How to Charge a Lawn Mower Battery?

This post may contains affiliate links. If you click and buy we may make a commission, at no additional charge to you. Please see our disclosure policy for more details.

It will interest you to know that lead-acid batteries can discharge during prolonged storage after winter. If you own a lawnmower you are bound to face the problem of low battery power after storing it for a while.

This article on how to charge a lawn mower battery will take you through the required steps to get your mower running again.

Charging a Lawn Mower Battery

If the batteries are damaged beyond redemption you may need to change them but if they can accept a charge then you can use a regular car charger to charge them.

The most cost-effective way to charge a mower battery is by jump-starting it with the right instruments then allowing it to run for some time while the alternator system does the recharging job.

Don’t leave the batteries connected to the car because it can overheat or potentially cause an explosion.  

The two major ways of charging up your mower batteries are either using a battery charger or jump-starting with a car battery. Let’s explain these processes:

Charge a Lawn Mower Battery

Using a Battery Charger 

To use a battery charger to charge your lawn mower follow these steps:

#1. Remove the Battery

Remove the battery by disconnecting the terminals from the heads with a pair of pliers. If the batteries are held in place by a bolt, remove them by using a suitable bolt wrench.

#2.Ventilate the Area

Choose a well-ventilated area to charge the battery because harmful gases can be emitted into the air. As a precautionary measure, ensure you remove all sources of ignition to avoid an explosion.

#3. Connect the Charger to the Battery Terminals

To do this, the positive connector (+) should be attached to the red clamp while the negative connector (-) must be attached to the black clamp. Once you have done this, then it is safe to plug the battery charger to begin the charging process. Monitor the LED display screen or the light system to get notified when the battery has completely charged.

#4. Unplug the Charger

Once the battery has fully charged, unplug the battery and replace it in reverse order.

Advantages of using a battery charger

  • Battery chargers are more effective at regulating the pace of charging. They communicate with the target battery and reduce the input current once the target charge is reached.
  • Prevents overheating or overcharging batteries
  • Using a battery charger is less likely going to produce lead chemical spills
  • They regulate the input charge to ensure the battery doesn’t charge up too quickly.

Jump-Starting the lawn mower

Jump-starting your lawn mower is the next option for you if you don’t have a battery charger.  It’s actually safe to jump-start a riding lawn mower by using a car battery However, make sure the riding lawn mower battery is 12-volts. After jump-starting the lawnmower allow it to run for an hour or two to allow the alternator to do the rest.

Alternators act like traditional battery chargers. Follow these steps to jump-start a riding lawn mower with a car:

1. Move the car close to the mower:  Park your car very close to the riding lawn mower and open the hood. Also open the battery compartment of the riding lawn mower and use appropriate tools to remove the terminals.

2.Connect the cables: Strictly follow these instructions to connect the cables:

  • The positive terminal of the riding lawn mower battery connects to the red lead
  • Connect the other end of the red leads to the positive terminal of the car battery
  • The black lead connects to the negative terminal of the riding lawn mower
  • Subsequently, the other end of the black lead connects to the negative terminal of the car battery.

3. Start the Lawn Mower: Now start the lawn mowe​​r to see if the engine picks up. If the mower doesn’t start, leave the connection in that order for about two minutes. This should help revive the dead riding lawn mower battery. Try again after two minutes to see if it works. As soon as the mower starts up, disconnect the cables in the reverse order i.e. disconnect from the car before removing them from the mower battery.

Jump-Starting Precautions to Observe

  1. Only riding lawn mowers (Heavy-duty) should be jump-started with a car battery. This is so, because the batteries in riding lawn mowers are big enough to accommodate the input current from car batteries.
  2. Do not leave the riding lawn mower batteries hooked to the car batteries after the jump-starting process is over. Car batteries are significantly more powerful than riding lawn mower batteries.
  3. The use of car batteries is an unregulated charging alternative to battery chargers. So only attempt this if you don’t have a battery charger.
  4. Do not leave the car running after jump-starting the mower battery. There is a significant danger of overheating and damaging the car battery. You need to turn the car off because the car’s alternator system is stronger than the mower’s alternator.
  5. Disconnect the cables once the jumpstart process is over. If you leave the cables on you can easily drain the car battery.

Final Thoughts

Occasionally, lawn mower owners are faced with the challenge of charging mower battery from prolonged storage after the winter cold.  

If you don’t own a battery charger and you have a riding lawn mower with compatible battery, opt for the jump-start technique.

However, we highly recommend that you purchase a battery charging kit because it’s the safest.

Leave a Comment