Motorcycle battery care: charging and checks

A dead battery is one of the most common reasons a bike will not start. Most of them can be avoided by keeping the battery charged, the terminals clean and by not leaving the bike standing for weeks.

Signs of a weak battery

Slow or hesitant cranking, or only a click when you press the starter.
Dim lights or a dash that resets when you start the engine.
A battery that is more than a few years old, or one that loses its charge after a short time standing.

Check the terminals

Look for white or green corrosion and for loose connections.
Switch the ignition off before you work, and clean corrosion with a brush, as your manual describes.
Make sure the clamps are tight, and that the battery is secured in its tray.

Keep it charged

Short trips and lots of starting use more charge than the bike puts back. Take a longer ride from time to time.
If the bike stands for weeks, use a charger designed for motorcycle batteries, often a smart or maintenance charger, set to the right type of battery.
Do not use a car battery charger on a motorcycle battery unless it is meant for it, because a high charge current can damage it.
Follow the instructions for your battery type. Lithium batteries need chargers made for them.

Working safely

Charge in a ventilated place, away from sparks and flames.
When disconnecting, take off the negative (−) terminal first, and connect it last.
Wear eye protection and gloves. Battery acid can burn skin and damage clothes and paint.

When to replace it

If a fully charged battery still struggles to start the bike, or loses its charge in a few days, it is probably at the end of its life. A workshop can test it. Check also that the charging system is working, so a new battery does not fail for the same reason.

Battery types, chargers and charging settings differ between bikes. Follow the owner’s manual and the battery maker’s instructions.