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Symptoms of Bad Battery on a Motorcycle

Symptoms of Bad Battery on a Motorcycle

The battery is an important part of a motorcycle, providing the electrical power required to start the engine, and it also generates the electrical energy needed to operate lights and electronic systems. Moreover, a motorcycle’s battery is also responsible for supplying additional current to meet the electrical demands of the motorcycle, especially when the charging system is unable to keep up. Furthermore, your motorcycle’s battery acts as a voltage stabilizer for the motorcycle’s charging system. Hence, a motorcycle’s battery plays a vital role in the overall functionality of the machine, making it crucial to ensure that the battery itself is working properly.


A bad battery on a motorcycle can lead to many problems, including difficulty starting the bike, reduced engine performance, dim lighting, and other electrical issues. Moreover, a failing motorcycle battery can also leave you stranded, posing various problems, especially during long-distance travel. Luckily, the signs of a bad battery are easy to recognize. This article aims to explore the symptoms of a bad battery on a motorcycle, enabling you to identify a failing battery and take preventive measures before it causes significant problems for you.

1. Common Types of Motorcycle Batteries

Due to the ever-advancing motorcycle technology, motorcycles are powered by different types of batteries, including wet battery or conventional unsealed lead-acid battery, high-performance flooded battery, AGM battery, gel battery, and lithium or dry battery. Each motorcycle battery type has its unique benefits and downsides.

1.1 Conventional Flooded Battery

The conventional flooded battery is the most common type of motorcycle battery, also referred to as wet cell battery, unsealed flooded battery, and lead-acid battery. The traditional flooded motorcycle battery is readily available in 6V and 12V configurations as most standard bikes run on these two configurations. Being the most cost-effective motorcycle battery option, flooded batteries are easy to replace.


Different companies have also introduced high-performance flooded batteries with longer life spans and lower discharge rates. The cost of high-performance flooded batteries is more than the traditional ones; however, they greatly improve the ride quality and offer the most value for the money.


The 6-volt lead-acid motorcycle battery typically features three stoppers, while the 12-volt lead-acid battery comes with six stoppers. These batteries also come with a white case with marks indicating maximum and minimum battery fluid levels. While charging and discharging, flooded or wet motorcycle batteries emit hydrogen gas, which is highly toxic and flammable. It is highly advisable to prioritize safety measures when charging your motorcycle battery in the home garage.


Lead-acid batteries tend to lose the electrolyte over time; therefore, they must be inspected regularly for low fluid levels. You can replenish the battery electrolyte levels by adding deionized or distilled water.

1.2 Absorbent Glass Mat (AGM) Battery

The absorbent glass mat (AGM) motorcycle battery features internal fiberglass separators that absorb liquid electrolytes and store charge in a dry state, while the lead-acid battery stores electrolytes in a liquid state.


Since the AGM battery stores electrolytes in a dry state, it is a low-maintenance battery. Moreover, the AGM batteries feature a permanent seal, ensuring maximum safety by preventing fluid spills and leaks. Hence, AGM batteries are ideal for bikes designed for off-roading, navigating rough terrain, and adventure rides. These highly durable and long-lasting sealed dry motorcycle batteries have high-temperature resistance compared to lead-acid batteries. However, they are more expensive than their wet unsealed counterparts.


The low-maintenance AGM motorcycle batteries do not require constant fluid-level inspection. These batteries usually come with acid separately. Once the battery is filled with acid, the cap is placed on top to seal the battery. AGM batteries usually come with a black and a stopper. These non-fillable, sealed batteries store electrolytes in a paste-like consistency. To recombine oxygen and hydrogen into water, the AGM batteries utilize pressure while charging.

1.3 Lithium Battery

Lithium or dry cell motorcycle battery is the most powerful battery type that has the lowest self-discharge rate and greater life span. These efficient motorcycle batteries are high-performance and can support the most robust and fully-decked motorcycles. The biggest advantage of a lithium battery is its low charging time and self-discharge rate.


