A lawn mower battery may be needed for two very different reasons. A majority of lawn mowers are powered by small internal combustion engines. If these lawn mowers use batteries, they use them in the same fashion that automobiles use batteries, for starting power and to run a few small devices. Rechargeable electric lawnmowers have gained in popularity in recent years, and use batteries as their sole source of power. When choosing a battery for a lawn mower, it is critical to choose a battery appropriate for the type of mower that it will be used in.
The stereotypical gasoline-powered lawnmower has a simple cord-powered starter. Larger mowers, and almost all riding mowers, however, rely on electric starters. These starters need a lead-acid lawn mower battery that delivers a great deal of power in a short period of time. Most of these batteries are twelve volts, but some models use smaller six volt batteries. Matching the size and voltage requirements of a lawn mower battery is critical, and the old battery or the owner's manual should be consulted. Lithium-ion and nickel-metal hydride batteries should never be substituted for lead-acid batteries.
When comparing different lead-acid batteries, the most important factors to consider are probably the warranty on the battery and the price. The ability of a lawn mower battery to withstand cold-weather conditions need only be considered if the riding lawnmower will also be used to blow snow or plow. Mowers that see no winter service can make do with batteries that are not designed to start engines in the cold.
Electrically-powered lawnmowers demand different things from it's lawn mower battery. A battery that will power a mower needs to have a large storage capacity and be able to handle frequent charging. In some cases, electric mowers use lead-acid batteries, not least of all because they are cheap. When shopping for such a battery, look for deep-cycle batteries. These batteries, unlike starter batteries, deliver less peak current but can provide a steady current for a longer period of time. They are also much more durable.
More advanced electric mowers may use lithium-ion or nickel-metal hydride batteries. These batteries excel at delivering power for a longer period of time. Unlike lead-acid batteries, however, they are not generally produced in generic shapes and sizes. This means that when shopping for this type of lawn mower battery, simply order the appropriate battery from the manufacturer.