If you store your motorcycle over the winter months, you can do a few things to be sure it will start in spring.
Whether you have a heated garage or not, you should take your battery out of the motorcycle or disconnect the negative cable, so the bike accessories don’t continue to drain the battery.
Check your battery posts and cables for corrosion. You should clean any corrosion with a wire brush, water and baking soda. Coat the posts and ring terminals with suitable protection like silicone grease.
If you have a multimeter, set it on the DC scale at 20 volts. Your meter may have clips or probes for positive and negative. Place the positive on the positive post of the battery and the negative on the negative post. A fully charged 12-volt battery should register between 12.5 and 13.2 volts. If your battery has less than that, it should be placed on a battery charger. Do not use a battery tender to charge a low battery. Tenders are designed to maintain a full charge in your battery, not to charge a battery. Once a full charge is achieved, you can place your tender on the battery. While you have your multimeter handy, turn on your ignition switch and have someone activate your starter button. If the draw on the battery drops the voltage to below 10 volts, you should consider replacing the battery.
If you have the traditional lead-acid battery, you should check the fluid level monthly and add distilled water only to the fill line or to just above the lead plates. When charging, remove the fill caps and charge in a well-ventilated area. Charging causes the release of hydrogen sulfide which is flammable and toxic.
If you use the sealed type or gel battery, check the battery occasionally for cracks from vibration. Often called maintenance- free, these batteries still need to be checked for voltage and placed on a charger to attain a full charge or a battery tender to maintain a near-full charge. There is some danger associated with handling or charging batteries, so always wear gloves and eye protection. Use only chargers designed for motorcycles. Car chargers have a higher amp rating and could damage your battery. Motorcycle batteries are rated at 20 amps and you should not charge at a rate higher than one-tenth of that rating, meaning you should use a 2-amp system.
Remember, trickle chargers are manual systems and must be monitored because they will continue to charge even when a full-charge is achieved. Smart chargers will turn off when a full-charge is reached and are a safer choice. Smart or float chargers also have a desulfation mode which alternates current to knock sulfur off the lead plates. Sulfur on the plates inhibits current flow. Trickle chargers do not have this function.
Several Lithium Ion motorcycle batteries are on the market and have advantages over the lead-acid style but may not be best for your bike. Lithium batteries are smaller than the traditional lead-acid battery, so choosing the right one to fit your battery box is important. These batteries often come with padding to help with fitment and reduce vibration. A definite advantage is they are much lighter than regular batteries. They also have a much slower self-discharge rate and can sit for months without a charge, if disconnected from the motorcycle.
The disadvantages of lithium batteries are the higher cost, and they may not function as well as traditional batteries in cold temperatures. You will need a specific charger or tender to use with lithium batteries to avoid overcharging the battery.
With some proper care during the riding months and proper storage in the winter, you should expect at least two years of service from your battery and more.