You can easily store it for long periods of inactivity without the need to charge it regularly. These batteries lose very little power and only need to be recharged once a month when not in use. When it comes to long-distance travel and adventure rides, you can rely on lithium batteries to not leave you stranded in the middle of nowhere.


The biggest downside of the lithium batteries is their high cost. But with proper charging and cleaning, you can easily use these batteries till their expiration date, effectively avoiding frequent and expensive replacements. Lithium batteries are essentially maintenance-free as you need not monitor fluid levels. Moreover, these sealed dry motorcycle batteries eliminate all risks of brake fluid leaks and spills.

1.4 Gel Motorcycle Battery

The Gel motorcycle batteries are essentially lead-acid or wet batteries; however, the electrolytes in this battery type are in a silica gel form. The gel acid battery offers improved safety, high-temperature resistance, long lifespan, and vibration resistance.


The casing of Gel motorcycle batteries is available in blue, black, or gray and comes loaded with acid in a gel-like consistency. The gel motorcycle batteries feature a sealed top so the motorcycle owners need not adjust the level of acid inside the battery. Since gel acid does not move inside the battery, gel motorcycle batteries are mounted at a specific angle to make the flow of charge between terminals possible.


The gel motorcycle battery has electrolytes wrapped in fumed silica, a gelling agent, that preserves the viscosity of the acid. Under pressure, these batteries effectively recombine hydrogen and oxygen to create just enough water required to maintain the gel-like consistency of acid.

2. Signs Your Motorcycle Battery Needs to Be Replaced

Several points of identification help you determine whether your two-wheeler’s battery is worn out and in dire need of a replacement or repair. The problems discussed below are always a clear sign that you need to act quickly to save your motorcycle’s battery from further deterioration.


It is advisable to consider an immediate battery replacement when you notice the following recurring issues related to failing motorcycle batteries. Since the symptoms mentioned infra may also be signs of other mechanical problems, it is best to consult a trustworthy motorcycle technician before replacing the existing battery.

2.1 Difficulty Starting Your Bike

If your two-wheeler’s battery is worn out, failing, or completely dead, then starting the motorcycle will become a hectic task. Any time you see your motorcycle not starting or igniting, the first component you should check is the battery. Since ignition failures may also result from other factors and mechanical malfunctions, it is safe to first rule out battery failure out of the equation. When a motorcycle’s battery is not performing up to its potential, it comes up short to power the starter motor that is responsible for firing/kick-starting the motorcycle. In such a scenario, the only possible solution to the declining battery is a quick replacement.

2.2 Reduced Performance in Cold Weather

A motorcycle’s inability to deliver as expected in cold weather can be easily attributed to a depleting or deteriorated battery. Low temperatures affect the chemical reactions taking place inside a battery to help it work at the optimal level, and as a result, the battery produces less electrical power than it does in warmer or favorable weather conditions. This reduced power production by the motorcycle battery becomes more prominent and identifiable in cold weather conditions.


It is also worth mentioning that the cranking power demanded by the engine to start is comparatively much higher in frigid temperatures than in warm weather, and if the motorcycle battery is already exhausted, it struggles to meet the engine’s power demands, resulting in slow and sluggish engine starts, hesitant electrical response, and performance cuts.

2.3 Dim Headlight

Dim motorcycle headlights are an unmistakable sign of a battery’s performance issue as the bike’s lighting system is highly dependent on a steady, uninterrupted, and sufficient supply of current from the battery, otherwise, it fails to perform at the optimal levels much like other electrical components of your two-wheeler. If the motorcycle battery’s charge is decreasing constantly, it has less than sufficient capacity to support headlights, making them appear dimmer and dull.


