How to charge a lawn mower battery with a car the right way

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Learn how to charge a lawn mower battery with a car like a pro…..

Winter is never a good season for your lawn mowing pastime: not only can’t you make those cute cuts on grass, but can also harm your stored mower’s battery.

Luckily, you can use your car to bring it back to life and have your mower roaring (and cutting) again when the mowing season returns.

Below we show you how to charge a lawn mower battery with a car so that you can take up your thrilling grass trimming hobby once more.


How to charge a lawn mower battery with a car – step by step

Before we start, I must say that this works because most riding mowers use a 12v battery just as vehicles.

I should add that the steps are quite simple and even those who have zero technical knowledge should have minimal problems reviving their lawn mower battery.

Let’s get started:

How to charge a lawn mower battery with a car- jump starting method

The first solution that comes to mind when faced with a dead riding lawn mower battery (or push mowers) is to jumpstart it.

Here is the procedure to follow assuming you have checked that your mower is equipped with a 12-volt battery (jump starting a 6V battery with a 12-Volt car battery can permanently damage it):

Step 1: Prepare the mower

Get the mower ready by uncovering the battery to access the terminals (some mowers have a protective cover and you should refer to your operator’s manual for the right steps to follow to remove it).

For starters, the battery is located under the operators’ seat in nearly all mower brands.

You may also find it in a central position on the mower frame.


Step 2: Bring the car as close as possible to the mower

Drive your car the closest possible to the mower.

This is important because it lets the jumper cables easily extend from the car’s battery to the weak battery in the mower.

For most people, having the car stand just behind the mower is more convenient for this operation.


Step 3: Prepare the car

Switch the car ignition off and ensure the brake is engaged (you don’t want the car to roll away in the midst of the process!).

Now open the hood and identify the car battery’s location (check your owner’s manual for directions if struggling to locate the battery).

Remove the plastic cover (if any) to gain access to the terminals.


Step 4: Connect the jumper cable to the lawn mower battery positive and negative

Hook up the two batteries with the jumper cable as explained below:

  • Attach the first red clip to the + (positive) terminal of your mower’s battery.
  • Attach the remaining red clip to + (positive) terminal of the car’s battery.
  • Attach the first black clip to the – (negative) terminal of your car’s battery.
  • Attach the remaining black clip to an unpainted metal somewhere on your mower (but far from the lawn mower battery charging system and the gas tank). The hitch-on the back of your mower-is one popular spot.

Side Note: While connecting the other black clip to the mower batteries still works, it’s not the safest way of doing things because of the heightened risk of causing a battery explosion. On the other hand, hooking it to a plain metal surface grounds the circuit and helps prevent sparking so it’s much safer.


Step 5: Start the mower’s engine

Head to the lawn tractor and turn the mower’s engine on.

It will come on but if it doesn’t, leave the connection intact for a few minutes to allow the mower battery to get some juice before restarting it.

You may not necessarily need to start the car’s engine (The mower doesn’t really draw that much and can turn over while the car is off)

However, if you must, confirm that your mower is off before starting the car as you risk overloading the mower battery once the car comes on.

Side note: The more “flat” your battery has become, the longer you could need to wait before retrying.


Step 6: Give it time to charge

We advise you to at least let it draw some energy from the car battery for about 5 minutes so do not be too quick to disconnect it from the car.


Step 7: Disconnect everything

After the five minutes, your mower battery is, in many instances, loaded enough to power the lawn mower on its own.

It’s now a good time to disconnect the charging setup…..

Detach the black clip first from the mower then from the car and finish with the red ones in the same sequence.

You can now switch off the car but not the mower- drive it around for 30 minutes or thereabout to give the battery ample charge.

Voila! That’s how to charge a lawn mower battery with a car with the help of your inexpensive jump start cables.

How to charge a lawn mower battery with a car- use the car battery direct

Your 12V car battery is  competent enough to crank your mower on its own and is another alternative (you may not have the jumper cables with you).


  • Get the vehicle battery out and place it on the mower somewhere safe (the space inside the mower is quite limited and I doubt you’ll be able to fit it properly inside unless you somewhere invest some room).
  • Connect the two mower battery terminals to the car battery tightly and attempt to turn it over.
  • Here is the thing: Once it’s cranked, your riding mower doesn’t require the battery any more and will keep running even after you remove the car battery.

That’s all!


Charging a lawn mower battery with a car: what to keep in mind

There are a couple of things you should know about charging a lawn mower battery with a vehicle:

· Beware of other problems

There’s always a chance that the mower won’t turn on if the connection is loose or due to other issues such as the mower being low on gas.

Check on these and like problems –the battery could even be long dead- if it totally refuses to start.

· Do not attempt this with a 6 volts battery

As mentioned above, don’t charge 6 volt batteries using the car jump-starting technique as it could kill the battery (use the correct battery charger).

·  Dirty battery posts will make your work more difficult

Remember to clean the battery posts if you notice the white crusty buildup before jump-starting.

Battery corrosion on the terminals and or cables prevents the establishment of a perfect electrical connection.

·  Protect yourself

It’s always wise to wear protective gear such as gloves and glasses before doing any work on batteries.

Also, clean off any powdery stuff that may get on you immediately during the process (use soap and water).


Final word

The best way to avoid battery problems caused by long periods of disuse during the cold months is to ‘winterize’ the battery.

Simply remove the lawn mower battery from the machine and keep it fully charged in storage (a trickle charger works wonderfully).

This ensures that the battery will be ready to power up your lawn mowing machine when the grass needs to be cut in the spring.



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