It is not unusual to find a lawn tractor battery dead at the beginning of the mowing season in the spring. This is because the battery sits without actively charging and recharging. The battery will discharge more quickly if the battery cables are left hooked to the battery. Part of a good winterization program for a lawn tractor is to disconnect, remove and store the battery in a garage. If you do find a dead lawn tractor battery, it can be recharged with the right equipment.
The Right Equipment
When a charged battery is installed in a lawn tractor, its power is being used and replenished as the lawn tractor engine runs via an alternator-like charging unit. Otherwise, the battery would die quickly and the lawn tractor would shut down and not start up again until the battery is recharged, reinstalled and reconnected to the lawn tractor's electrical system. When the battery is dead, it must be recharged by hooking it up to a battery charger. The brand or size of battery charger does not matter as long as the battery's specifications fall within the charging capabilities of the battery charger.
Warning: Lawn tractor batteries are smaller than car batteries, so it would not be safe to jump-start a lawn tractor battery with a car battery. The lawn tractor battery could explode or at least emit harmful vapors that may ignite, causing an explosion. Do not charge batteries in an enclosed area. Provide adequate ventilation while charging so vapors will not accumulate to dangerous levels.
Charging Lawn Tractor Batteries
Many battery chargers have a variable charge rate feature that allows the charger to charge batteries of varying sizes. For example, charge rate capabilities for a given battery charger may be indicated by a 2-, 10- or a 15-amp charging rate. Because lawn tractor batteries are small, they should be charged at the 2-amp charge rate, or an equivalent recommended charge rate for the battery charger you are using. Charging the battery using a higher charge rate amperage may damage the battery. Remove the battery from the lawn tractor and place the battery in a well-ventilated area. Connect the charger cables to the battery before plugging the battery charger into a wall outlet. Connect the black wire clamp to the negative (-) battery terminal and the red wire clamp to the positive (+) battery terminal. After plugging the battery charger into the wall, set the charge rate and allow the battery charger to work its magic. Electronic battery chargers alert their users when the charging process is complete, using an alarm or a beeping sound.
Disconnecting the Battery Charger
Caution should be employed when disconnecting a battery charger. As has been touched earlier, toxic and combustible gases will accumulate around the battery while it is charging. Use a piece of cardboard to blow the gases away from the battery to avoid an explosion. Unplug the battery charger from the wall outlet. Disconnect the negative (-) terminal clamp first, followed by the positive (+) terminal clamp. Do so at arm's length with your face away from the battery. Reinstall and reconnect the battery to the lawn tractor and fire up the engine.