Your Motorcycle Battery Basics

New high-tech motorcycle batteries are still lead-acid batteries just like always. So 'maintenance-free' actually means 'reduced maintenance.' Instead of having the plates bathed in cells of acid, the modern motorcycle battery is sealed and the plates are surrounded by AGM (Absorbed Glass Matt), which carries the electrolyte. You don't have to add fluid, and the battery can be mounted at almost any angle, short of upside-down. They still have to be changed, and they still can be destroyed by neglect.

A fully charged motorcycle battery has a very long shell life. When the key is off (assuming there is a key or an on/off-switch), there are a whole bunch of ions with tooo many electrons bunched up the negative side. Those electrons want to get to the positive side where there are too many protons. A high-quality motorcycle battery won't let them do that, and the status quo can last a long time. On the atoms have balanced numbers of electrons and protons, you no longer have a battery. You have a paperweight full of harmful acid. And it might not ever become a battery again. Bottom line: Charge your motorcycle battery before you storage it.

When a motorcycle battery is depleted, deposits form that more or less insulate the plates from the surrounding electrolyte. Sometimes a strong, short change can eliminate those deposits, but more often than not, this will only overheat and damage the battery.

Anyway, if the battery does not accept a charge, you're out of luck.

A fully charged 12-volt motorcycle battery should read about 12.8 volt if it's low, it should be charged at ten percent of its amp-hour rating. An 11 amp-hour battery can safely be charged at 1.1 amps. It can usually be charged overnight. High-amp automotive quick chargers are generally a bad idea for small motorcycle batteries because they will generate too much heat, causing the case to melt and the plates to distort.

That can't happen with a 'smart' charger, which turns itself off when the battery is charged. In fact, with a smart charger you can leave your battery on the charger for months without bad results.

Some motorcycle batteries are sold full charged and sealed, while some are sold in a combo pack, which means the battery is dry and you add electrolyte yourself and seal the battery after purchase. In the latter case, you should charge the battery immediately after adding the electrolyte. The advantage is that there's no danger that it has gone bad in the dealer's inventory.

When a motorcycle battery is sold fully sealed and charged, chances are it's ready to go. You should have your dealer check the battery with a volt meter before you leave, just to be sure. If it's lower than 2.8 volts, have him charge it before you walk out the door.

In these times, manufacturers know that the machine might sit on the dealer's showroom for a long time. They don't want a dead battery to wreck a sale, so the original battery is usually of very high quality.

You should stick to a name brand, made for a motorcycle. These makers know that a motorcycle has to withstand vibration and be able to generate a lot of power on demand in order to start a engine.

Another reason to stick with a battery recommend for your motorcycle is the cold-cranking amp rating. Even if a battery is rated at 14-amp-hours, it still might not be able to start your engine. An electric starter requires a lot of power in a hurry, which is much more demanding than, say, the battery of a water pump, which is required to deliver steady power over a long period. The cold-cranking amp requirement for a large motorcycle engine might be over 300 amps.

For now, the lead-acid batteries still does the job well. But there's new technology on the way. Some companies already work on making dry lithium cells to replace lead-acid batteries in the motorcycle world. Lithium batteries can be much lighter than traditional units and have the potential to deliver the same amount of power. Cost is an issue for now, but expect that to change soon.