The Ultimate Guide To Motorcycle Batteries

Your average 12-volt motorcycle battery consists of a plastic case containing cells. Each cell has both positive and negative plates immersed in an electrolyte solution.

The battery is used to crank the engine in modern push-start motorcycles, power lights, display screens, and sometimes stereos. 

While the motorcycle is running, an electromagnetic charging system converts some of the engines physical energy back into electrical power to recharge the battery.

On average, a rider can expect their motorcycle batteries to last around 48 months (4 years), as long as they properly cared for, and the bikes charging system is performing up to standards

Types Of Batteries

In The Old Days

In days past, when the kicker was the only way to start the engine, batteries had a relatively easy life. They were used to power lights and provided the juice for an occasional toot of the horn.

Then Things Changed

In particular, the invention of the electric starter and its wide-spread implementation into modern motorcycles. The electric starter began making demands that taxed the conventional 12-volt lead-acid battery. This kick-started a wave of innovation in the field of motorcycle batteries...

Electric starter

There are a few basic categories of motorcycle batteries, and it is very often to become lost or confused about what you need for your bike.

Maybe your bike only works with one type of battery, making your decision relatively easy, but you also may have a bike that’s designed to work with multiple different battery types, in which case you can easily find yourself at a crossroads. Below I will outline the most common battery types that you will run into.

Conventional

The conventional battery has access points to each cell, and each one of these cells does need to be maintained.

The fluid level must stay above the battery plates at all times. Conventional batteries also have a vent tube, so make sure its exhausted out in the appropriate port on your application and ensure that there are no kinks or bends in it. The conventional style battery uses simple lead-acid plates with free-flowing acid.

These are batteries that do need to be maintained and are considered to be a value-priced product.

AGM

The next step up from the conventional battery is the AGM type. These are the most common types of batteries that you will find at your local store or motorcycle repair shop.

Unlike the conventional battery, there are no maintenance access points to the cell, and it is a non-spillable maintenance-free battery.

The Absorbed Glass Mat (AGM) technology inside each one of these cells is where the electrolyte is poured in during the manufacturing process and is then absorbed by the glass matt separators in each cell. This means there is no free-flowing acid in these batteries.

AGM batteries are sometimes referred to as starved electrolyte batteries. There is a thin ultra-fine layer of fiberglass that lies between the battery plates. These sheets of fiberglass are saturated with about 95% of what they can hold.

This mat is then packed and compressed between the plates before being welded into place. Because the contents of the battery are packed so tight, they are almost completely immune to the effects of vibration.

AGM batteries also offer quite a jump in cold-cranking amps and starting power in comparison to its conventional counterpart. They have an abysmal amount of resistance to electricity, which when combined with their easier ability to migrate acid allows the batteries to release and take on far more amperage when compared to their competitors.

Another nice advantage of AGM batteries is that they are accessible to be chargeable to the same charging systems used in tradition lead-acid batteries, and charge four times faster on average.

Gel Cell

Gel cell batteries posses a type of gel that is composed of silica in which the electrolytes are suspended within it.

This gelatinous material allows the massive amounts of electrons to move between battery plates, but because of its viscosity, the fluid cannot leak out if the battery case is damaged in the advent of a wreck.

Gel cell batteries are usually a little more expensive than their AGM rivals mainly due to their lack of production and difficult to service. Often to even use a gel cell battery, a special regulator will have to be installed to work with the existing alternator.

Lithium

Lithium-ion units are the latest in battery technology.

They're lighter weight, more energy dense, and non-toxic. In fact, they weigh almost five times less than traditional lead-acid batteries.

They also take up about 30% less space, which can even leave you with a little extra storage space.

Lithium-ion batteries offer a considerable advantage in cranking power over traditional batteries and have a very low self-discharge rate, which means that they won't drain themselves down over time. This makes them especially ideal for seasonal riders who will often store their bikes away for months at a time.

The main drawback is their price, which is almost 30% more than a lead-acid battery. In addition to this lithium-ion batteries cannot be allowed to drain. If you accidentally leave a key turned on for too long, and your battery drains, it can often cause irreparable damage. Whereas traditional lead-acid batteries can usually be brought back from near dead conditions.  

Difference Between Car And Motorcycle Batteries

This is one of the most common questions asked, and the answer lies in the amount of current that they provide.

Cars

A car’s battery is designed to provide a high amount of current for a short window of time. This is known as micro-cycling.

This surge of current is needed to turn the large automobile engine over during the starting process. Once the engine starts, the alternator provides all the power that the car needs.

Used in this way a car battery can last some years.

To provide greater starting power, a car battery uses thinner plates to increase the plates surface area.

