How To Safely Jump-Start A Lawn Mower Battery With Your Car (But Should You?)

Whether you have a push mower, a riding lawn mower, or a lawn tractor, many of their engines are powered by batteries. And the batteries are similar to automobile batteries except they are smaller, cost less, and have fewer amps. But there is another similarity. It doesn't matter if your lawn mower is from Home Depot or Lowe's — you can drain the battery by leaving the ignition on or not using the machine for a long period of time.

Batteries don't last forever. They wear out and run down, just like your vehicle's battery. If the charge from your mower's battery is dead after being unused for many months, and your mower and car have the same voltage (12V is most common) — you can try jump-starting your lawn mower battery before spending money on a new replacement.

There are a few ways you can tell if the battery just needs a jump start or it needs replacing. If the battery doesn't work even after attempting to jump-start it, more than likely it will need to be replaced. If the battery has to be jump-started again after each use, that is another indication it has gotten too old and you'll need a new one. Dirty terminals can prevent the battery from working properly, so if you notice corrosion, clean the terminals before you jump-start the battery. When the sides of the battery case are bulging or swollen, the battery is damaged and should not be jump-started. This sign means an immediate replacement is necessary as it could explode and cause serious injury.

Keep a few safety tips in mind when jump-starting your lawn mower to ensure a safe and positive outcome. Make sure the mower is on a flat surface; a driveway will work fine. Make sure your vehicle and the mower are turned off. Connect the red clamp onto your car battery's positive terminal and the opposite red clamp to the mower's positive terminal. 

Next, connect the black terminal to the car's negative terminal and connect the opposite black clamp to a piece of metal on the mower's frame. Now you can start your car and let it run for five or 10 minutes — but do not start the mower during this time or whenever the car is connected to it and running. Before trying to start the mower, shut off the car and then see if the engine turns over. If it starts, you're good to go and can remove the cables the same way you do when jump-starting a car.

Once you have the mower running again, whether you successfully jump-started the battery or had to by a new one, keep up with the battery maintenance by keeping the terminals clean. You should also start your mower periodically, especially during the winter months, and store it properly by removing the battery in winter. Other types of maintenance are just as important, such as cleaning and maintaining your mower's air filter and blades. With proper maintenance, your lawn mower can last a long time!