You probably don’t give much thought to your lawn mower battery—until it stops working. A healthy, properly charged battery is essential for smooth mowing, and it can save you from those frustrating moments when your mower won’t start. So, what voltage should a new lawn mower battery have?
In this guide, we’ll break down exactly how many volts your lawn mower battery should have, how to test it, why it matters, and most importantly, how you can take care of your battery, so it lasts longer.
How Many Volts Is a Lawn Mower Battery?
When asked, how many volts are in a lawn mower battery, the answer largely depends on whether you’re using a traditional gas-powered mower with an electric start, or a cordless, battery-powered mower:
Gas-Powered Mowers
For gas-powered mowers, 12-volt lead-acid batteries are the industry standard, while some older or smaller models might use 6-volt batteries. This applies to both push mowers and riding mowers equipped with electric start systems. These batteries provide just the right amount of power to start the engine and run any additional electrical components, such as headlights or control systems.
If you’re using a gas-powered mower, it’s a safe bet that you’ll need a 12V battery. A fully charged 12V battery should read between 12.6 and 12.7 volts, while some AGM (Absorbent Glass Mat) batteries can even reach up to 12.8 volts. Anything below this range signals that your battery is not fully charged, which could impact your mower’s ability to start.
Battery-Powered Mowers
Now, how many volts are lawn mower batteries of modern cordless models? Well, electric lawn mowers typically use lithium-ion (Li-ion) batteries, and they come in a wide range of voltages, each tailored to suit different lawn sizes and mowing needs. Here’s a breakdown of common battery voltages and their uses:
- 20V:Ideal for small, lightweight mowers designed for tiny yards or patchy lawns. These are perfect for quick, simple jobs.
- 40V:A step up, 40V mowers are great for medium-sized lawns, typically around 1/4 to 1/2 acre. They strike a good balance between power and portability.
- 56V to 60V:These mowers pack more power, making them ideal for larger lawns or areas with thicker grass. They’re versatile and designed for tougher tasks.
- 80V and Above:These heavy-duty mowers are built for commercial use or very large properties. They deliver exceptional power and extended runtime, handling tough grass and large areas with ease.
How to Test the Voltage of a Lawn Mower Battery?
Now that you understand what volt is a lawn mower battery, let’s talk about testing. Testing the voltage of your lawn mower battery is a simple yet essential task to ensure your mower performs reliably.
Whether your mower has been sitting idle for a while or you’re troubleshooting starting issues, checking the voltage will give you a clear idea of your battery’s condition. Here's a step-by-step guide on how to test the voltage of a 12V lawn mower battery:
What You’ll Need:
A multimeter (preferably digital for easier reading).
Safety gloves (optional, but recommended).
1. Turn Off the Mower
Before starting, make sure the lawn mower is completely turned off, and the engine has cooled down. Let the mower sit unused for at least one hour. Testing the battery immediately after use can give false readings since the battery might still hold a temporary charge.
2. Locate the Battery
Open the battery compartment of your mower, typically found under the seat for riding mowers or near the engine for push mowers. Identify the battery terminals — the positive terminal is marked with a “+” sign and the negative terminal with a “-” sign.
3. Inspect and Clean the Terminals
Examine the battery terminals for dirt, debris, or corrosion. If you spot buildup, use a wire brush or cloth to clean the terminals. Clean terminals ensure proper contact for an accurate voltage measurement.
4. Set Up the Multimeter
Turn your multimeter on and set it to measure DC voltage (denoted by “DCV”). Ensure the voltage range is set to 20V or higher, as a 12V battery will fall within this range.
5. Connect the Multimeter Probes
- Attach the red probeof the multimeter to the positive terminal marked with a “+”
- Attach the black probeto the negative terminal marked with a “-”
Make sure the probes are securely connected to avoid interference with the reading.
6. Check the Voltage Reading
Look at the multimeter display to check how many volts is lawn mower battery. Here’s how to interpret the results for a 12V lawn mower battery:
- 6–12.7 volts:Fully charged and ready for use. This is the ideal voltage range for consistent performance.
