How does a motorcycle battery charge while it is idling?

✓ SAVINGS TIP Check out whether you are paying too much for your motorcycle insurance

Comparing quotes can help you save money.

Enter your zip to get started.


A motorcycle battery can be a big help for motorcyclists. While there are some simple principles that can be followed about the battery, others may require more explanation.

It is vital to understand how the battery charges. Many riders know that the battery charges while the bike is being driven, but many are not sure if the battery charges when the motor is stopped.

How does a motorcycle’s battery charge when it is idling? The motorcycle battery charges technically while it is running, but not as much as when it is going faster. A motorcycle can provide 13, 14 or 15 amps for a normal ride while an idling motorbike provides only 1 amp.

Although this may seem complicated, I can help you understand what happens to your battery during idle.

How the Battery Is Charged While Idling

The battery is actually charging while the motorbike is running. It is a very small amount of charge, so it won’t be able top off a dead battery. An electrical system for a motorcycle is intended to keep a healthy battery charged, but it is not meant to be used to charge a dead one.

Look at trickle chargers. Most have either a 2amp or 6amp quick charge setting. This is what your bike needs to receive a constructive charging. By your bike just sitting there idling, you’re probably putting in less than one amp. That is such a small amount that if you let your motorcycle idle for 10-15 minutes, you’re really not charging your battery all that much.

A stator is a component of most motorcycles. It is designed to produce about 15 volts. The battery is 12.6V. If you take a digital reader and connect it to the battery while its running it’ll say something along the lines of 13, 14, or 15 volts. While that is true when the bike is running, it’ll go back down to 12.6 -ish when you turn it off. If the battery was dead before, it’ll go back down to whatever low voltage it had before getting started.

The motorcycle provides more voltage and amperage than the battery. This is necessary to charge the battery during the bike’s operation. The stator will output a small amount extra amperage during idle to provide a little charge to the battery but not enough for a complete charge.

The stator always outputs 13-15amps. However, the stator can produce more voltage if the engine is running for more revolutions. This excess amperage can be used to power lights, sparkplugs, and other electrical components. When the motorcycle is fully-on, it charges its battery.

How to optimize idle charging

Motorcycle batteries can be finicky, which is an understatement. They can be costly so it is understandable that riders will do their best to extend the battery’s lifespan.

There are some things that you can do to give your bike more power if your commute is hectic and you need to keep your bike running.

You can do this by revving your motorcycle a little while you’re at an idle. It can be done by keeping the engine in a neutral gear, twisting the throttle to between 3,000 and 4,000 RPM, or by adjusting the air/fuel screw so that the engine idles at a higher level. The engine can be revved to provide more amperage than a simple idle but not as much as it would during normal riding.

With that being said, many may wonder if it’s good for a motorcycle to rev it like this. In moderation, revving a motorcycle engine isn’t bad. The word revving is short for revolutions per minute that’s happening inside the engine. Revving it is just making the engine do what it’s already doing, just a little faster.

You can damage your motorcycle’s engine if you revve the engine too often (meaning, for more than five seconds per rev), Moderation is important. A few revs should be enough to give the battery a boost. Click here to find out more about how a motorcycle engine reacts when it is revved.

Why your motorcycle may struggle to charge during idle

The problem with a motorcycle running is usually due to a problem with its battery. When I first began riding motorcycles, I always checked the battery to see if my bikes were having trouble starting.

If you’re searching the query about whether or not a motorcycle charges the battery during an idle, you may have run into issues during idling. While the battery is often the culprit of issues a motorcycle can have, it likely isn’t your problem in this case.

A motorcycle battery’s primary function is to start the motorcycle. After the motorcycle has been started, the stator (or alternator), takes over and powers all the electric components. The bike is powered by the battery, so it doesn’t have any essential functions. So if you didn’t have much of a problem getting your motorcycle started, you’ll know the battery is okay.

The carburetor is the most likely culprit if you experience poor idle when riding your motorcycle. More specifically, the carburetor may have a vacuum leak which means there’s too much air in the air-to-fuel ratio the carburetor is giving the engine. Another possibility is that the carburetor has a fuel leak, which can cause the engine not to get enough fuel to function properly. A timing problem in the carburetor may also be a possibility, meaning that the fuel/air screw should be adjusted.

You can find more information about why your motorcycle struggles to idle or sputters in my article, click here.

Do Too Many Idling and Battery Failure Causes?

We’ve discussed that the most important function of a battery on a motorcycle is to get it started. The stator recharges the battery so that it can be used again. You may ask yourself that if a regular run and normal RPM’s is what charges the battery, what will constant idling do and will it help the battery at all?

If you’re like me, you’ve found yourself in occasional stop and go traffic while riding your motorcycle; this means your motorcycle will be idling a lot. Although idling can charge your battery, it will not fully recharge it.

Good news: All it takes to charge the battery for the next start-up is a few minutes on the bike. Say you are stuck in stop-and-go traffic, you’ll still be using the throttle several times to move the bike forward those few feet. As long as you get those several minutes in of a good run on the motorcycle, you shouldn’t have to worry about how much idling you’re doing.

You might also just want to start your bike for a quick clean up. If you intend on doing this for longer periods of time or doing it several times in one day, be sure to give the motorcycle a good few revs while it’s stationary so you can ensure that battery gets the charge it needs.

Leave a Comment