How to charge a lawnmower battery with a car?


Sometimes, you leave your Lawnmower stored for a more extended period, especially during the winter. Or you are not home for some time during the summer holiday season, and the mower is not used. When you finally want to use it and take your Lawnmower out, it will not start. The battery got discharged and got too low. If your Lawnmower uses lead-acid batteries to start the engine, these batteries can slowly discharge. The older the battery gets, the bigger the problem. It means you need to charge the battery to keep your mower going. But charging takes time, or you do not even have a charger at hand. What can you do? Can you jumpstart the mower and leave it running?

How to charge a lawnmower battery with a car:

You can use your car to jumpstart your Lawnmower. But first, make sure that the Lawnmower uses a 12-volt battery. The best is to leave the car running while doing it. Use jump start cables to connect both the + and – from the car battery with the lawnmower battery. Start the Lawnmower, wait a few seconds, and disconnects the jump start cables. Now leave the Lawnmower running for some time to make it charge the battery.

In this article, we will further explain how to jumpstart your mower by using a car if you are in a hurry or do not have a battery charger.

Steps to jumpstart a lawnmower by using a car

You can safely charge your mower’s battery by using another car if you don’t have a battery charger. If you use this method, please check the safety instructions as well. Please make sure that the Lawnmower and the car are both using a 12-volt battery.

● Step 1: Move your car and mower together

After you have made sure that the Lawnmower uses a 12 Vols battery, move your vehicle and mower close enough to connect the charging cables easily. Open the hood of your car (or the back door if the battery is located in the back) and ensure that the lawnmower battery is reachable. For most lawnmower models, the battery is under the seat, and in that case, you can lift the seat. Other models have the battery near the engine in the front, and in that case, you can lift the mower hood.

● Step 2: Clean corrosion

If the lawnmower battery terminals look dirty, clean the first. Cleaning corrosion on the terminals using a battery terminal cleaner can necessary in some cases to make good contact and ensures that it does not lose power.

● Step 3: Connect the cables

 After doing the above steps, now it’s time to connect the battery cables. First make you’re your car is started. Be careful while connecting the battery terminals, and never connect the black jumper cable clamp with the dead battery. There are leads on the car’s battery. One is called the red lead, and the other one is called a black lead. The terminals of the lawnmower battery are connected with these leads. Connect the lawnmower battery’s positive terminal with the red lead and the other end of the red lead with the car’s battery’s positive terminal. Similarly, connect the lawnmower battery’s negative terminal with the black lead and the other end of the black lead to the car’s battery’s negative terminal. Now start your car and give your mower’s battery a few minutes to charge. Keep in mind that when the batteries are connected, don’t do anything messy. In case something happens, quickly disconnect the red lead from the car’s battery and disconnect it from the mower’s battery too. This will be safe.

● Step 4: Start the mower

After connecting the cables, you need to start the mower. After the mower’s battery has charged for a short time (up to a few minutes), start the mower while the car is still running. Your mower will start immediately. If this does not happen, let the mower’s battery charging for another few minutes and try again. If it still does not start, there may be another problem.

● Step 5: Disconnect the cables

If your mower starts, then the next process you will do is disconnect the cables. Be careful while disconnecting the cables. In this step, you will have to remove the cables in reverse order. First of all, disconnect the black lead from the mower’s engine and then disconnect it from the car. Now, it comes to the red leads. Similarly, disconnect the red lead from the mower’s engine and then disconnect it from the car’s engine as well. If you don’t want to start mowing and want to charge the battery fully. Just leave the mower running for another 10 minutes and let the mower’s battery be charged fully.

Safety Precautions

While repairing any machine, you need to take care of the safety precautions as well. You must follow the safety rule before repairing any machinery. This will keep you safe from any incident. Similarly, while charging a mower’s battery from a car’s battery, you need to follow some safety rules as well. While connecting the cables, you need to be very careful and try not to touch any metal, or electricity will flow. Following are some safety precautions you may observe:

  1. Must wear protective gloves and goggles. Your Lawnmower’s battery contains strong acid, and in some rare cases, it can explode while jumpstarting it. There is very little chance that this might happen, but still, you should protect yourself.
  2. Don’t leave the mower’s battery hooked up with the car’s battery. The car’s battery is slightly more potent than the mower’s battery. If you leave it hooked up, the jumpstarting process is over.
  3. Try to stay away from the battery while connecting the cables. A spark may fly when the cables make contact; this may cause an explosion.
  4. Turn off the car engine before starting the mower. If the engine runs the mower’s battery, it will be overloaded by the car’s alternator and cause an explosion. It can damage the batteries as well.

Frequently asked questions

1. If the jumpstarting doesn’t work, what to do?

If the jumpstarting doesn’t work and the Lawnmower dies soon after disconnecting the cables or not starting again when you turn it off, then the mower’s battery may be shot. On average, a lawn mower’s battery lasts for about three years without any charge. If the mower starts for a few minutes and then dies, there may be a problem with the voltage regulator or alternator. You need to check all the voltage and alternator if this happens. You must call a professional to check it or buy a new one.

2. How to keep a mower’s battery from dying?

Some people leave the Lawnmower in the stores for all winters. If the battery is not in use, it starts draining. You will find that your mower’s battery needs to get charged every season, but this is not usual. Some people take their lawn mower’s battery out and leave them in their store. There is another better way. Afloat charger is a device that keeps the battery fully charged when it is left. It is the simplest way. You need to connect the clamps with the battery and leave it connected all winter. It will not let your battery die.

3. Is there any other way to jumpstart a lawnmower?

Some people are scared of jumpstarting their lawn mower’s battery with a car’s battery.  If you are scared too, then some other ways might help you. You can use an extra car battery if you have it. Just hook the mower’s battery with it in the same way as mentioned above. After hooking, try to start the mower. If it works, that’s good for you, but the battery isn’t strong enough if you fail to do it.

On the other hand, there is another way to jumpstart the mower. In this case, you will need to push your mower to a suitable hill. In this method, the clutch is used. Please take it to top the top and set the parking brakes. Turn the ignition on. Press the clutch and shift it to the lowest gear. Press the clutch and release the brake. You will observe that the mower will roll down. When it is at top speed, release the clutch. In this way, the mower will start.

Final remarks

People who use lawnmowers can face the issue of the battery up to once every season. During, winter they leave their lawnmowers in the store, and after winter, when they try to use them, they face battery-dying issues. If you face this issue, don’t get worried. You can jumpstart your mower’s battery with a car’s battery if you don’t have a battery charger. Always keep in mind the safety precautions before doing this. However, we highly recommend you purchase a battery charger as it is the safest of all.

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