Do newer laptop batteries still need to be drained before recharging?

Question

10 years ago when I was doing hardware support it was best practice to fully drain a laptop battery prior to recharging in order to maximize its life. Is this still the case or can a battery now be recharged at any point without worrying about shortening the lifespan?

Solution 1

NiCd and Nickel Hydride batteries need occasional deep discharging. Lithium batteries do not suffer from the same issue - and deep discharging can damage them. This article discusses the subject in more depth.

Solution 2

For lithium-ion, it is actually now considered bad practice to completely drain the battery before recharging. NiCd and NiMH batteries need this to be done to minimize their so called "memory effect" - not so for Lithium Ion. In fact, it will actually be harmful for Li-Ion batteries.

I quote you this paragraph from this link

A lithium-ion battery provides 300-500 discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible. Instead, charge the battery more often or use a larger battery. There is no concern of memory when applying unscheduled charges.

There are many other sources online that support this statement, but I know this from my long-time exposure to battery conditioning due to certain hobbies (e.g flashlights).

From Wikipedia's entry of Lithium Ion batteries :

Lithium-ion batteries should never be depleted below their minimum voltage (2.4 to 2.8 V/cell, depending on chemistry). If a lithium-ion battery is stored with too low a charge, there is a risk that the charge will drop below the low-voltage threshold, resulting in an unrecoverable dead battery.

Solution 3

Lithium ions seem to have different issues, more to do with how far you drain them and how you store them http://en.wikipedia.org/wiki/Liion#Guidelines_for_prolonging_lithium-ion_battery_life

Solution 4

I believe there's not really "battery memory" anymore with modern batteries, but it's a good idea to run down completely one time from a full charge to calibrate the "remaining time" left on most laptops. I've done this on both Mac and Windows laptops and it helps.

Solution 5

Nope, although every 10-20 charges, it is best to in order to calibrate your battery (otherwise you may see it saying 2 hours left and then going flat after 20 minutes!)

You are referring to the "memory effect". Typically, Lithium Ion batteries (most modern gadgets use these) do not get affected by this.

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Comments

[AnC]

This might be relevant as well: lifehacker.com.au/2009/10/…

[Jamie Hanrahan]

batteryuniversity.com is not a reliable source.

[Jamie Hanrahan]

@DragonLord There is no such "university", so just to start, the site is using lies to gain a false veneer of credibility. Consensus on WP is that BU is not reliable, that BU seems to simply search the net (incl. poor sources like blogs, forums, etc.) for "info" about batteries and regurgitate it without checking. Two EEs actually ran a "sting" and caught BU at it. See for ex. en.wikipedia.org/wiki/… and en.wikipedia.org/wiki/Talk:Lithium-ion_battery/…

[Jamie Hanrahan]

Also en.wikipedia.org/wiki/… .

[bwDraco]

@JamieHanrahan: Downvoted answer. Thanks for the heads-up.

[bwDraco]

Although this may answer the question, you should give a more detailed description of the linked content and explain how it relates to the question. This will help ensure that this answer remains useful in the event the linked page is removed or goes offline. For more information, see this Meta Stack Exchange post.

[Jamie Hanrahan]

Neither NiMH nor NiCd "need occasional deep discharging". "Memory" in NiCds was never a problem in consumer-sized cells; it showed up only in very large sintered-plate cells where the battery was discharged to withn a % or so of the same point many many times. The cells were recovered and the problem cured NOT by any deep discharge, but by programming the charger to reach what is called "overcharge" at the end of the charge cycle. Consumer NiCds can suffer from "voltage depression", caused by leaving them on a trickle charger for too long. Any modern "smart" charger will avoid this.

[Jamie Hanrahan]

Re Li-ion: it's true that deep discharge can damage them. The packs in your laptop, etc., have an internal "electronic fuse" that will open if they're discharged too far. That is because, should charging be attempted after that point, bad things like fire can happen. So once that "fuse" opens, the battery pack is useless. But: no correctly designed laptop, phone, etc., will allow you to discharge its battery that far. So if you want to "fully discharge" your battery, running the device until forced power-off will accomplish as much of that as you safely can. with no risk to the battery.