Can You Charge a Lawn Mower Battery With a Car Battery Charger?

Charging a lawn mower battery using a car battery charger is possible. However, to accomplish this task correctly, there are a few considerations that you must keep in mind to ensure it will function well while assuring your safety. Read on to find out the entire process.

John Deere Battery Size Chart

Battery Size Cold Cranking Amps (CCA) Reserve Capacity (minutes) Group Size
U1 55 40 1
U1-H 85 60 1-H
U1-L 30 20 1-L
U1-R 45 30 1-R
U2 70 45 2
U2-H 105 65 2-H
U2-L 35 25 2-L
U2-R 50 35 2-R
U3 85 60 3
U3-H 125 80 3-H
U3-L 40 30 3-L
U3-R 65 45 3-R
U4 95 70 4
U4-H 135 90 4-H
U4-L 45 35 4-L
U4-R 75 50 4-R
U5 105 75 5
U5-H 145 100 5-H
U5-L 50 40 5-L
U5-R 85 60 5-R
U6 115 85 6
U6-H 155 110 6-H
U6-L 55 45 6-L
U6-R 95 70 6-R
U7 125 95 7
U7-H 165 120 7-H
U7-L 60 50 7-L
U7-R 105 75 7-R
U8 135 105 8
U8-H 175 130 8-H
U8-L 65 55 8-L
U8-R 115 85 8-R
U9 145 115 9
U9-H 185 140 9-H
U9-L 70 60 9-L
U9-R 125 95 9-R

How to Charge a Lawn Mower Battery Without a Charger?

Follow these steps in charging lawn mower battery without a charger:

  1. Put on protective gear for your safety, including safety gloves, protective clothing, and eyewear protection.
  2. Choose a place to park your vehicle with plenty of space and comfort, and switch off the engine.
  3. Clear out the storage areas of the lawn mower and the car batteries of any cords, wires, and other trash.
  4. Take off the battery covers from the car and the mowers.
  5. Remove the battery’s connector to prevent electrocution.
  6. Connect one end of the red lead to the positive terminal on the battery that powers your lawn mower and the other to the positive terminal on the battery that powers your automobile; any exposed metal on the lawn mower should be connected to the black lead.
  7. Check the battery’s voltage and ensure it has the same voltage as the battery in the car. Failure to do so will cause a battery explosion when you jump-start the mower. Typically, lawnmowers require 12-volt batteries.
  8. Finally, test the mower.

How Can I Charge a Lawn Mower Battery with a Car Charger?

If you have a new or old car battery charger, you can use it to charge your lawn mower battery by following the simple process below.

Step 1: Unplug the Charger

You should disconnect the car battery charger from its outlet so that there are no safety issues while connecting the charger to the mower. Remember to wear protective equipment like gloves and glasses to stay safe.

Step 2: Locate the Mower’s Battery

You will need to figure out where the lawn mower’s battery is. If you are unsure about the location, you can seek information from the user guide that came along with your lawn mower.

Step 3: Connect the Charger

Attach the red cable to the positive end of the battery and then the black cord to the opposing end to connect the car battery charger to the mower’s battery.

Step 4: Confirm the Voltage

Ensure that the charger’s voltage matches the lawn mower’s battery. Generally, this will be 12 volts. This will help you maintain efficiency as well as safety.

Step 5: Plug the Charger In

Once you have successfully completed the steps mentioned above, you can plug your car battery charger back into the power or electrical outlet and turn on the switch to the outlet.

Step 6: Let It Charge

If you have a 10-ampere charger, you can expect a charging and waiting period of an hour until your lawn mower’s battery is fully charged. If the output is lower than ten amps, it might ultimately increase the time it takes to charge the battery by several hours. It might even take longer if your battery is dead.

Step 7: Disconnect the Charger

You can then disconnect the charger from the battery by removing the black cable first, followed by the red cable. This will conclude your process, following which you can start using your lawn mower again.

It would be a good idea to test out the mower first for a minute before using it fully. It would be best to let it run for a specific time to confirm that it is working well.

Frequently Asked Questions

Can You Charge a Lawn Mower Battery with a 12-volt Charger?

Yes, you can charge a lawn mower battery with a 12-volt charger. The newer lawn mower models tend to have a voltage capacity of 12 volts, making a 12-volt charger ideal for this process.

Can You Recharge a Dead Lawn Mower Battery?

You can surely recharge a dead lawn mower battery by following the abovementioned method. But since the lawn mower battery was dead, it might take a bit longer to recharge fully before you can use it again.

Are There Any Other Ways to Charge a Lawn Mower Battery Using a Car?

Yes! It requires you to connect the battery to your car’s battery directly. To do this, you should place the mower and car close together. Then attach the red and black cables to the batteries (the red ones to the positive terminals and the black ones to the negative). Lastly, please test it out by turning on your lawn mower. If it doesn’t turn on, try to wait a while before testing it out again. After that, you can disconnect the cables once it starts working. Ensure to remove the black ones first, followed by the red ones.

Using a trickle charger to make the charge last longer with a steady trickly can also be a good idea. You can also buy a portable jump starter or a screwdriver to get the engine going.

If nothing works above, you can invest in a battery charger for lawn mower or ask a professional to fix it. You can search online; just typer lawn mower battery charger Walmart on the search bar and it will show you the options to choose from.

When Is the Best Time to Charge a Lawn Mower Battery?

Generally, it would be best if you charged a lawn mower battery before keeping it for storage during winter. This will ensure the mower does not run out of too much battery during the cold season.

You should also do this right after taking the mower out of storage. If your lawn mower runs out of battery or dies, you need to charge it again.

If you know how long to charge a lawn mower battery, you can keep it working for years to come. A properly charged lawn mower battery will give you the power you need to start your engine, even on a cold day.

Can You Charge a Lawn Mower with a 6-volt Battery Charger?

Newer lawn mower models (usually after 1980) come with a voltage setting of 12 volts. So, it would be better for you to use a 12-volt charger and not a 6-volt charger.

However, you should check the voltage setting if you own an older model’s functional lawn mower. If it says 6 volts, you can safely use a 6-volt battery charger.

Are There Any Ways to Make Your Lawn Mower Battery Last Longer?

Yes, there are several ways that you can make good use of to make your lawn mower battery last longer. Some of these include:

  • Use a trickle charger to draw out the battery without overcharging concerns. It will also ensure that the charge goes on for a long time.
  • Clean up the batteries to prevent a build-up of rust or corrosion. You should do this regularly to prevent issues.
  • Regularly servicing your lawn mower to fix minor problems.
  • Ensuring that you maintain similar voltage settings at all times while charging.
  • Use your mower periodically or keep it in good condition while storing it in the winter.


Using a car battery charger to charge a lawn mower battery is not a daunting task to do. However, you must follow the steps thoughtfully and attentively, as improper execution may result in vehicle damage or an accident. Additionally, you must ensure that the battery voltage is appropriate for your lawn mower—failure to do so results in overheating or a decrease in charging performance. More importantly, it is crucial to wear safety and protective gear or equipment before performing such mechanical operations.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.