The dim headlights due to battery issues may be due to an aging power source, a failing charging system, or long periods of inactivity with zero battery maintenance. A weakened battery is incapable of providing the much-needed charge/voltage for lighting, resulting in faint lights. Ignoring this blatant sign of a depleting battery can jeopardize your and others’ safety on the road.

2.4 Horn Failure

Much like the bike’s lighting system, its sound system also draws electrical power from the battery, therefore, if you find your motorcycle’s horn failing it is a clear indication of battery issues and electrical hiccups as the amount of electrical energy required to produce sound is not supplied to the horn, leading to weak and irregular sounds or complete silence.

2.5 Frequent Jump Starts

If you find your motorcycle demanding frequent jumpstarts, it is definitely in need of a battery replacement as the existing power source is failing miserably to maintain the charge and supply power as needed. Jump starting is a quick solution to boost start your motorcycle’s engine when the battery refuses to do its job properly; however, the jumpstart fails to provide a reliable and permanent solution to the problem, which in this case is a degrading battery that is unable to store the charge.


Many factors are causing this phenomenon, including old batteries, internal impairment, and prolonged phases of inactivity. When out on the road, jumpstarting your motorcycle can provide a quick fix, but it is advisable that you immediately get your battery inspected by a certified technician and get it replaced to address the issue from its root cause. Ignoring repeat episodes of jumpstart can cause you unnecessary stress and inconvenience.

2.6 Electrical Issues

A compromised battery on a motorcycle can damage the entire electrical system by failing to meet its energy needs and causing unnecessary strain on it. Common electrical issues on a motorcycle include an inoperative horn, flickering and fading lights, difficult engine starts, and non-functional electrical components.


In addition to these, the bike’s charging system also gets unnecessarily strained as it strives hard to keep the charge from draining, eventually failing, and further exacerbating the deterioration of the bike’s electrical system. The signs of compromised electrical systems of a two-wheeler are quite similar to those of other automobiles and can surface as ignition issues, lack of power supply to electrically-powered parts, engine stalling, etc.

2.7 Corroded Battery Terminals

The motorcycle battery’s terminals are susceptible to corrosion and once it develops, it prevents your battery from functioning properly, causing quick charge drain for unexplained reasons. Initially, simply cleaning the corroded battery terminals can help curb the situation to some extent. However, if the corroded terminals are also broken, you cannot avoid getting a battery replacement.


To prevent this situation from substantiating in the first place, you must halt the development of corrosion and prevent the accumulation of rust through regular maintenance and thorough cleaning regimes, as clean terminals are at less risk of sulfation and damage.

2.8 Cracks, Bulges, and Deformation

Every time your motorcycle engine or electrical system creates problems, inspect the battery for any cracks or bulges on its casing. Physical deformations such as discoloration, fluid leaks, and other disfigurations are very easy to identify at a glance. All of these signs are alarming and dangerous; therefore, you must not ignore them and replace the existing deformed battery without any delay.

2.9 Battery Discoloration

As mentioned any changes in the shape, appearance, or color of your motorcycle battery must not slide by you unattended. Battery discoloration may be a result of electrochemical reactions occurring inside the power source that may lead to fluid leaks. The leaked fluid not only leads to the development of corrosion on the outer casing but also triggers discoloration. It is advisable to perform a thorough inspection of the motorcycle battery to find the main cause of discoloration.


Since this issue involves fluid leaks, it is prudent to let a professional handle this task as you might not have the necessary skills to deal with it. Eventually, the replacement of the old discolored battery is the only solution to ensure your safety and the bike’s longevity.

2.10 Sulfation

Battery sulfation is a phenomenon arising from charge deprivation of the battery. If you are not charging the motorcycle during periods of inactivity or if the battery is discharging itself, the lead active materials on the battery’s charging plates corrode. This is because sulfate from the battery's electrolyte results in the deposition of lead sulfate salt on the plates. Much like bulges, cracks, and discoloration, it is easy to identify this problem and take the necessary steps to fix it.