Motorcycles

Motorcycle batteries are designed to provide a steady amount of current over a longer window of time. They can provide a surge when necessary but not as much as a car battery can.

Motorcycle batteries are also designed to be discharged over and over again (something that would ruin a car battery very quickly).

To accomplish this, they sometimes use thicker plates or glass mat separators in the case of AGM batteries to increase the life of the plates with a positive charge.

How Do Motorcycle Batteries Work?

Batteries work by converting chemical energy to electrical energy.

A single cell consists of a certain makeup of parts, called electrodes, that are inside of a holder known as an electrolyte. While they are either gaining or losing energy, ions (particles with a negative charge or a positive one) engage in a reaction with the electrolyte and material to essentially craft electrons.

These electrons transfer through the completed circuit external to the battery, thus creating an electrical current.

For Those Of You Who Are More Scientifically Inclined

The electrolyte, which is made up of sulfur-based acid as well as water contains charged hydrogen and sulfate ions. The hydrogen ions are positively charged and counteract the negatively charged sulfate ions.

When you kick start your ignition and power on a light, radio, or fuel pump, the negative sulfuric ions shift to the negatively charged plates thus losing their charge. The remainder of the positive sulfate ions combines with the activation material on the plates to form what is called lead sulfate.

This, in turn, reduces the electrolytes strength, after which sulfate ions on plates become a type of insulator against the electricity.

The unnecessary electrons release from the battery's negative terminal, through the various electrical devices (your light, radio, fuel pump, etc.), and flow back into the battery from its positive terminal.

After returning the battery, the electrons bond to the plates with a positive charge, lead dioxide (formed on the plates) engages in a reaction with the positive to create water (pure H20), and then lead sulfate is formed from the reaction of sulfuric acid and lead.

The constant motion of ions through the current is created by electrolytes present. Meanwhile, the battery cell becomes depleted; these ions decrease in number as the entire area is engaged in a way for them to bind to also decreases due to excessive sulfate coating.

Now if you’ve had much experience with motorcycles, it's like that you discovered that if your battery is unable to crank your bike, and you continue to try, after a few tries you will find that it almost appears to be dead. If you come back outside 30 minutes later and try again, it almost seems as if its power level has been miraculously restored.

Alternatively, when you forget the ignition in the “a/c” position overnight where a few small lights or radio is constantly draining the battery, it will be completely dead the following morning, and will not “come back to life” as it did in our previous example.

To find the answer, let’s take a look back inside the battery.

As we learned above, electricity is essentially made on the surface of the plates, and a heavy flow (such as attempting to crank an engine) rapidly reduces the electrolyte on the plates. However, given a short period of rest, more acid can be released throughout and replenish the plates surface, thus “bring it back to life.”

In the case of the switch that was left on overnight, the acid is depleted far more slowly than the rapid drain of the starter. This means that the rate of diffusion is still enough to keep a steady level of volts without interrupting the current flow. Because of this slow drain, every bit of acid is consumed, and the battery now needs a charge to function again.

How Long Do Motorcycle Batteries Last?

There are quite a few factors which must be taken into account to answer this question properly. The biggest variable in the equation is you. The way you care for your battery can make or break how long it lasts. If you take good care of a motorcycle battery, you can usually expect it to last between 2 and five years.

Some other factors to consider are:

The Type Of Battery

As we learned above, not all batteries are created equal. It is important to understand the differences between batteries and weight them against your needs and desires. Some batteries require regular maintenance, such as the topping off of fluids, and still, others are maintenance-free.

How Often The Motorcycle Is Ridden

This is one of the most important factors when considering the life of your battery. Most batteries have what a called a self-discharge rate, in which they will slowly lose charge over time when they are not in use or being actively charged during a ride is.

Conventional batteries have the highest self-discharge rate, whereas Lithium-ion batteries are known for their ability to maintain shelf life for far longer. The bottom line is that the simplest way to keep your battery charged and in good condition is to ride it often. If you cannot ride it often, then it is probably wise to invest in a good electronic charging system.

How The Battery Is Used

The motorcycle battery is used for more than just the initial starting of the engine. It also is responsible for powering all of your lights, stereo, lights, and navigation. Many riders will leave their ignition turned on accidentally or purposefully after they've cut their engine off.

It almost goes without saying, but if the engine is off and you're still playing your radio, you can guarantee that your battery is rapidly losing its charge.

External Charging

If you are not in a position to ride your bike every day and opt for an external charging system you have quite a few options. The easiest is just to purchase a battery tender which provides your battery with a constant trickle of charge. It keeps the charge topped up and won't overcharge your battery.

External Charging

This is its primary advantage over traditional battery chargers which can have a propensity for overcharging and ruining a motorcycle battery.

