I am guilty of leaving my key in the ignition or the lights on only to come back to my bike and it was completely dead. Luckily, I was always able to bump start it and get it going but I wondered how long it would take to charge my motorcycle battery by riding it.

Most Motorcycles with a good electrical system can adequately charge the battery by riding the motorcycle at freeway speeds for 30-45 minutes. 

This of course depends on the condition of your battery and how depleted the battery is. iN the event that your battery died and you were able to jump-start it, I would recommend that when you get to your destination that you place your motorcycle battery on a charger. This will ensure that your motorcycle battery is topped off and ready to go the next time you hop on it.

In this article, we are going to break down how the battery on a motorcycle is charged in the first place. Along with all of the components of a motorcycle charging system and how they work.

How does my motorcycle charge the battery?

Electricity can be produced by passing copper wire through a magnetic field. The more copper wire that is passed through a magnetic field, results in the creation of more electricity.

Motorcycles use this method of leveraging the motion of the engine (kinetic energy) to spin magnets (also known as the rotor) around tightly packed copper coils (the stator). It is through this process that the motorcycle is able to create electricity to charge the battery.

The electricity that is produced is in the form of AC or alternating current. In order to store electricity in the battery, this current will need to be changed to DC or direct current as only DC current can be stored in batteries. Motorcycles are able to accomplish this by using devices called the rectifier and the regulator.

Alternator vs Stator

The term “alternator” is typically used to describe the device that converts motion into electricity for vehicles. In a vehicle, the alternator is all one unit while on a motorcycle an alternator is typically referring to the 3 separate components (stator, rectifier, and regulator) that make up the charging system.

The stator is a cylinder of tightly wound copper coils. These copper coils are all connected and all feed to the stator electrical wire. While the stator is stationary the stator rotor is a cylinder that houses the magnets and spins around the stationary stator. As the magnets spin around the stator, it generates electricity and sends it through the stator wires to the rectifier.

The rectifier is the unit that takes the electricity from the stator that is AC (alternating current) and converts it to DC (direct current).

The regulator is the unit that regulates the voltage of the electricity. The voltage needs to be maintained within the limits of 13.5 to 14.5 volts to properly charge a 12-volt battery. Most motorcycle batteries are 12.6 volts fully charged and rested. The voltage needs to be about 12.6 volts in order to charge the battery. Once the regulator produces the appropriate amount of voltage it then converts any additional electricity into heat. This additional heat is dissipated as the motorcycle moves and airflow removes the dissipated heat.

Most motorcycles have one unit that is a rectifier and regulator. This single unit makes it easier to maintain and replace if it goes bad or is faulty.

Different types of batteries

Most motorcycle batteries are all 12-volt batteries however they are all not created equal. Each motorcycle manufacturer has different space requirements based on the size of the battery it needs for the type of engine the motorcycle has. This means most motorcycle batteries are going to be in different shapes and different sizes. While the motorcycle battery sizes may differ the voltage will remain the same.

Motorcycle batteries come in four different types. We are going to break them down so you can see the pros and cons of each type of battery.

Conventional is the most common of the batteries. This can also be referred to as a traditional or a wet battery. These are the oldest types of batteries that use lead plates soaked in an acid solution to generate energy. Since the acid is a liquid it makes these types of batteries vulnerable to heat and vibrations.

Gel batteries are the most similar to conventional batteries but use a gel solution instead of the liquid acid solution. This gel solution lends itself to be used in more deep cycle batteries where energy needs to be stored for a long term. These batteries are typically used in boats or solar charging systems. Gel batteries aren’t typically used in motorcycles as they are not the best for assisting in the ignition of the motorcycle.

AGM stands for absorbed glass mat. These batteries utilize the same chemical reaction as the lead-acid batteries. However, these batteries are sealed and have a fiberglass mat that separates the plates inside the battery. This plate acts as an absorbing barrier that fills in the gaps between the plates leading to a lighter more durable battery. These batteries also tend to come with stainless steel battery posts that prevent corrosion on the terminal posts.

Lithium batteries are short for lithium-iron-phosphate. These are the newest types of batteries and are the most expensive. They do not contain lead plates or liquid acid but rather create energy through passing lithium ions from what is called the “anode” to the “cathode” and back again.

  • Cathode: stores lithium ions and releases them to the anode when the battery is being charged.
  • Anode: stores lithium ions and releases them to the cathode when the battery is being discharged.

Does my battery charge while my motorcycle is stationary

The electrical system on motorcycles is made to produce enough voltage to keep a charged battery topped off. This means your battery will technically be charging while you are at idle to maintain the battery's 12 volts.

However, the electrical system on a motorcycle is not designed to charge a dead battery. If your motorcycle has a dead battery and you manage to jump start it, leaving it running at idle will not produce efficient voltage to adequately charge your battery. You will need to maintain at least 3k RPM or more for 30 - 40 minutes to charge your battery.

How to tell if your battery is dead or dying

If your motorcycle is having sluggish starts it can be a sign of a dying battery. However, the best way to test your battery is with a voltmeter.

A healthy 12-volt battery will register on your voltmeter as 12.6 - 12.8 volts at rest. If your battery fails within the range of 12.5 - 13.5 volts it is considered a serviceable battery. Once a battery falls under 12.4 volts your motorcycle will struggle to start and if it hits 11.8 volts the battery is considered dead.

If you have a traditional or lead-acid battery its capacity to hold a charge is reduced every time the battery dies. This damage is irreversible so letting your battery die multiple times may kill it permanently.

A dead battery can be charged back to working condition by riding the motorcycle at freeway speeds for 30-45 minutes, by using a trickle charger, or a battery tender. If you are looking for a trickle charger or battery tender we would recommend the Noco Genius (find it here on Amazon). With some trickle chargers or battery tenders, you can under or overcharge your batteries depending on the battery type. With the Noco Genius, it handles all types of batteries from traditional, Gel, AMG, and Lithium.



I grew up working on my own cars and motorcycles and 15 years later I love still getting my hands dirty.