By David Dritsas
Copyright popularmechanics
Cordless, battery-powered lawn mowers have become strong competitors to their gas-powered counterparts, appreciated for their quiet and emission-free operation. Since there’s no oil, filter, or gas to worry about, people find them easier to maintain, too. However, that doesn’t mean there aren’t best practices for keeping them in good shape — especially their power source. Proper care of rechargeable batteries is essential for maintaining the performance of an electric lawn mower.The average lifespan of a rechargeable lawn mower battery is around three years. However, some can last as long as five (or 300 to 500 charge cycles), depending on how frequently they get used (some brands’ batteries can be used across their cordless power tool line) and how well you take care of them. Based on our research, consultation with different manufacturers’ recommendations, and years of experience reviewing lawn mowers, we compiled a list of best practices for maintaining your rechargeable mower batteries to achieve optimal performance and longevity.What Type of Batteries Do Electric Lawn Mowers Use?Rechargeable lithium-ion batteries most commonly power cordless electric lawn mowers. In push mowers, they’re usually removable, but in some riding mowers and zero-turn mowers, they are built-in. They can be removed and placed in a charger, or recharged using a cable connection (in the case of built-in batteries). These batteries are rated by their voltage (volts) and capacity (amp-hours). Capacity correlates to the size of a gas tank in a fuel-powered mower. Their voltage must match the voltage (V) of the mower’s electrical system, but the amp-hours (Ah) can vary. For example, this mower from Ego Power+ comes with two 56-volt, 6-Ah batteries, but can also run on 56-volt 10-Ah or 7.5-Ah batteries, as well. The higher the capacity, the longer the runtime within the same voltage.Manufacturers design their batteries with a variety of proprietary features, such as thermal and overcharge protection, power level monitoring, and more. They also may have slightly different guidelines than the general ones we list below for the care of their specific batteries, so always read those, as well.Tips For the Proper Care of Electric Lawn Mower BatteriesDon’t let the battery run until it’s dead. Lithium-ion batteries can become damaged if you consistently run them until they are fully discharged. Most battery companies recommend you stop to recharge the battery once it hits 20-percent or when you start to feel the engine power decrease.Avoid fast-charging features. Some companies offer a higher-voltage charge setting that will juice up the battery in much less time than a normal charge. While handy in a pinch, these should be avoided, as a higher voltage input reduces the battery life if used too often. If you’re not in a rush, always choose the lower voltage charging option.Do not leave batteries in the mower or in the charger. Leaving removable batteries in an electric mower can cause a slow drain, cutting down on your runtime the next time you need to cut the grass, so it’s best to remove them between uses.The same goes for fully charged batteries and chargers. While most chargers feature overcharge protection (meaning the charger stops delivering voltage when charged), most manufacturers still recommend removing it from the charger to avoid accidental damage and general electrical safety.Store (and charge) in a cool, dark place. One of the biggest enemies of a rechargeable battery is extreme temperature, especially high heat. This can promote degradation within the battery, and is worsened if you choose to charge the battery in high heat or direct sunlight. Conversely, extreme cold can also be detrimental.Electric mower companies list their recommended temperature range for charging and discharging their batteries, but they can vary, so always follow their specific guidance. For example, some companies suggest storing batteries in a location that’s between 50 and 80 degrees Fahrenheit, but we’ve seen some with wider recommended ranges between 40 and 105 degrees F.It’s not hard to meet these conditions. Most garages and basements are ideal, but be careful of sheds; they can get hot or cold in extreme weather, have high humidity, and may be susceptible to water leaks from worn roofs. For riding mowers with built-in batteries, try to park them in a garage or at least a covered area.Don’t charge a hot battery. Sometimes, after a long mowing session, your battery may be warm or hot to the touch from operation. Immediately charging a hot battery can have the same negative impact as charging it in a hot environment. It’s better to let the battery cool down first. This can take up to two hours, depending on how hot the battery is and the ambient temperature of the storage area.Keep the batteries clean. Since electric lawn mowers house their batteries in an enclosed compartment, this helps keep them protected from caked-on grass clippings and the inevitable debris that collects on the mower. But if they do get dirty, clean them off with a dry or slightly damp cloth. If the terminals are exposed or have any build-up or corrosion on them, you can use a little rubbing alcohol to remove it or a bit of white vinegar, followed by a quick wipe of rubbing alcohol afterward to remove any residue.Keep away from metal objects and liquids. When storing your batteries, keep them separate from any liquids or chemicals. A rechargeable battery pack is well-sealed, but if it were to drop into a bucket of water, it could be damaged.If metal comes into contact with both terminals on the rechargeable battery, this could cause a spark, which in turn could cause a fire hazard. When storing batteries, place them in a cabinet or shelf that is free of metal tools, wires, or magnets.How to Store Electric Mower Batteries for the WinterIf you’re storing your mower over the winter months (or for any extended period of time, remove your mower batteries, charge them to between 40- and 60 percent, and then store them in a cool, dry, and dark place as described above. A lithium-ion battery will lose some of its charge over time, so it’s a good idea to check it every two months or so. If the levels are close to 20 percent or lower, partially recharge the battery again.Some companies offer batteries with a hibernation (or sleep) mode after the power level dips to a certain threshold or isn’t used for a period of time. For example, for the brand Ego Power+, the hibernation mode is activated if the battery is not used for more than one month. It will then deplete itself to 30% and enter a sleep mode. Batteries can be “woken” when placed back into the charger.For riding mowers that have built-in batteries you cannot remove, the temperature tolerance range may be wider if the compartment is protected from the elements. For example, a range of -4 degrees to 113 degrees F. Even so, storing it in a garage or covered area is still preferable. If you do not plan to use your mower or batteries for six months or more, it’s also a good idea to run the mower for a bit to keep it in good working condition.FAQ Electric Lawn Mowers We’ve Tested And Reviewed
