Motorcycle Battery Maintenance

Tip: There are dozens of parts on a motorcycle that could be checked on a regular basis and there is nothing wrong with check all those parts. But try to slim the list down to the most important items so you still have time to ride.

The Battery

THE BASICS

First things first. A 12-volt battery is not a 12-volt battery. Twelve volts is just a nominal, convenient term used to distinguish one battery from another. A fully-charged 12-volt battery, allowed to "rest" for a few hours (or days) with no load being drawn from it (or charge going to it), will balance out its charge and measure about 12.6 volts between terminals.

When a battery reads only 12 volts under the above conditions, it's almost fully depleted. Actually, if a battery's resting voltage is only 12.0 to 12.1 it means only 20 to 25% of its useful energy remains. It's either a goner or it has been deep cycled, and a battery can only be deep-cycled a limited number of times before it is indeed dead.

12-volt batteries supply useful energy only through a limited range -- from over 14 volts (when fully charged and unrested) down to 10.5 volts in use/under load (when lights dim, your motorcycle is hard to start). No 12-volt battery will remain at over 14 volts for more than seconds unless it's being charged. The lowest limit is 10.5 volts (used in testing) and obviously unsatisfactory in practical use.



NOTES: Keep in mind that listed voltages are "Resting" Volts.



Maintaining Your Battery

Tip: Check the fluid levels on each chamber. If any chamber is low, carefully top it up. Use only distilled or deionized water, NOT tap water. Tap water has minerals in it that will not do the battery any good.

The humble battery is a very common cause for motorcycle breakdowns! Unfortunately they are awkward to get to and therefore do not get checked as often as they should.

A battery only requires a little monthly maintenance to perform perfectly. Keep the battery charged to 100%, recharging when the lights dim, the starter sounds weak, or the battery hasn't been used in more than two weeks. Other than that, follow this simple check list every month:

- Check the electrolyte level
- Top up only with distilled or deionized water, wear gloves and protective glasses. Top up in a well ventilated area, Beware of fumes.
- Keep the top free of grime
- Check cables, clamps, and case for obvious damage or loose connections
- Clean terminals and connectors as necessary
- Check inside for excessive sediment, sulfation or mossing
- Make sure the exhaust tube is free of kinks and clogs
- Replace caps firmly
- Finish up by testing the battery with either a hydrometer or voltmeter. To extend the service life of your battery, make monthly battery maintenance part of your routine.

Use only distilled or deionized water, NOT tap water. Tap water has minerals in it that will not do the battery any good.


Storage can be hard on batteries. In fact, non-use can leave them unable to hold a charge.


Store your bike in a place that is always warmer than 32 degrees. If your bike is outside remove the battery from your bike and store it in a location that is always warmer than 32 degrees. This will insure that your battery does not freeze and crack.

If you remove the battery from your bike DO NOT store it on a concrete or metal surface, place the battery on a wood or other non-conductive surface. Batteries stored on concrete or metal will discharge over time.

Place a charger on your battery. A battery tender with float mode wil work best for times when you are not riding. A battery that is fully charged will have a longer life and is less likely to freeze during cold winter weather.