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I do NOT mean battery "life" which is how long a battery holds charge. Battery life is usually like 12-24 hours. The word I'm seeking refers to the time you can use the battery daily until it fails to hold a charge or there is a serious drop-off, so like 12-24 months. After that point, while you may be able to recharge it to 100%, that 100% doesn't generate many hours of use.

For instance: "My current phone battery's life is at 50% which means there are roughly 6 hours left of life in the battery. When I bought my battery a year ago, that same 50% meant 12 hours left because my battery's ability to hold charge had not yet degraded. In another 2 years it will be unable to hold any charge for more than 30 minutes, rendering it useless. My phone has a battery with poor _________."

Is there a name for that curve of declining ability for a battery to hold charge with frequent use?

Longevity and lifespan are too confusing and are already used as synonyms for battery life which made my searching efforts fruitless. I will accept a compound word or phrase. PS: I'm pretty sure Big Battery doesn't want people to have a word for this because being unable to specify batteries with good __________ means we have to buy new phones more regularly.

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9 Answers 9

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You may not like longevity or lifespan, but these are the terms used in the technical world. For example, here is how cleantechnica defines longevity:

Longevity refers to the number of charge cycles a battery can take before it no longer charges.

And here is what apple.com says about lifespan:

‘Battery life’ is the amount of time your device runs before it needs to be recharged. ‘Battery lifespan’ is the amount of time your battery lasts until it needs to be replaced.

Mastervolt also uses lifespan:

If kept in a charged state when unused, the common lifespan of a 12-volt Gel or AGM battery is up to six years. Higher average temperatures will shorten the lifespan of the battery.

However, you can always use cycle life, which Sciencedirect.com defines as follows:

The cycle life of batteries is the number of charge and discharge cycles that a battery can complete before losing performance.

Mpoweruk also uses it:

Battery Cycle Life is defined as the number of complete charge - discharge cycles a battery can perform before its nominal capacity falls below 80% of its initial rated capacity.

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  • Cycle life offers the most clarity. thank you Apr 11 at 22:58
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    The problem with the word “cycle life” is that batteries age even when they rarely go through a discharge+recharge cycle.
    – Michael
    Apr 12 at 6:01
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    To complement "cycle life", there is also "shelf life" which is how long something lasts when sitting unused.
    – David
    Apr 12 at 14:28
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    @David I'm surprised there is only one mention of "shelf life" in this page. It seems to be very relevant to the question.
    – justhalf
    Apr 14 at 7:33
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    @AustinCapobianco: Non-rechargeable batteries actually have expiry dates (based on assumptions regarding temperature, resulting self-discharge rate and some arbitrary “enough remaining energy” threshold). With rechargable batteries it becomes a lot more complex. Number of charging cycles, depth of (dis)charge, temperature, currents, age, balancing between cells … I think even mechanical vibrations have an effect.
    – Michael
    Apr 15 at 10:57
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Is there a name for that curve of declining ability for a battery to hold charge with frequent use?

The term battery health and battery wear level are sometimes used by computer programs which provide information about laptop computer batteries. A battery with its capacity reduced from 10,000 mAh to 8,000 mAh would have a battery health of 80% and a wear level of 20%. An example program running under Windows is batteryinfoview.

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  • Yeah, this is a good one. You might also see "percentage of design capacity" although this obviously wouldn't work in OP's example sentence. Apr 13 at 22:26
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One rather cumbersome word is rechargeability — the ability to be recharged.

It's appeared in at least one article, from the University of New South Wales, and in the scholarly article from Advanced Materials which it quotes.

...severely restrict zinc anode's and thus AZB's rechargeability (lifetime).

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  • The issue with this is it doesn't explicitly reference a time interval. When comparing batteries, the main relevant metrics are how long its life and cycle life are. Saying a battery has 20 rechargebility is a lot harder to parse than that it has a 20 month cycle life Apr 15 at 9:19
  • @AustinCapobianco Your examples don't have any sense of measuring rechargeability, merely what that quantity is called.
    – Andrew Leach
    Apr 15 at 9:59
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Durability

the quality of being able to last a long time without becoming damaged

Also described on Wikipedia as:

Durability is the ability of a physical product to remain functional, without requiring excessive maintenance or repair, when faced with the challenges of normal operation over its design lifetime.  There are several measures of durability in use, including years of life, hours of use, and number of operational cycles.

And in the off chance you may be interested by a more technical expression, it seems technical documents refer to it as battery cycling performance (this is a link to Battery University, which is one of the many websites I find online by searching these keywords), as a reference to how much charge it can hold, after how many cycle of use (1 full recharge/discharge is equal to 1 cycle; using only 50% of battery capacity before recharging is equal to 0.5 cycle).

