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Can a Dead Lawn Mower Battery Be Recharged?

Power - by Bryan Veldboom - updated on 6/28/2023

Using a charger to charge a lawn mower battery

Are you having a hard time starting your riding lawn mower after the winter? It could be due to a dead battery. Batteries Plus is your headquarters for lawn mower batteries. We offer free lawn mower battery testing and carry the best selection of replacement riding lawn mower batteries. But before we get to that, let's go through a few tips to help see if your current battery can be saved.

How Do You Pick a Lawn Mower Battery Charger?

If you have a dead battery on your hands, the first thing you're going to want to do is recharge it. If you don't already have a battery charger, here are some things to keep in mind when choosing one.

  • Make sure the battery charger you select matches the voltage and chemistry of your lawn mower battery.
  • Most riding mowers run off of a 12 volt flooded lead acid battery, although some feature a 6 volt battery instead.
  • The X2Power 0.8 Amp Charger, 1.5 Amp Charger and 3.8 Amp Charger are all perfect for riding mowers.
  • The amperage of the charger will determine how quickly the battery will be recharged.

How Do You Charge a Dead Lawn Mower Battery?

It's important to remember that lead acid batteries vent hydrogen and oxygen gas when charged, so be sure to charge your battery in a well-ventilated area free of any sparks or open flames. Then, follow these steps:

  1. Wear Safety Gear - This includes acid-resistant eye protection, safety gloves and, ideally, a pair of safety shoes and an acid-resistant lab coat or apron.
  2. Locate the Battery - For most riding lawn mowers, the battery will be located under the seat.
  3. Connect the Charging Cables - Connect the red cable to the positive battery terminal and the black cable to the negative battery terminal.
  4. Plug in the Charger - Plug the charger into a wall outlet
  5. Set the Charger's Levels - If your charger has adjustable settings, make sure you set it to the proper battery chemistry (in this case, lead acid), voltage (most likely 12V) and amps (10 or less) for your battery.
  6. Disconnect the Charger Once Completed - The charger's amp level determines how quickly the battery will charge. A 10-amp charger will take about an hour to charge the battery. Smaller amp levels will take longer.

Can You Jump Start a Riding Mower with a Car?

If regular charging doesn't work, you can attempt to jump start the battery. While it's technically possible to jump start a riding mower using a car, it's not the best choice. Lawn mower batteries are typically more difficult to access than car batteries. This introduces a number of safety issues when trying to attach live jumper cables to a difficult-to-reach mower battery.

A portable jump pack is a much better option. It eliminates the possibility of overloading your battery and is much safer than using live jumper cables. The NOCO GB20 Genius Boost Sport provides up to 20 jump starts on a single charge and can also be used on cars, motorcycles and ATVs.

Can You Use a Jump Pack on a Lawn Mower?

Follow these instructions to jump your lawn mower using a jump pack:

  1. When jumping a battery, always wear safety goggles and protective gloves.
  2. Set your jump pack to the correct voltage setting (6 volt or 12 volt, depending on your mower's battery).
  3. Be sure that the jump pack is turned off before making any connections.
  4. Attach the positive clip (red) to the positive battery terminal.
  5. Attach the negative clip (black) to an unpainted metal surface of your mower.
  6. Turn on the jump pack.
  7. Start the mower.
  8. If the mower won't start, wait a few minutes then try again.
  9. Once the motor starts, disconnect the negative black clip first, followed by the positive red clip.
  10. Be sure to drive the mower for around 20 minutes to give the alternator enough time to charge the battery back up.

What Kills a Lawn Mower Battery?

If both regular charging and jump starting fail, there are several possibilities.

  • Your battery could simply be too old. Riding lawn mower batteries typically last between three and five years.
  • Your battery is suffering from sulfation.
  • Your battery could also be suffering from corrosion.

What is the Difference Between Battery Sulfation and Corrosion?

Sulfation - refers to the formation of hard lead sulfate crystals on the battery. This occurs on batteries that have sat for too long in a discharged state and will kill a battery prematurely if not caught soon enough.

Corrosion - a buildup of colorful material that appears on the battery's terminals. This buildup harms a battery's performance by limiting the amount of power that can travel from the battery to the engine and from the charging system back into the battery. For more information, read our blog "What Causes Battery Sulfation and Corrosion?"

Can Battery Sulfation Be Reversed?

Sulfation can be reversed, but only if it's detected quickly enough. After a certain point, the sulfation becomes permanent and the battery will need to be replaced. The X2Power 3.8 Amp Charger has a Recovery mode designed to charge sulfated batteries.

Since sulfation is difficult to detect in time, it's easier to prevent it from happening in the first place. A lawn mower battery will hold a charge for about three to four weeks. If your riding mower will be idle for longer than that, you should maintain its charge using a battery charger.

How Do You Clean Corrosion off Battery Terminals?

  • Be sure to wear proper safety gear, including acid-resistant rubber or nitrile gloves, eye protection and long sleeves.
  • Make certain that your lawn mower's engine is turned off and completely cool before interacting with the battery.
  • Disconnect the battery cables. It's important to disconnect the negative battery cable first, then disconnect the positive battery cable.
  • Create a mixture of one tablespoon of baking soda and one cup of distilled water and apply it to the corroded areas of the battery's terminals.
  • Scrub the terminals using a wire battery terminal brush.
  • Once you are finished cleaning them, wipe off the terminals using a rag or lint-free cloth.
  • Let the battery dry completely before reconnecting the battery cables. Connect the positive cable first, then the negative one.

Learn More in the Batteries Plus Blog

Looking for more information about lawn mower battery care? Our blog has plenty of useful articles, including "How Do I Know What Kind of Lawn Mower Battery I Need?" and "How to Get the Most out of Your Lawn Mower Battery." Or, stop into your nearest Batteries Plus location and have your questions answered by one of our experts in person.

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