How to Choose and Use the Right Motorcycle Battery Charger

From Harley-Davidson to the Kawasaki in Top Gun to the Ducati-inspired Batcycle, motorcycle fans love a good bike.

If you want yours to love you back, you need to charge the motorcycle battery once in a while.

You need to charge your motorcycle battery about once a month unless you drive your Harley, Honda or Suzuki motorcycle often. Even then, the bike will recharge its battery only when it’s in motion. Whether your motorcycle has a stator or alternator, both need movement to send amps back to the battery. Also, alternators and stators are not battery chargers. Their job is sending electricity to the lights, engine and maybe the battery. If your motorcycle battery is 50% drained, you’d need to drive for hours to recharge it from the engine alone. Just idling your bike won’t recharge its battery. (Besides, where’s the fun in that?)

That’s why you need a motorcycle battery charger. But which one?

How to choose the right motorcycle battery charger

To pick the right battery charger, check your motorcycle battery label for three critical pieces of information:

• The battery type: AGM or flooded
• The voltage: 6V or 12V
• The amps: The Ah rating

In most cases, you can recharge your motorcycle battery with a trickle charger (also called a battery maintainer.) It will take 1-3 days to charge your motorcycle battery, depending on the charger and how drained your battery was. That said, a slow, gentle charge is the safest way to get the most life out of your motorcycle battery.

Let’s get into the specifics.

Check your motorcycle battery label for the letters “AGM.” Absorbed glass-mat (AGM) batteries need a different charging algorithm than regular batteries because they can absorb so many amps. Regular battery charging can break AGM batteries. Likewise, you could ruin a regular motorcycle battery if you use the AGM setting on your battery charger. If your motorcycle battery doesn’t say AGM, it might say wet, flooded, conventional or traditional because it has loose liquid inside.

En resumidas cuentas: Only use a battery charger with a setting that matches your motorcycle battery. Check your battery charger’s instructions to make sure it works with your type of motorcycle battery.

RELATED What Is an AGM Battery and What’s the Big Deal?

Check the battery label for the voltage. Modern motorcycles use a 12-volt system, which means a 12-volt motorcycle battery. A 12-volt battery means your turn signal bulbs, the digital display and the ignition switch all use 12 volts. Most battery chargers and trickle chargers have a 12-volt battery setting since 12 volts are the automotive standard. But if you’re riding a vintage bike or a dirt-spraying off-road bike, you might have a 6-volt system with a 6-volt battery.

En resumidas cuentas: Most battery chargers have the right voltage for your motorcycle battery. If your battery label shows a 6V, then get a charger with a 6V setting.

Check the battery’s amp-hour rating. Also abbreviated Ah, the amp-hour rating shows the battery’s capacity, as in how much power the battery can store, which is different than its cold cranking amp rating.

Battery chargers come in a variety of amp sizes. Amp ratings tell you how strong of a battery charger you can use. You need a battery charger that will give only 10% of your battery’s amp rating. If your motorcycle battery has a 20 Ah rating, you should use a 2-amp or 1-amp battery charger. Most motorcycle batteries have only 10-30 amp-hours, so a 1-amp battery charger will do you fine.

En resumidas cuentas: Pick a 1-amp charger or use the lowest amp-setting that your battery charger offers. Otherwise, you could overheat and damage the battery.

RELATED The Essential Steps to Charging a Car Battery

Do you need a special motorcycle battery charger?

No. A 12-volt car battery charger that can charge AGM batteries at 1-2 amps would double well as a motorcycle battery charger. If your smart battery charger has the right settings, you can use it for both your car and your motorcycle.

Motorcycle batteries charge the same way as car batteries. Plug them into the wall, connect them to a battery and wait until the indicator light says it’s done.

What matters is choosing the lowest amp rating while matching the volts and battery type.

Some battery chargers can push more amps, from 4 to 10 amps. But that can damage your motorcycle battery.

Should I charge my motorcycle battery at 2 or 10 amps?

Choose 2 amps or fewer when charging your motorcycle battery. You may think more amps will charge it faster. However, that’s the fastest route to killing your motorcycle battery.

Moving electricity around creates heat. That’s why your phone warms up when you recharge it. More amps cause more heat. Motorcycle batteries have an electrolyte-water mixture that conducts electricity inside the battery. Too much heat can disturb that mixture, essentially drying out your motorcycle battery.

Choose a low amp setting when charging your motorcycle battery.

Can I use a 12-volt charger on a motorcycle battery?

If your motorcycle battery is 12 volts, then yes. That said, the charger's voltage should match the battery voltage. You could damage both if you mismatch voltages. Some motorcycles have 6-volt systems, and they would require a 6-volt battery charger or a smart battery charger with a 6-volt setting.

Does idling a motorcycle charge the battery?

Idling your motorcycle is the least effective way to charge your motorcycle battery. Some motorcycles have an alternator, like a car, for generating power for electricity. Some use a stator. Both require significant RPMs from the engine rotor.

You see, your motorcycle’s engine recharges the battery out of leftover energy it generates when the bike is in motion.

If it’s idling, it’s not in motion. It’s just spending gas to sound pretty.

You’ve got to put the bike in gear and hit the highway for the engine to charge the battery. You can also use a motorcycle battery charger to maintain it, but let’s face it: Riding it is more fun.