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    No, even if some people use durability to refer to cycle life (which I haven't seen much evidence of) it's too easily conflated with the battery's resistance to damage. You really have to stretch the definition of durability to make it fit in this context. The problem with battery cycling performance, although technically correct, is it doesn't explicitly refer to a time interval. It's the same reason we tend to use the metric of battery life rather than battery performance. Apr 15 at 9:15
  • @AustinCapobianco That is literally what it is though. The more you use the battery, the more damaged it becomes. And if you strain it a lot by overdischarging it and using fast charging, it will get damaged a lot faster. A battery will last longer if you don't strain it, much like anything. I have had the same phone for several years and the battery is lasting for 3 weeks without recharging. The reason the battery of your phone seems to last only 1 year is because of a very intensive use. What you think is a "time interval" is just how much you can use it before it dies. And you use it a lot.
    – Clockwork
    Apr 15 at 9:54
  • Then again, if what you intend to do is to keep it simple for a conversation, then yes, talking about a "limited time of use" would be fair, I guess.
    – Clockwork
    Apr 15 at 10:00
  • I get that it's reducing the functionality of the battery, but when most people hear durability they think of the ability not break, rather than the ability to continue functioning like it was new for a long time. Also durability is already used in a very similar context to refer to the resistance to damage in the phone itself. It just isn't practical to use durability (or lifespan or longevity) when other words are available because of that ambiguity. I mainly needed this word as I was looking for a new phone to buy. Apr 15 at 10:25
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The alternative the OP is looking for is

"Service life"

(I found that instantly by googling "is there an alternate term for battery longevity?" ... :) )

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  • Was it like some random quora post? I just tried googling that phrase and that's all that came up for me Apr 15 at 9:25
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Is there a name for that curve of declining ability for a battery to hold charge with frequent use?

No, because the result depends on several extrinsic factors besides the battery itself. Such a curve would be application specific and environment specific. But those exist, of course. For instance, light rail commuter cars may be battery driven over part of their run and recharged via catenary or center rails for part of the run. The performance can be very accurately predicted as an entire system, but it isn't a battery characteristic per say. The battery characteristic is a many-dimensional plot that you have to pick a trajectory from that represents what you are doing with the battery. The battery string's series and parallel arrangement affects the performance. Charging sequences are often more important than load sequences. The form factors of the cells are important. So you need to think of this as the system's performance, of which the battery is only one part, and realize the battery can't do much about many of the important factors that are driving the lifespan you experience.

For example, if you begin to recharge a lead acid storage battery immediately (milliseconds) after removing the load you can often get 20% longer lifespan to 80% capacity compared to waiting 5 minutes before beginning recharge. The published lifespans are going to be based on that millisecond recharge.

Here's a link to NREL's battery lifespan research unit. It will give you a good primer on the engineering lingo - https://www.nrel.gov/transportation/battery-lifespan.html

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  • It looks like this is more of a technical answer but I still upvoted it for its usefulness in better understanding how it works.
    – Clockwork
    Apr 12 at 7:25
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I believe the term you are looking for is 'useful life', used in economic and financial documents to estimate the number of years an asset is likely to remain in service.

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  • I wonder what the non-useful life entails? Apr 14 at 14:09
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charge cycle

A charge cycle happens when you use all of the battery’s power – but that doesn’t necessarily mean in a single charge.

Apple Support

For example, you could use half of your laptop’s charge in one day, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two. What about the number of charge cycles from empty to full a battery can handle ?

You can charge a battery ten times a week, put it away for a year and then continue to use up the charges the battery can provide.

The use of the battery also determines its performance.

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  • Ofcourse if the battery is 50 percent empty and you charge it up you did not use up a charge cycle but that is not the point. the point is that time is not a good measure for how long a battery will perform well and charge well.
    – S.A.
    Apr 14 at 16:52
  • I think "cycle life" is just a more efficient way to say "the number of charge cycles a battery can go through until it stops holding charge" Apr 15 at 9:08
  • This is how one manufacturer is doing it fenix-store.com/cdn/shop/products/…
    – S.A.
    Apr 15 at 9:13
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IM SORRY ARE YOU REFERING TO THE Common *

Battery Cell Half Life

  • of whatever particular brand you were speaking of ?

You'll have to forgive me if this isn't what you're looking for it's just throughout my journeys I've had to do certain things like water battery cells on forklifts and heavy equipment that ran on battery and that is what we would refer to it as in such situations. Especially since it would usually fluctuate depending on water to acid ratio. I hope that helps

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    – Community Bot
    Apr 13 at 4:10
  • That probably is also technically correct, but I def see "cycle life" in use a lot more than battery cell half life e.g. researchgate.net/figure/… Apr 15 at 9:06

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