Can You Jump Start a Lawn Mower (With a Car Battery)

After a long winter storage it is quite common for a lawn mower battery to become flat. This should not be a great deal if you can access a car battery. You can safely jumpstart a riding lawn mower battery with your car battery. Let’s look at how it’s done the right way.

Before you jumpstart your lawn mower battery, you’ll want to be sure that dead battery is the main reasons why your riding lawn mower won’t start. Begin by checking the oil and gas levels before you troubleshoot. Most likely a battery is the problem if you can hear a clicking sound when trying to start the engine.

Next is to make sure that you have a 12-Volt battery. A sticker or stamp on the casing of the battery will indicate the voltage. You can locate your lawn mower battery under-seat; under-drink holder or behind the wheel. You’d also want to be sure that the mower battery is clean and in a good condition.

How to Jump Start a Lawn Mower Battery with a Car Battery

To successfully jump-start a lawn mower, you have to ensure that terminals and poles for both batteries are clean, secure and not damaged. In most cases, a long storage can lead to corrosion on the terminals. A white crusty build-up on the terminals and battery posts can prevent the flow of current as you jumpstart or charge it.

If that is the case, sprinkle some baking soda on the terminals and add a small amount of water. This will neutralize the acid and make it easy to remove the corrosion. Next, use a wire brush to clean the terminals and poles. Wipe the surface dry and apply a coat of petroleum jelly to help protect against corrosion.

Before you start, you’ll also need a quality set of jumping cables. Damaged, worn or dirty cables will can also fail the boosting process. Damaged cables may have broken wires within which cause excessive resistance when power flows. Often, you may notice such cables getting too hot while trying to jump start your lawn mower.

More important, observe safety. You need to have a protective eyewear and leather gloves to protect against shock. Work away from children and in a safe place without flammables nearby.

Jump Starting Steps

  1. Move your vehicle close to the mower or vice versa, turf off the engine and pop the hood to access the battery. Most likely you’ll have to remove a plastic cover from the car battery terminals.
  2. Look out for positive and negative markings on the battery casing. Battery poles are commonly colored red for positive (+) and black for negative (-)
  3. Start by connecting the positive red (+) of the mower battery to the red (+) of the car battery.
  4. Now connect the negative black (-) on the car battery to a ground source on the mower. (Any bare metal on the lawn mower)
  5. Start the lawn mower engine and let it run for about 5 minutes before you remove the jumper cables.
  6. Remove the jumpers in a reverse order starting from the black on the ground source, then from the negative (black) of the car battery, followed by the positive (red) of the car battery and finally from the  positive (red) of the lawn mower battery.

When jump starting, you have to make sure that you are starting your riding lawn mower the right way. Otherwise an open safety sensor may prevent the engine from starting. Also, if your engine does not start at all, then your lawn mower battery is likely dead completely and you have to replace it.

Can you charge a lawn mower battery with a car battery?

Charging a lawn mower battery with another battery will not be effective. Typically, it is not possible to charge a 12V battery with another 12V battery directly. Charging process will not continue once the two batteries attain the save average charge level.

However, you can jumps start a lawn mower with another fully charged 12-volt battery. You may even use the car battery without having to bring the car around. Once the mower has successfully started, the battery should be disconnected so that the mower’s alternator can pick up in keeping it charged.

When to Charge a Lawn Mower Battery

Riding lawn mower engines rely on battery power to start. The battery must be fully charged for this to work. However, you don’t need to charge your mower’s battery routinely, but probably when your battery is unresponsive, or you are planning for a storage or startup.

The idea of jumpstarting a lawnmower battery applies only if you don’t have a working charger. But it is always a good idea to have a recommended modern charger for your lawn mower. You can easily damage your lawn mower battery by using old model or wrong type of a charger.

Most lawn tractors come with a 12-volt battery which also need a charger of that particular ratings. If you happen to have a 6-volt battery, then you should not use a 12-volt charger unless it has a setting you can toggle to match the battery voltage.

Fortunately, modern battery chargers have multiple mode settings, including slow charge, fast charge and jumpstart. There is also an integrated charging timer feature that ensures that you are not overcharging your lawn mower battery.

Final Thought

You risk a dead battery by storing it for longer without charging. Extremely cold temperatures are known to drain batteries. If you did not plan to recharge your battery, you can jumpstart it using a car battery and get right back on track with your mowing schedules.

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