Once identified, charge your motorcycle battery fully to convert the lead sulfate salts into electrolytes with separate lead and sulfate ions. This reverse reaction of sulfonation helps free up the battery terminals from clogging caused by the accumulation of lead sulfate salts. If you do not address this problem on time, it will completely deteriorate the battery, leaving you no choice but to replace it.

2.11 Rotten Smell

The smell of rotten eggs emanating from your motorcycle battery is another obvious indication of looming battery failure. Contrary to the sulfonation process, in which undercharging the battery is the root problem, the rotten sulfurous odor from the battery is a result of overcharging or overheating.


When excess charge reaches the battery, it increases the temperature inside causing the sulfuric acid to evaporate. When these vapors of the acid escape from the battery casing, the pungent smell can be detected. Ignoring these signs can have extremely dangerous consequences, the most common one being battery explosion.

2.12 Battery Fluid Leaks

Lead acid batteries are highly prone to acid leaks due to severe oxidation. The leaking acid comes out from the cracks in the casing or corroded/broken terminals. In this condition, the battery cannot be revived and must be replaced immediately. Riding your motorcycle infrequently or storing it in extremely cold temperatures is a major reason behind acid leaks, as the fluid freezes, it pushes against the walls of the casing, causing them to expand, crack, and burst open.


The best solution to protect the motorcycle battery from cold weather is to store it properly in a temperature-controlled room, especially when not riding it for the season. If storing the entire motorcycle in a warm place is not possible, then remove the battery and store it in a room with a feasible temperature level. Reusing old motorcycle batteries or overcharging them out of neglect are also some of the most common reasons behind battery fluid leaks. Make sure you check the expiry date or age of your motorcycle from time to time, charge it mindfully, and replace it when it becomes unfit to do its job.

2.13 Charge Drain

A battery’s main purpose is to store electrical energy in the form of charge, and if the battery itself starts draining the stored charge immediately after full charging, it is a clear indication that it is dying. For ignition, engine performance, and functioning of the bike’s electrical system, this is not the kind of battery you want to rely on. A bad alternator can also be behind your motorcycle battery’s inability to hold a charge; therefore, it is best to seek professional help to deal with this symptom before opting for a replacement.

2.14 Inconsistent Volt-Meter Reading

Inconsistent voltmeter information is also a prominent symptom of a failing motorcycle battery. If you are using the voltmeter correctly, it should provide you accurate readings each time with minimal difference. But if you are getting inconsistent voltmeter readings, it is time to look for a battery replacement. Recording nothing on the voltmeter right after charging the battery is a highly alarming situation and must be dealt with promptly. Recording nothing on a battery when it has not been charged means it is just flat and requires recharging to function properly.

2.15 Hitting Expiration Date

A high-quality motorcycle battery from a trusted brand should serve you four years straight without any signs of wear or damage, provided any external elements have not interfered with its structure and performance. Despite top-notch motorcycle battery maintenance, these power sources have a limited lifespan, and once they hit their prescribed expiration date, they are bound to create problems for you no matter how carefully you have been using them. If you have successfully used a motorcycle battery for up to four years, you should be ready to replace it at the first sign of fading and consider getting a reliable replacement without any delays involved.

3. Things to Consider When Replacing a Motorcycle Battery

When replacing the motorcycle battery, it is best to consult the authorized dealership or the owner’s manual. In addition, consider the size, CCA, chemistry, and voltage of the motorcycle battery before buying.

3.1 Motorcycle Battery Size

When choosing a battery check its physical dimensions by your bike to ensure a tight and secure fit. For this, consult your dealership or the owner’s manual to find the right battery size for your bike’s make and model.

