Comments on: Unplug Your Laptop Regularly (When In Doubt)

By: svtcobra

svtcobra — Fri, 25 Sep 2009 00:12:38 +0000

I have 3 HP laptops at home that are always plugged in except for the occasional trip out of the house. 2 are used for 6-10 hours a day. The third is turned on and used about once every 10 days and used for about an hour. They all have 6 cell batteries, all 18 to 24 months old. Using advice I received from an HP level 2 tech, I leave the batteries out all the time (when plugged in) and only insert the batteries once a month, at which time I switch to battery power and run them all down to 2%, and then fully recharge them. All 3 of the batteries are still running at 80 to 85 percent of their ‘new’ capacity, based on how long the machine actually runs before neeeding recharging. This compares with my previous HP laptops’ batteries that were left in the laptops all the time and were essentially useless by the time they were 24 months old. Just my 2 cents worth on my personal experience.

By: Jeff Harbert

Jeff Harbert — Tue, 22 Sep 2009 16:53:53 +0000

Any rechargeable battery, in my experience, must be used pretty regularly or they won’t hold a decent charge. This is true of all the double-A’s I own, my 14.4v Makita, and my laptops. I try to get my laptop battery down to 10% or so at least once a month.

By: Nehal Patel

Nehal Patel — Tue, 22 Sep 2009 15:38:26 +0000

My work laptops have always been continually charged since they are in a docking station all day – I work in a cube and connect 2 monitors, mouse, keyboard. as a result, my battery life eventually dwindles to about 15 minutes which turns my laptop into a workstation.

By: emailtoid.net/i/8b2d5e1c/…

emailtoid.net/i/8b2d5e1c/… — Tue, 22 Sep 2009 15:08:38 +0000

a mod on thinkpads.com forums suggested i let my 9cell drop to ~40%, then recharge. when on the dock i wait til it drops to 99 or 98%, then unplug, drain to 40% or so, then recharge. after 4 years of ownership and one battery, i’ve still got near full capacity. seems like a good tip for this type of battery.

By: Himanshu Saluja

Himanshu Saluja — Tue, 22 Sep 2009 13:33:21 +0000

I have this Lenovo 3000-Y500 for about 4 years now and it hasn’t shown much decline in battery prowess.

I just make sure its plugged in only when it is on or has less charge.
I unplug it when not in use and full battery.

By: Guillermo Esteves

Guillermo Esteves — Tue, 22 Sep 2009 12:05:58 +0000

I keep my 14-month-old MacBook Pro plugged-in practically 24/7. Now it shuts down without warning at 60% charge (it doesn’t even go to sleep, it just dies) and the battery icon says “Service Battery.”

There’s a chance it’s not related to keeping the laptop plugged-in all the time, but once I replace the battery I won’t be doing it any more.

By: mgseeley

mgseeley — Tue, 22 Sep 2009 11:46:08 +0000

As a point of comparison with Claudio, I regularly unplug my MBP and use my battery down to the reserve power warning before plugging back in. her are my CoconutBattery stats:

Battery-Load Cycles: 695
Age of your Mac: 19 months
Original Battery Capacity: 5600 mAh
Current Battery Capacity: 2433 mAh (43%)

So what does tell us? My battery is half as old as Claudio’s but I cycle it far more frequently. I have more life left in it but should it have more being newer, or less due to heavy cycling?

By: Claudio

Claudio — Tue, 22 Sep 2009 10:52:26 +0000

Look no further than my mac for proof (though more than one data point is usually recommended). Info from the CoconutBattery app:

Battery-Load Cycles: 91
Age of your Mac: 36 months
Original Battery Capacity: 5500 mAh
Current Battery Capacity: 1764 mAh (32%)

By: AJ Robins

AJ Robins — Tue, 22 Sep 2009 07:19:48 +0000

Also, in case it’s not obvious: keeping the laptop plugged in and turned on all the time, keeps the battery warm/hot, which shortens the battery life. If you must keep the laptop plugged in all the time, turn off/suspend/hibernate the laptop.

By: AJ Robins

AJ Robins — Tue, 22 Sep 2009 07:16:59 +0000

Wikipedia (the references, actually) has decent info. To summarize (hopefully, I’ve remembered everything correctly):

* For modern lithium-ion batteries, heat is likely to be the #1 cause of shortened laptop battery life (being next to high-temperature laptop parts is not really good). Heat is a killer; generally, the cooler the battery is kept (but not freezing or below), the longer the useful battery life.

* Lithium-ion batteries like short discharge/charge cycles. Deep discharges aren’t good for the battery.

* However, the battery meter circuitry does generally need a periodic deep discharge for calibration purposes (so that your battery meter reads correctly). Yes, this is at odds at “deep discharges” aren’t good for the battery, but this is an engineering tradeoff: do you want an accurate battery meter or not? In theory, doing it once a month shouldn’t affect the useful lifetime appreciably, which is why the vendors recommend that a deep discharge be done once a month or so.

* Lithium-ion batteries don’t have memory.

* Generally, lithium-ion batteries start degrading from the moment they’re made (due to oxidation, IIRC). Because of this, it may not make sense to buy a spare (to use when the current battery degrades).

* Long-term storage should be with a partial, and not a full charge.