How Long Do Lithium-Ion Batteries Last?
Battery-powered tools have come a long way in the last decade. Moving to lithium-ion as an energy storage medium, instead of the older nickel-cadmium batteries, improves performance and runtimes to a point that “cutting the cord” has become a viable option for many professional applications. Pros can now do away with lugging around extension cords and generators to the job site. However, because Li-Ion batteries are expensive, the move to cordless convenience can prove to be an investment. Naturally, before jumping into a cordless tool line, the discerning Pro will consider how big an investment cordlessness requires in the long-term. How long can a battery sit unused? How many charging cycles can you expect from a battery? What’s different about Li-Ion batteries? How long do lithium-ion batteries last?
We talked to our friends at Bosch, DeWalt, Hitachi, Makita, Milwaukee, and Ridgid get some answers straight from the manufacturers. While the answers vary here and there, there’s a general consensus on the major points.
How Long Do Lithium-Ion Batteries Last In Storage?
There are also a number of external factors that affect a battery pack’s lifespan on the shelf. What was the state of the pack’s charge when it was stored? Will the user store the battery in hotter or colder temperatures? Will it be stored on the tool, on the shelf, or on the charger? Who made the internal electronics, and how well do those electronics control the current within the pack?
Of course, if a battery pack drops below a certain charge capacity, the pack will cease charging at all, thus meeting the end of its usable life. The time it takes for this to occur depends, again, on manufacturing processes and components as well as those external factors.
All of that having been said, there seems to be a consensus about what you can generally expect from a battery pack’s shelf life. If you take care to store your batteries correctly, you can expect your batteries to last anywhere between 3 – 6 years on a shelf. Of course, you’ll want to keep your batteries out of the heat, as extreme heat is the biggest enemy to Li-Ion batteries.
How Many Charging Cycles Can We Expect To Get?
Again, the answer to this question will largely depend on a number of variables. Battery configuration and capacity will play a part, as will ambient storage temperatures.
User behavior will also affect how many charging cycles a battery can go through before it craps out. Believe it or not, you really shouldn’t use your battery packs in place of a hammer. Blunt force trauma will adversely affect the lifespan of your Li-Ion batteries.
So, in terms of charging cycles, how long do Lithium-ion batteries last? Despite the aforementioned variables, most of our manufactures claim that users should expect to get over 1,000 charge cycles out of any given battery.
Of course, we wonder how they define what a charging cycle is? Typically, one charging cycle equals running a battery down and charging it up again. However, most batteries will count one full charging cycle every time you throw your battery on the charger, regardless of how much charge the battery actually needed.
Makita tells us that they use a “smart” system that accounts for this. Their chargers and batteries use a communication system that recognizes a battery’s current charge level and temperature. Then, the charger regulates the optimal current, voltage, and temperature to recharge the battery. This process will extend the life of the battery, as well as the amount of charging cycles the battery can go through. That’s just one example of why you should stick with manufacturer’s original batteries and chargers.
How Long Do Lithium-Ion Batteries Last Compared To NiCad Batteries?
There are a few notable differences between Li-Ion and NiCad. As far as storage mediums go, Li-Ion batteries have less of an environmental impact. Because Li-Ion has the superior energy density, a comparable NiCad battery will be larger and heavier. From a functional standpoint, Li-Ion also doesn’t experience voltage drops as it depletes.
Both varieties of battery will self-discharge in storage. NiCad self-discharges at a rate of about 1-3% per day. So, it won’t be uncommon for an unused battery to still require a recharge every four days if you need to work with a full battery. Li-Ion batteries self-discharge much more slowly. Again, the rate at which this happens will largely revolve around the quality of the pack design and the components used.
Even still, Li-Ion batteries have a lot more technology at work than NiCad batteries ever did, so the comparison seems a little unfair. Some Li-ion battery manufacturers employ overload protection, over-discharge protection, and overheating protection. All of these technologies protect the battery, extending the expected life cycle. NiCad batteries typically won’t have these types of protections in place.
So, while a NiCad battery is expected to last through 1000 charging cycles as well, you’ll have to charge it much more often and deal with the dreaded “battery memory”.
The Bottom Line
So, how long do Lithium-ion batteries last? To sum it all up, the bare minimum that most manufacturers expect from their batteries is around 3 years or 1,000 charging cycles. Bosch, DeWalt, Hitachi, Makita, Milwaukee, and Ridgid all warranty their Lithium-ion batteries for 3 years. Of course, if you take care of your batteries, there’s no reason not to expect them to last longer.