I own a Lenovo Y500 series laptop. The battery being an year old lasts only 1 hour. But the strange thing is that, when the charge comes down to 25-20 it drops to 6%(critical battery level) in a moment.

Please suggest some solution (other than replacing the battery).

P.S. : I do many battery saving things already, like lowering brightness, switching to power-saver mode, turning off 'aero' on windows, etc.

  • Here is a similar question. Might provide more insight. – SgtOJ Nov 28 '10 at 20:49
  • My doctor told me the best thing for my health is if I stop drinking to excess, stop eating junk food every day, exercise at least occasionally, lose 50 pounds, and quit smoking. So I asked him what the second best thing would be. – David Schwartz Feb 26 '16 at 20:59

Sorry to say it, but I don't think there's another answer to be had; what you are experiencing is usual for a battery that needs replacing.

Their expected life-span is only about 1 year (according to the manufacturers).

The reason the readings act weird is because when the battery becomes old and faulty it can't properly gauge the total capacity or current charge, so the gauge readings are based on inaccurate numbers.

  • I've seen this exact behavior with my Dell Latitude - the original battery would go find until it hit about 45%, then die in about 60 seconds. Basically it means your battery is shot and you need a new one. – Michael Kohne Jun 22 '10 at 15:48
  • I've had multiple batteries die this way. I believe it is an indication that one of your battery cells is actually dead. – SysAdmin1138 Jun 22 '10 at 16:12
  • Thanx guys :) I better get a new battery. – Karan Jun 23 '10 at 13:18
  • @Ƭᴇcʜιᴇ007 , expected life is 1 year? Isn't it 3? – Pacerier Jan 19 '15 at 3:15

There is some problem with the Lenovo Battery/UEFI Firmware. The Battery Manager on Window or tp_sampi module under linux is usually configured to extend the batteries life by only charging it to 85%.

But discharging the battery from 85% (eventually somehow related to hibernate) can cause the batteries charge counter to drift off more and more over time. The result is a sudden drop of battery life at some point (in my case, at around 45% it suddenly drops tp 6%). The battery reports 85% way too early.

People reported that setting the thresholds to 100% mostly resolved the problem after a few full charge cycles.


I know this is an old issue, but I've had the problem myself and the solution was to charge it fully, then leave it plugged in at 100% for about 2-3 days. After that, it discharged normally without any sudden % drops.

The issue I was having with Arch linux using TLP's battery re-calibration: the battery percentage would suddenly drop from around 60% down to 6% during the re-calibration itself. I didn't try discharging it normally, previously. The problem occurred after an extended period of leaving the laptop plugged in at around 50% capacity.

I've reset the charge thresholds on my Thinkpad now, and I'm going to observe how it works. If the problem re-appears, I can simply re-calibrate it the same way again.


I had same issue as yours. I posted question saying that notification is not showing up in Windows7. After posting the question here, I did try to find the problem and I found that even my battery life jumps same as yours from 25%-6%. After looking at your question, even I thought my laptop battery life is over. But, somehow I wanted to retest it again by changing some settings in the Balanced power mode and surprisingly it started working fine after changing couple of settings. If you look at my question Brian suggested some finding on net about this issue, so I tried to modify settings to get the notification after that it never jumped from 25%-6% again. Now, my laptop is working fine and notifying me when it reaches 10% and hibernates when it is at 5%.

As the answers you got from techie007 and others I'm not sure whether they should be accepted as is. I'm saying this because as soon as I shifted from XP to Windows 7 this problem started. I was bit lazy in finding the problem so I let it go for a month or so without investigating. But yesterday when put up a question all these findings have come out. Since then I was continuously testing my battery with full charge to completely dry out, it never jumped again. I'm not sure about your case, but in my case above answers doesn't apply to me and it might be a bug in the Windows7 OS. May be to get more clarity I need to switch back to XP, but I cant to do that at this moment.

One more addition to this reasoning is I've got 3 same laptops bought at the same time and all are having XP on them, they are still working fine only my laptop got this issue by switching to Windows 7.

May be I can check this by switching other laptop to Windows 7 in couple of weeks. I'll update it after that. Hope it works well.

  • @karan: I tried with other laptop as well and I found that its a problem with Windows7. So, I'm sure even your problem should be solved. – JayaprakashReddy Dec 7 '10 at 6:06

You could check your computer's documentation to see if it mentions anywhere battery calibration.

How often did you let the battery drain all the way? Since you said it's 1 year old, there is a good chance that it's lithium-ion battery, and you shouldn't let them go below 20% charge because if you do, they will wear out much faster than they normally do.

Just as techie007 said, the battery need to be replaced


I know that this is an old question. But I wanted to answer to this question because I disagree to many of the answers here. Although there is a chance that battery life has ended, it is mostly because of something else.

I also had the same problem. TLP was the culprit. It was because of this, the calibration was screwed up. I fixed it by setting the battery threshold to 100% and charging the laptop for about a day. Refer this. Try this before buying a new battery.


As a battery ages, its internal resistance increases which affects battery life under heavy load more than it does under light load. Battery fuel gauges often fail to account for this effect resulting in inaccurate indication of the battery's state of charge.

  • In my experience on my laptop, at higher loads, the battery will drop from higher percentage levels down to about 7%. However, under lighter loads, the battery might get to 15-20% before it abruptly drops the percentage.

  • The reason for this is internal resistance. As batteries age, their internal resistance rises. While this affects battery life at all load levels, it affects heavier loads more than it does lighter loads. A new battery may be able to deliver 6 hours of operation under a particular light load and 3 hours under a particular heavy load. An old battery might be able to deliver 5 hours of operation under the same light load, but 90 minutes or less under the same heavy load.

  • Battery fuel gauges tend to assume that the remaining battery life and the amount of power drawn from them are inversely proportional. However, because internal resistance causes disproportionately more energy to be wasted as heat with heavier loads, this assumption fails to hold when the underlying cells have aged and the battery is under load. As a result, the battery reports that it has more power than it really does, then abruptly drops the reported state of charge when it realizes that it does not really have that much battery life left.

  • To monitor the status of the battery, you can use the free BatteryInfoView software. Most laptop batteries report their designed and current full charge capacities, which indicate the degree to which the battery has degraded. You may want to replace the battery if it holds less than 60% of its original capacity; heavily-aged batteries are more likely to completely fail and stop accepting charges altogether.


undercharging the battery then setting the threshold to 100% for couple of days worked for me. now i've put it back to 90% and I'll see if the sudden drop the charge will reappear again.

  • Welcome to Super User. The site tries to avoid duplication, so the intention is that each answer should provide a solution to the question that is substantially different from what has already been contributed. This duplicates information that has already been provided. – fixer1234 Nov 13 '16 at 17:11

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