# How Long Can a Lithium-Ion Battery Last?
Battery-powered tools have made significant advancements in the past decade. Small handheld power tools have transitioned from using nickel-cadmium batteries to lithium-ion batteries as the energy storage medium. This shift has resulted in improved power, longer runtime, and a significant reduction in weight. Even larger tools like zero-turn lawn mowers and small vehicles are now utilizing lithium-ion batteries instead of traditional gasoline or lead-acid batteries. Regardless of the type of battery-powered tool, the lifespan of lithium-ion batteries remains a top concern for many users.
Table of contents
- How many charge cycles do you expect to get?
- How Charge Cycles Affect Li-Ion Battery Capacity
- How long can lithium-ion batteries be stored?
- Heat kills lithium-ion battery packs
- How long does a lithium-ion battery last compared to a nickel-cadmium battery?
- Beyond Lithium-Ion Lifetime Issues
- Let’s Summarize
How Many Charge Cycles Do You Expect to Get?
When we discuss the lifespan of a Li-ion battery, we are ultimately referring to the number of charge cycles it can endure. However, the number of charge cycles can vary depending on how you charge the battery and what you consider a charge cycle. Do you recharge your batteries at the end of the day? Do you replace them as soon as you finish using the tool, or do you recharge them during lunch breaks to ensure they remain topped up? Additionally, battery configuration, capacity, and ambient storage temperature also play a role in determining the number of charge cycles.
Unfortunately, most manufacturers define a charge cycle as any instance when you put the battery in the charger and allow it to charge fully. Although Li-ion batteries do not suffer from battery memory issues like other types, excessively charging them can still reduce their overall lifespan.
At present, most power tool manufacturers claim that their batteries can endure over 1,000 charge cycles. If you charge the battery pack once a day, that would give you approximately 2.7 years of usage. If you work five days a week, it would equate to roughly 3.8 years. Some manufacturers even claim 2,000 recharges, effectively doubling those numbers.
How Charge Cycles Affect Li-Ion Battery Capacity
While manufacturers may have different definitions of a charge cycle, all batteries gradually degrade in terms of their maximum capacity over time. Every time you cycle/charge the battery, it loses a small portion of its maximum storage capacity. Although this may not noticeably affect performance or uptime, it does impact the overall capacity.
Several studies have demonstrated that battery capacity can diminish by 40% or more after 1,000 cycles. To address this issue, companies like Makita have implemented a “smart” system in their chargers and batteries. This system utilizes communication technology to identify the battery’s current charge level and temperature. The charger then adjusts the current, voltage, and temperature to optimize the charging process, thereby extending the battery’s lifespan and increasing the number of charge cycles it can withstand. This is one reason why it’s advisable to stick with the original battery and charger.
How Long Can Lithium-Ion Batteries Be Stored?
Apart from examining how long Li-ion batteries can last, it’s essential to consider their storage capabilities. This aspect is particularly relevant when deciding whether to purchase used batteries from flea markets.
Many factors can influence the lifespan of a battery pack when left on the shelf. To ensure the best results, it is generally recommended to store the battery at around 50% charge if you don’t plan to use it for a week or so. Though slight variations may exist among manufacturers, this level minimizes the degradation of the battery’s storage capacity.
Additionally, periodic checks on the battery packs are necessary as they may experience slight drainage. Maintaining the charge level recommended by the manufacturer, typically around 50%, ensures that the pack is not completely depleted. By following these practices, batteries can be stored for up to 3-5 years.
Heat Kills Lithium-Ion Battery Packs
Storing batteries in a cool and dry place is crucial. Avoid exposing them to excessive heat, as it can significantly shorten their lifespan. It’s important to refrain from topping off the battery on hot summer days or storing them in hot sheds. Instead, find a location like your garage where the temperature can be regulated to maintain a lower battery pack temperature.
High temperatures can be detrimental to Li-ion batteries. To minimize the number of cycles, store the battery pack in a hot environment with a full charge.
If the battery pack falls below a specific charge capacity, it may not accept a charge. The charger may not recognize it as a viable candidate for recharging. In this case, the battery is considered at the end of its life (though it’s worth noting that some dead batteries can be revived).
Editor’s note: Check out these lithium-ion battery charging tips for our recommendations on maximizing battery life and runtime.
How Long Does a Lithium-Ion Battery Last Compared to a Nickel-Cadmium Battery?
Although nickel-cadmium (NiCad) batteries have become outdated, they still serve as a benchmark for comparison in some people’s minds. Li-ion batteries, being smaller and lighter due to their higher energy density, outperform NiCad batteries. Unlike NiCad batteries, Li-ion batteries do not experience a voltage drop when depleted. Their shelf life also surpasses that of NiCad batteries.
NiCad batteries self-discharge at a rate of about 1-3% per day, necessitating regular charging even if they are not used. On the other hand, Li-ion batteries self-discharge at a much slower rate, almost imperceptibly. The extent of discharge depends on the quality of the battery pack design.
Lithium-ion batteries also enjoy a wide range of advanced technologies for overload, over-discharge, and over-temperature protection. These functionalities protect the battery and extend its expected lifecycle. In contrast, NiCad and NiMH batteries typically lack such protections.
Editor’s note: Check out these lithium-ion battery maintenance tips to keep your battery healthy in the long run.
Going Beyond the Lithium-Ion Longevity Question
Determining how long a Li-ion battery can last often involves considering replacement and ongoing costs. After all, lithium-ion batteries are more expensive than lead-acid or nickel-cadmium batteries. Furthermore, they are considerably pricier than a can of gasoline!
Therefore, while transitioning to the convenience of wireless tools requires a significant initial investment, it is essential to consider the eventual cost of replacement. Professionals must carefully evaluate the long-term implications of adopting a cordless tool lineup.
Other questions to address include the price of replacement battery packs and the potential fuel and maintenance savings for larger equipment compared to battery replacement costs. By answering these complex questions, we gain a comprehensive understanding of the entire picture surrounding how long lithium-ion batteries last.
So, how long can a lithium-ion battery last? Most manufacturers typically offer warranties of 2-3 years for their lithium-ion batteries, indicating their minimum expectations for these products. Some even provide warranties lasting up to 4 years. As technology continues to advance and reliability improves, we can expect more companies to extend these warranties.
If you take proper care of your batteries, there’s no reason not to expect them to last at least as long as these warranty periods, if not longer.