Although the three-year-old drill doesn't have any obligation to you, you'll still want to know how much of its battery life remains. All questions regarding battery life can be settled by referring to two clocks, one of which keeps going even when the battery is in a drawer.
The figure published as the standard is two to three years, or 300 to 500 complete charge cycles, whichever occurs first; higher-quality packs go beyond this figure while bad habits cause it to be reduced, but that is the realistic baseline against which to plan.
The guide provides the actual figures regarding how long power tool batteries last: the official figure, what the various manufacturers actually publish as opposed to what is commonly repeated online, why a battery still deteriorates even if it is not in use, the habits which reduce the lifespan, and the four habits that extend it. More information on batteries is available in our electric tool battery guide.
The baseline: 300 to 500 cycles, or 2 to 3 years
The support materials provided by Black & Decker give the usual figure as being that a lithium-ion battery lasts for about two to three years or for 300 to 500 full charge cycles, whichever occurs first.
A complete cycle doesn't consist simply of a trip to the charger; it involves starting with a full charge, using it until it's empty, and then charging it up again. Five top-ups of twenty percent each amount to about one full cycle, and this is important since it means that occasional users reach the calendar limit before they reach the cycle limit.
What brands actually publish
That's where the internet shows a lack of care, and you ought to be aware of it before you rely on a table.
Most brands do not give a single figure for the number of charge cycles their batteries can handle. The support departments for Black & Decker and DeWalt use a figure in the 300 to 500 range. Husqvarna is one of the few companies that provides specific numbers: in its catalogue it states that its standard batteries are good for about 400 recharges and its professional BLi300 pack for about 1,500. This is the range that is published, from 400 to 1,500, according to how much the battery cost.
The figures you encounter for other brands—such as a neat 1,000 cycles for one particular red-brand product or 3,000 for a chainsaw brand—are generally media estimates and have no official source to back them. They may be about right, but since they are not officially published, don't base your budget on them. The truthful general rule in the industry is that a well-made pack should last between 500 and 1,000 cycles, and you should regard that figure as a benchmark only, not as a warranty.
| Number | Status |
|---|---|
| 300 to 500 cycles, 2 to 3 years | Published by Black & Decker and DeWalt support |
| Up to 400 standard, up to 1,500 pro pack | Published in Husqvarna's catalog |
| 1,000 plus for premium brands | Common media estimate, no official page |
| 500 to 1,000 | General industry benchmark, not a warranty |
Whichever comes first: cycles vs calendar
The clause saying "whichever comes first" carries out more tasks than the numbers.
Here's how it plays out at three usage levels:
| How you use it | What hits first | Rough expectation |
|---|---|---|
| Daily, all day | The cycle count | 300 to 500 cycles can arrive inside a year or two |
| Weekends and projects | The calendar | The pack turns two or three years old long before 500 cycles |
| Sits in a drawer | The calendar, silently | A two-year-old unused pack has aged as much as a used one |
A battery that has never been used doesn't retain its youthful condition since the cells age chemically regardless of whether they are cycled or not; that is the reason why a pack which had been barely used three years ago is still a three-year-old pack. The sticker on the shelf has no effect on the passage of time.
What shortens the number
The main cause of the damage comes from four habits, and all of them can be corrected at no cost.
- Running packs to zero. Deep discharge stresses the cells. Top up instead.
- Heat. Hot garages, parked cars, direct sun. Heat is the quiet killer of lithium packs.
- Charging a hot pack. Give it half an hour to cool after hard use.
- Storing full or empty. Both extremes age cells faster than the middle.
On the other hand, there are four habits to follow when storing them: keep the packs at about half charge when storing them, keep them cool and dry and out of reach of anything flammable, since this is also the Power Tool Institute's standard advice, unplug the charger once charging is complete, and don't purchase a capacity greater than you actually need, since it is the pack you use that will last. For a more detailed look at the full storage routine, see our guide on how to store power tool batteries.
When the number is up
You'll notice the usual symptoms when the pack reaches its capacity: a shorter running time per charge, having to connect it to the charger more frequently, and it stopping when under load. If you'd like to see the full list of symptoms and a test you can carry out to tell whether a battery is failing, then the guide on a power tool battery that isn't charging covers that particular section.
Here's one more straightforward note: whether the pack is original or compatible, replacing it will restore the full run time. Once the current battery is used up, you can view the different replacement batteries by brand for the twelve platforms that we carry.
Common questions about battery lifespan
How long do power tool batteries last?
Two to three years, or 300 to 500 full charge cycles, whichever comes first, per the published support figures. Premium packs can stretch further, and hard use shortens it.
How many charge cycles does a power tool battery last?
The published baseline is 300 to 500 full cycles. A full cycle is a complete charge, discharge, and recharge, so partial top-ups add up. Husqvarna publishes up to 1,500 for its professional pack, and the general industry benchmark runs 500 to 1,000.
Do power tool batteries go bad if not used?
Yes. Cells age chemically even in storage, so a pack that sat for two years is still a two-year-old pack. Storing it around half charge, cool and dry, slows the aging, but nothing stops it.
What kills power tool batteries?
Deep discharges, heat, charging a hot pack, and storing packs fully charged or fully empty. The fixes are free: top up instead of draining, keep packs cool, let them rest before charging, and store them around half charge.
How do you know when to replace a battery?
Shorter run time per charge, more trips to the charger, and cutting out under load are the classic signs. If the pack also gets hot or swells, stop using it immediately.
The honest reply to "how long?" is that it will take two to three years, or 300 to 500 full cycles, whichever comes first, and it's the habits that determine whether you end up at one end of the range or the other; you should keep the battery cool, keep it at half charge, and refill it rather than draining it, in which case the next pack will reach the calendar before the cycles, which is the way to lose.
References & Sources
- Black & Decker batteries lifespan support article (Black & Decker support)
- Husqvarna official catalog (battery recharge cycle ratings)
- Power Tool Institute battery safety guidance (Power Tool Institute, the power tool industry's safety association)
Need a replacement?
If the numbers are up, browse replacement batteries by brand. We stock compatible packs for twelve platforms, and any question goes to a real person through our contact page.