3.2 Motorcycle Battery Cold Cranking Amperes (CCA)

The cold cranking amps (CCA) of a motorcycle battery tell you how well your bike’s battery performs in frigid temperatures or the minimum current required to start the engine in cold weather. Motorcycle manufacturers provide the CCA requirements for each motorcycle in their multiple lineups, so you can find this information on the manufacturer's official website, in the owner’s manual, or by reaching out to the authorized dealership. A battery with a higher CCA is more reliable and has a longer life span; however, follow the CCA figures provided by the manufacturer to ensure the proper functionality of your bike’s electrical systems.

3.3 Motorcycle Battery Chemistry

Motorcycle battery chemistry is another important aspect to consider when choosing a replacement. It is important to install a battery that is compatible with your bike. If your motorcycle is designed to run on a lithium or AGM battery, it is not advisable to downgrade to a flooded/lead-acid battery. However, if your bike is powered by a flooded battery, you can certainly upgrade to a lithium battery as they are lighter and perform well in cold weather, provided your motorcycle is in good running condition and its charging system charges between 13.4V and 14.6V. However, each bike is different and may have unique requirements.

3.4 Motorcycle Battery Voltage

A wide majority of motorcycles are powered by a 12-volt battery; however, some motorcycles use a 6-volt battery. For proper working of the motorcycle, always make sure that the battery you buy matches the voltage requirements of your bike.

4. Motorcycle Battery Care and Maintenance Tips

Motorcycle batteries have a limited life span and to keep them running smoothly throughout that period, proper maintenance and battery care are essential. Proper battery maintenance becomes even more important during the off-season. When maintaining your motorcycle battery, it is best to follow the instructions provided in the owner’s manual. You can also follow the motorcycle battery maintenance tips provided below to increase the lifespan of your motorcycle’s battery:

4.1 Charge the Motorcycle Battery Regularly

When storing your motorcycle for a long period, it is essential to charge the battery regularly to avoid full battery discharge or sulfation. Lithium battery has a low discharge rate; therefore, it might not require frequent charging during periods of inactivity. However, when storing a lithium battery, make sure its charge is always around 50% to avoid deep discharge.

4.2 Use the Right Motorcycle Battery Charger

It is important to choose a charger that is compatible with your motorcycle’s battery voltage, amperage, and chemistry. A 12-volt battery must be charged with a 12-volt charger to ensure proper charging and avoid deep discharge. An incompatible charger can significantly reduce the current supply to the battery and slow down the charging process.

4.3 Avoid Storing the Battery in Extreme Temperatures

It is always recommended to store your motorcycle’s battery in a cool and dry place during periods of inactivity. When you ride your bike regularly, it is best to park it in shade and covered parking lots as direct sun exposure and sweltering heat can affect battery performance. On the other hand, try to keep your motorcycle’s battery covered with a battery-specific blanket as the battery may freeze in extremely cold temperatures, leading to permanent damage.

4.4 Do Not Overcharge the Motorcycle Battery

Overcharging your motorcycle battery negatively impacts its performance and shortens its life span. The longer you charge the battery, the greater the drop in its starting power and electrolyte levels. Since most motorcycle batteries are sealed, it is impossible to add water to prevent the loss of electrolytes.


Furthermore, overcharging can also distort the shape of cell plates, making it difficult to charge the battery in the future and compelling riders to replace it altogether. If you are unable to monitor the charging level, it is best to use a motorcycle battery charger that disconnects automatically or a maintainer.

4.5 Water the Flooded Motorcycle Battery

If your motorcycle has a flooded battery, regularly check the electrolyte level and make up for the loss by adding deionized water. However, do not add water if your motorcycle has a lithium or an AGM battery. AGM batteries are permanently sealed, opening the seal and adding water causes irreparable damage to these batteries, leading to expensive replacements. On the other hand, lithium reacts vigorously with water, forming highly toxic and flammable hydrogen and lithium hydroxide, degrading cell performance, and damaging the battery beyond repair.

