UniEnergy Technologies Battery » 5 Steps To Charge Lawn Mower Battery with Car

5 Steps To Charge Lawn Mower Battery with Car

After leaving your lawn mower idle for an extended period or during the winter months, your lawn mower can take quite a hit. This doesn’t only relate to the rate at which it cuts grass, but it can also affect the stored battery of your lawn mower.

When the time comes to use your machine, you might find out that the battery is too low and it might not start. Most lawnmowers utilize lead-acid batteries and they can discharge over time.

Fortunately, you can get your lawn mower’s dead battery back up and running with your car and have it fully functional again before the mowing season. In this article, we will be looking at the correct way you can charge your lawnmower battery in your car without any casualties.

How To Charge a Lawnmower Battery With A Car?

If you don’t have a battery charger, you can still use a car to charge your lawnmower’s battery. You need to make sure that both vehicles use a 12-volt battery. Then, follow these steps;

Step1. Place your car and lawnmower together

After making sure that your lawnmower is using a 12v battery, you should then place the mower and your car side by side, so that you can easily connect the charging cables. Make sure that the riding lawn mower battery is in range and then open the area of your car where the battery is located.

There are lawnmowers that have their battery placed towards the front, near the engine. While, in some other models, you will find the battery under the seat.

How To Charge a Lawnmower Battery With A Car?
Image Credit: poweredoutdoors

Step2. Clean Corrosion

You should not work with dirty battery posts as it could be harmful to both you and the lawnmower. So, if you notice that the battery terminals of the lawnmower are looking dirty, wipe them clean before moving on to any other step.

Also, cleaning any rust on the battery terminals with a battery terminal cleaner is very essential as it ensures that the battery does not lose power and also helps to establish a tight and perfect connection.

Step3. Connect The Cables

Once you are done prepping the battery and the car, you can now go ahead to connect the cables. Make sure the car’s engine is turned off before going ahead. You need to be extremely careful when you are connecting the battery terminals. There are two leads on a car’s battery, the black lead, and the red lead.

Connect both batteries using the jumper cable with these steps:

  • Connect the first end of the red lead to the positive terminal of the mower battery and then the second end to the positive terminal of the car battery.
  • Connect the first end of the black lead to the negative terminal of the car’s battery and the second end to an unpainted metal on your lawnmower. Note that it should not be close to the lawnmower’s gas tank or battery charging system. You can now turn on your car after connecting the cable.

Step4. Start The Lawnmower’s Engine

After making a tight and secure connection with the cable, you can go ahead to turn on your lawnmower’s engine. It should come on at this point. In the case where it doesn’t, do not tamper with the connection and allow the lawnmower’s battery to charge more before restarting.

Start The Lawnmower’s Engine
Image Credit: poweredoutdoors

It is important to note that the more “dead” your lawnmower battery is, the longer you will have to wait before you can retry. It is advisable to leave it hooked up to your car’s battery for at least five minutes to allow it to draw enough juice and energy.

Step5. Unmount all connections

Once your mower battery has been hooked up for five minutes, it has enough power to run the mower independently.

It is now time to disconnect your setup. For this, you will need to disconnect the cable in reverse order.

You start out by detaching the black clip from the lawnmower and then from your car. Then proceed to detach the red clips in that same sequence. You can turn off your car but take your lawnmower for a small drive around to properly charge the battery.

How To Charge Lawnmower Battery with Your Car Battery

If you do not have jumper cables and you still wish to kick-start your lawnmower using your car, then you should try using your 12v car battery. Let’s give you a detailed rundown on how to do that;

  • Remove your car battery and find somewhere secure on your lawnmower to keep it.
  • Next, tightly connect both terminals of the lawnmower battery to the car battery.
  • At this point, it should jumpstart your lawnmower, without any issues.

The idea of using your car battery is to get your lawnmower up and running. When this happens, it would no longer need your car battery, and after you disconnect it, it’ll still have enough power to run on its own.

How To Charge Lawnmower Battery with Your Car Battery

Important Factors You Need to Consider

  • If you are uncertain about the voltage of your lawnmower, refer to the manufacturer’s manual.
  • You can only jump start your mower battery if it has a 12v battery, but not a 6v battery.
  • Normally, you shouldn’t use open fire when close to your batteries or light a cigarette when charging your lawn battery, and that’s because batteries contain explosive gases.
  • When your cables touch any metal, it’s likely to spark and ruin the battery.
  • It’s vital that you clean the battery posts before jump-starting, or else it’ll be more difficult to power.


Those who use their lawnmowers frequently, they’ll experience battery issues from time to time. It’s normal to keep your mower stored during the winter, but the problem with this is that the battery might get drained.

If you don’t have a battery charger to power your mower, your car battery can do the trick. There are safety precautions you need to adhere to when doing this to ensure you don’t cause harm to yourself.

Lastly, if you want to keep your mower in the garage for a long period, remove the battery before storing it.

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