at a current of 20 amps, and this will reduce the charging time.

While this output is larger, it can unfortunately damage the battery, especially if it is used regularly. It is much better to use a current of 7 amps or less. It will take longer to charge, but it will also allow your battery to last longer. 

When charging your battery at 6 or 7 amps, you should be able to use your battery within an hour. Raising or lowering the current will shorten or lengthen your charging time.

This is why a charger with a current of 7 amps is the best because it benefits your battery’s life by reducing the current while also having a speedier charge time than lower amps.  

The Frequency of Use

How often you use your lawn mower can be an unexpected factor in how long your battery needs to charge.

You might expect your lawn mower to stay charged while in storage, however, the battery can drain, even if you are not using it. If your lawn mower has not been used all winter, you might not be able to turn it on right away.

Some drainage can be normal for a lawn mower battery, but make sure that there are not any major issues, like:

  • Leaving the mower on
  • Keeping keys in the ignition
  • Age-related current draw

If you leave the keys in the ignition, you could forget to turn the mower off or your mower could be staying in standby mode. This means that you could be draining extra power when you might think it is stowed away.

Always double check to make sure that the keys are not left in the ignition after using a lawn mower. You also might want to check that there is not an unnecessary current draw when the lawn mower is turned off. Batteries that are older will lose a charge much faster.

If your battery drains too quickly, it might be time to replace it. A battery that is in good condition will hold onto most of its charge with minimal charge leakage. The more charge your lawn mower is leaking, the worse condition your battery is in. 

The Run Time of the Lawn Mower

How long you have your lawn mower on will also affect how long and how frequently your battery needs to charge. Larger capacity batteries will take longer to charge, but they can run longer in between charges.

The run time of your battery is closely related to the voltage and age. Fully charging a lawn mower battery will take longer than charging it for a single use. The higher the voltage of the battery, the longer it will take you to charge it to its full capacity.

This is why the 12 volt battery is the standard for most lawn mowers. It provides a good balance between how long it runs and how long it charges. You will spend less time charging this battery, and you will not have to charge it as frequently.

What is Causing My Lawn Mower Battery Life to Drain?

The life of your battery can keep draining if your battery isn’t making good connection due to bad or corroded terminals and loose cables. Leaving your ignition key in the on position or a faulty charging system can also affect your battery.

Learn more about how to check and charge your battery along with checking your lawn mower’s charging system here.

How Can You Make Your Lawn Mower Battery Last Longer?

Lawn mower batteries can last several years and require little maintenance. To ensure that it lasts the longest it can, you should:

  • Charge it appropriately
  • Use the best voltage for your mower
  • Keep it clear of corroded materials

To charge your battery appropriately, you should use a lower amperage. Charging the battery at 7 amps is recommended, and lower amps are even better for its longevity.

Even though a higher amperage can charge your battery faster, it can also seriously damage it, so avoid the temptation of going over 7 amps. 

You should also make sure your battery’s voltage is right for your machine and use. Use the battery recommended by your lawn mower manufacturer. Most lawn mowers use a 12-volt battery.

Keep your lawn mower battery running by keeping it clear of corrosion. The gasses from the battery combined with high temperatures can corrode the battery, and this can affect the battery’s life if it is not taken care of. You can easily remove corrosion by using a wire brush on the affected areas.

How Caring for Your Lawn Mower Affects Battery Life

Treating your lawn mower right will benefit your battery as well. This means checking on the engine regularly, checking for any problems with the blades, and monitoring the health of your battery as well.

When you care for the entire machine, you will prolong your lawn mower’s battery and save money. Keep your blades sharp so that you do not have to use the lawn mower as vigorously.

Dull blades will take longer to cut grass, which means you will have to drain your battery more. A simple fix could be that your blades need to be sharpened.

Sharp blades will cut grass much easier and require less exertion from you and the battery. You can do this with metal files, chisels, or a blade sharpener if you have one.

Treat the lawn mower right during different weather patterns. Protect it from the rain and snow by keeping it stored in a secure place.

If you forget to put away your lawn mower, it can get rusty or the battery can get damaged. You will save yourself from unnecessary expenses by keeping the mower protected. 

Do not mow wet grass and be careful not to run over major debris in your yard. These things can clog the lawn mower and grass, messing up the lawn mower and the grass. You should also keep the battery from getting wet to avoid water damage and electrical shocks. 

How Do You Trickle Charge a Lawn Mower Battery?

Most battery chargers will deliver a current of up to 10 amps to the battery because it is a combination of a safe and quick way to charge the battery. A trickle charger is a great alternative to regular chargers because it will charge your battery at a very slow pace for a longer time. This protects the battery by:

  • Preventing overcharging
  • Keeping the battery from draining
  • Protecting the battery from temperature and sulfate damage

When a lawn mower battery is overcharged, the battery can get damaged and need to be replaced faster. Some regular chargers will shut off automatically when it has reached a full charge, but for those that do not, you will have to remember to take the charger off the battery. 

Even if the charger can shut off on its own, leaving the battery to sit for extended periods of time can still lead to the battery draining. Batteries that are not used for a long time can be damaged by sulfation.

Additionally, if the lawn mower is in a shed or garage over the winter, the cold weather can crack the battery.

Trickle chargers keep the battery constantly constantly charging by delivering a slow and steady charge. This will greatly increase the charging time, but it will protect your lawn mower’s battery by keeping it steadily charged and warm, even when it has been put away.  

How Trickle Chargers Work

Trickle chargers deliver 1-3 amps to your 6 or 12 volt lawn mower battery. This very low current means that it is slowly charging the battery while keeping it safe.

It is a good idea to keep your lawn mower on a trickle charger when you are using it regularly so you do not have to worry about taking the charger off.

You begin to use a trickle charger for your lawn mower like a normal charger:

  • Unplug the charger from the outlet for your safety
  • Connect the positive side of the charger to the positive side of the battery
  • Connect the negative side of the charger to the negative side of the battery
  • Make sure the voltage is correct on the charger
  • Plug it back in

Most trickle chargers are automatic. When you begin to connect your charger, it will detect the battery’s voltage and charge level to maintain it. The charger will handle the battery on its own from there. Fully charging your lawn mower battery will take up to 24 hours on a trickle charger.

The slow continuous charge is good for protecting it throughout the year. It is recommended to put the charger on well before you want to use it during mowing season so that you do not have to wait for it to charge.

It is also good to keep the charger on during the colder months so that it does not freeze and get damaged. 

Conclusion

Your lawn mower is a great tool for maintaining your yard during the warmer months. With a little maintenance and charging throughout the seasons, you can keep it running for years.

You have to understand your lawn mower and its battery so that you can care for it properly. Simple tools like trickle chargers will be great for caring for the lawn mower’s battery because you have to attach it and it does the work for you.

The extra investment you make in caring for your lawn mower by keeping it clean and charging it properly will ultimately save you money and keep your lawn mower going.