4.6 Remove Corrosion from Battery Terminals

Corroded battery terminals can seriously damage your motorcycle’s battery cables. In addition, corroded battery terminals can cause a spark that may permanently damage the terminals and lead to rupture. Corroded battery terminals are also a common cause of reduced battery life and related electrical issues. If left unattended, corroded battery terminals may also damage other electrical systems of your motorcycle.


According to the Universal Technical Institute, “corrosion on or around your battery can cause increased resistance in the circuit, which disrupts the electrical current supply.”


Motorcycle batteries usually develop corrosion due to the following reasons:

  • Overcharging and Overheating
  • Motorcycle batteries that are frequently overcharged are more susceptible to corrosion. Sometimes, undercharging your battery can also increase the risk of corrosion. Moreover, riding motorcycles in extreme heat and parking bikes in direct sunlight can also increase the risk of corrosion in batteries. If you ride your bike regularly in summer, then make sure you check and clean the battery terminals regularly.

  • Fluid Leaks
  • Battery fluid leaks can also cause corrosion around the terminals.

  • Expiration Date
  • Motorcycle batteries usually last three to five years; they are more prone to corrosion near the expiration date. Make sure you are aware of the motorcycle battery’s expiration date for timely replacements.

    To prevent corroded battery terminals, thoroughly clean the battery and apply a coat of terminal protector. If only the positive develops corrosion, it may be a sign of overcharging and a bad voltage regulator. However, if the negative terminal develops corrosion, it is a sign of undercharging, so make sure you are using the right size of charger. Regularly clean your battery terminals to effectively prevent corrosion.

4.7 Schedule Maintenance Checks

While it is possible to perform motorcycle battery safety checks yourself, it is highly advisable to schedule maintenance checks with the authorized dealership or a trusted technician to identify issues with the electrical system. These will help diagnose any underlying issues with the battery. Also check for signs of corrosion, fluid leaks, discoloration, cracks, and changes in battery shape.

4.8 Ensure Secure Connections

Loose electrical connections can cause battery drain and reduce overall performance. Make sure all the electrical connections are secure. Tight and secure battery terminals and connections ensure uninterrupted current flow and prevent loss of charge.

4.9 Reduce Electrical Load

With so many aftermarket motorcycle parts available on the market, customizing a motorcycle has never been easier. While some motorcycle parts, such as motorcycle saddlebags, fairing, luggage racks, and sissy bars, enhance ride quality without causing any damage to the battery, other motorcycle add-ons, such as heated grips, heated seats, high beam lights, security alarms, audio and GPS systems, and auxiliary lights can drain your bike’s battery. Therefore, avoid adding too many electrical accessories to reduce the load on your motorcycle battery.

4.10 Replace Damaged Battery Seals

AGM and lithium motorcycle batteries are permanently sealed and essentially maintenance-free. However, conventional lead-acid motorcycle batteries feature seals that are susceptible to damage. If you notice worn-out battery seals and casing, replace them immediately as they quickly degrade the performance of the battery and increase the risk of fluid leaks.

5. Last Words

Discerning the symptoms of a fading motorcycle battery is indispensable to ensure your two-wheeler is performing adequately and meeting your expectations. Plus, your safety and other’s well-being when on the road also depend heavily on the motorcycle battery’s health. From dimming headlights to delayed engine starts diminished horn sounds, and unexplained electrical failures on the motorcycle can become a nuisance, making simple everyday tasks a huge struggle. Therefore, it is necessary to familiarize yourself with all the possible signs of a failing battery and keep an eye out for them.


A proactive approach towards your bike’s battery and overall maintenance helps solve many problems that shape themselves into costly repairs and replacements. It also offers peace of mind when traveling long distances, going out for a relaxing motorcycle trip, and using your motorcycle for everyday commutes to work. Plus, a motorcycle with a perfectly functional battery is a huge bonus when putting your two-wheeler up for sale. Therefore, whether it is for your safety, satisfying ride quality, or resale value, maintaining your battery offers a profitable deal in all aspects.

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