How Do I Install My Motorcycle Battery?

S you’ve finally decided on what type of battery you want, you’ve purchased it and are sitting in your garage looking at your bike, and wondering where the battery goes, how it’s hooked up, and how it’s secured. Well here’s the process in 10 easy steps:

Prepare Your New Battery

If you're using a conventional non-sealed lead-acid battery, pour the electrolyte solution which should be in small cylinders into the battery chambers.

For non-sealed batteries, it is recommended to put a minimal amount of Vaseline or battery grease on the terminals to prevent or mitigate corrosion. Finally, make sure the battery is fully charged before use. It's always important to make sure the battery isn't faulty off the store shelf.

Locate Your Old Battery

Your motorcycle’s battery compartment is usually found directly under the seat, but some different models might feature batteries which located in other locations. If you are unsure, you should consult your owners manual.

Remove The Negative Cable

Always remove the negative cable before the positive cable when uninstalling an old battery. The negative terminal can usually be identified by its black color cable ends or by a minus (-) symbol. Use the correct size socket wrench to loosen and remove the bolt from the negative cable.

As you remove it, make sure to position it in a manner in which it won’t come into contact with the positive cable, positive terminal, or any other metal surface through which electricity can be conducted.

Remove The Positive Cable

The positive cable can usually be identified by its red color cable ends or by a plus (+) symbol. Use the appropriate socket, and follow the same instructions in the previous step, ensuring the cable doesn't come into contact with the battery posts after removal.

Prepare Your Bike

Check your cables for any cuts, frays, exposed wire or damage. Repair any damage you find before installing the new battery. Using a small brush remove any old dirt or debris from the cable connectors and apply a thin layer of battery grease.

Removing The Old Battery

The battery should come out easily. If you feel resistance when pulling the battery out, check around the battery compartment and make sure there is no dirt, corrosion, foreign objects, or important wires holding it back. If that's not the case, then check to make sure that the battery compartment walls haven't warped.

Any warping within the battery compartment should be repaired before installing the new battery to prevent damage or malfunction. Make sure that the old battery should be properly disposed of. The components of the battery can be toxic to people, animals, and the environment.

This means that they should not be dumped along with regular garbage. If you go to your local landfill or auto parts store, they should provide you with an appropriate way to dispose of your battery.

Insert Your Fresh Battery

If your new battery came with a set of nuts, insert them into the battery terminals now. Hold the battery above the battery compartment and make sure it is oriented with the positive battery terminal aligned with the positive cable and the negative battery terminal aligned with the negative cable.

Once you’ve checked for alignment, insert the new battery into the battery compartment making sure not to damage any other components that may be in the compartment.

Attach The Positive Cable

Follow the same steps from steps 3 and 4 to attach the positive cable to its post. Be sure not to over tighten the nut.

Attach The Negative Cable

Follow the same steps as above. Be aware that you may encounter some minor sparking coming from the terminal when you make contact. This is completely normal and nothing to worry about.

Close The Battery Compartment

Make sure that your battery is properly secured within the compartment, and then reinstall the seat or battery panel. Make sure that when you are reinstalling the panels that everything locks in securely. Trust me when I say you don't want a battery panel flying off while your speeding down the highway.

Battery Maintenance

As you’ve probably gathered from the information above, a well-treated battery can last a lot longer and save you both headaches and money. Here are some helpful tips.

Dealing With New Conventional Batteries

The first time a battery is charged is the most important charge of its life. Most batteries are dry-charged, and although they will perform adequately for a while without additional charging, the state of the charge is normally at 45-50% after servicing. Here are some things you can do to ensure a full charge:

  • Fill the cells slowly, allowing the air to dissipate from the cells.
  • Don’t fill the cells to the top! This can ruin a battery by allowing one bad or weak cell to contaminate the others.
  • Use only distilled water to top off the low cells.
  • After letting the electrolytes to settle and absorb into the plate material, charge the battery for at least 18 to 24 hours at a rate 1/10th of the batteries amperage.

Winter Storage And Trickle Charging

If you plan on storing your motorcycle over the winter months, be sure to hook the battery up to a trickle charging device.

These chargers are specifically designed to charge batteries without overcharging them slowly. In other words, they will ensure the battery is always topped off, but never too full.  

A battery that has been trickle charged all winter will likely come out of storage the same way it went it- with plenty of power and ready to crank your engine.

Conclusion

We hope that you enjoyed this guide and learned something new about motorcycle batteries in the process. Maybe you are a rookie biker or an experienced rider, but whatever the case, it never hurts to learn more about how your motorcycle works. If you liked this, please check out our official Buyers Guide where we rank the top batteries!

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