|Photo courtesy of BMW|
When you leave a motorcycle sitting long enough without turning on the engine, the battery will lose its charge, just like in a car. If you don't want to deal with a dead battery and you aren't riding your motorcycle regularly, like when winter hits, you can still keep it ready to go at a moment's notice by charging the battery periodically.
When handling a motorcycle battery, you should wear protective gloves and goggles. The fluids that are contained in the battery can be extremely acidic and toxic. If you were to drop or otherwise damage the battery, having those fluids come into contact with your skin, eyes, or any other part of your exposed body could be painful and leave permanent scarring.
Always work in an area that is properly ventilated. There might be fumes coming from the battery, so it is better to be safe than run the risk of inhaling something harmful. Before you can charge the battery, you must remove it from the motorcycle. Use a pair of pliers to loosen the connections that hold the battery in your bike. With the battery removed, place it on a sturdy and flat surface, like the floor or on a work bench. Before continuing, check the battery connections for any corrosion or damage. You can clean them with a wire brush. If you do find damage, you must replace your battery to avoid personal injury or damage to your motorcycle.
Pry off the chamber caps and fill the cells with deionized water. Using any other type of water can harm your battery by introducing other chemicals. Connect the cables from the charger to the battery. Match up the positive cable to the positive terminal, and the negative cable to the negative terminal.
With the connections established, plug the charger into an electrical outlet. The amount of time it will take for the charger to replenish the battery depends on the battery, how depleted it is, and the type of charger you are using. Many times it will take all night to charge a battery, especially if it was fully depleted.
Once the battery charger lights indicate that a full charge has been reached, turn the charger off and disconnect the cables. Connect the battery to the motorcycle just as it was before you removed it.
Because charging a depleted motorcycle battery is a pretty lengthy process, it's best to give yourself plenty of time to perform the task. Many motorcycle owners regularly charge up their battery as a way to avoid a surprise when they need to use their bike, which is a smart practice you should consider.