- 4 volts:About half-charged. While your mower might still start, it’s a good idea to recharge the battery soon to avoid issues.
- 2 volts: Considered flat. Although some mowers might still start at this voltage, it’s unlikely and unreliable. Operating your mower at this level risks sudden failure.
- Below 12 volts: At this point, the battery is no longer functional for starting your mower and may need recharging or replacement
7. Take Action Based on the Results
If the voltage is below 12.6 volts, recharge the battery using a compatible battery charger. For readings consistently below 12 volts, consider replacing the battery to avoid further issues with your mower.
Why Is Battery Voltage Important for Your Lawn Mower?
Now that you know how many volts of a lawn mower battery is considered healthy, you might wonder why it’s such a big deal. The truth is the right voltage keeps your mower running efficiently and protects it from unnecessary wear and tear. Here’s why it matters:
- Reliable Starting: Correct voltage ensures your mower’s engine starts smoothly and powers the cutting blades effectively. Low voltage (like below 12.2 volts) can result in starting issues or complete failure.
- Powers Electrical Components:The battery powers additional features like headlights or safety controls. Low voltage can cause these systems to malfunction, impacting usability and safety.
- Prevents Battery Damage:Operating a battery at low voltage leads to deep discharge and sulphation, which reduces battery capacity and lifespan. Keeping the battery properly charged ensures durability.
- Optimizes Electric Mower Performance: For cordless mowers, voltage directly impacts power and runtime. Higher-voltage batteries handle tougher grass and larger lawns better, while low voltage can lead to power loss or shutdowns.
- Supports the Charging System:In gas mowers, proper voltage prevents overburdening the alternator or charging system, ensuring efficient operation and reducing wear.
Tips to Maintain and Extend the Life of Your Lawn Mower Battery
As you can see, keeping your lawn mower battery in good condition is essential for reliable performance and long-term use. Here are some simple tips to help you maintain and extend its life:
- Charge Regularly: Recharge your battery after each use, especially during heavy mowing seasons. Avoid letting it drop below 12 volts, as deep discharge can damage the battery.
- Store Properly:During the off-season, store your battery in a cool, dry place away from extreme temperatures. Use a trickle charger to maintain its charge while in storage.
- Clean the Terminals: Regularly inspect and clean the battery terminals to remove dirt, corrosion, or debris. Use a wire brush and apply a terminal protector to prevent future buildup.
- Check Voltage Often:Use a multimeter to check the voltage periodically. A fully charged 12V battery should read 12.6–12.7 volts. Recharge as needed to maintain optimal levels.
- Avoid Overcharging:Overcharging can cause overheating and shorten the battery’s lifespan. Use a charger with an automatic shutoff to prevent this issue.
- Inspect for Damage: Look for cracks, leaks, or swelling on the battery case. Replace the battery immediately if you notice any damage.
Conclusion
Knowing what voltage a new lawn mower battery should have is just the beginning of good lawn mower maintenance. As we’ve learned, most gas-powered push or riding mowers use 12-volt batteries, while modern electric mowers can vary more widely in battery voltages. By staying proactive, regularly testing your battery’s voltage, and following the best practices for maintenance, you can avoid unexpected breakdowns and ensure that your lawn mower remains a reliable tool for years to come.
FAQs
How to tell if a lawn mower battery is bad?
If your mower struggles to start, or the battery reads below 12 volts on a multimeter even after charging, it may be bad. Signs of a bad battery include corrosion, leaking, or consistently low performance.
What should a 12 volt lawn mower battery read?
A healthy 12-volt battery should read between 12.6 and 12.7 volts when fully charged. If it’s below 12 volts, the battery likely needs recharging or replacement.
Can you charge a lawn mower battery with a 12 volt charger?
Yes, you can charge a 12-volt lawn mower battery with a 12-volt charger. Make sure to use a charger designed for small batteries and monitor the process to avoid overcharging.
Should lawn mower battery be 12V or 6V?
Most modern gas-powered lawn mowers use 12-volt batteries, which provide more power and reliability. However, some older models or smaller mowers might use 6-volt batteries, so check your mower’s manual.
