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The critical level of my battery is 7%. But recently, the laptop shuts down at 17% although I have set to hibernate from the Power options when the battery reaches 7%. Any ideas?

  • So it used to work as expected at 7% previously? How old is the battery? Have you checked with your notebook's manufacturer for a battery calibration utility? – Ƭᴇcʜιᴇ007 Sep 27 '17 at 16:26
  • Sometimes Windows updates turn Hibernate off. You can check in the power options dilaog. To turn it on from Admin CMD prompt: powercfg /h on – DrMoishe Pippik Sep 27 '17 at 16:30
  • @Ƭᴇcʜιᴇ007 Yes, it used to work as expected at 7% previously. The battery is about 7-8 years old. I have not checked with my notebook's manufacturer HP for a battery calibration utility. I found it from here (support.hp.com/us-en/document/c04700771) and I will use it. – Bushido Sep 27 '17 at 18:34
  • @DrMoishePippik I believe it is turned on as I have enabled hibernation from power options additional settings. – Bushido Sep 27 '17 at 18:37
  • I'd say that if the battery is seven or eight years old, it's probably time to replace it and that may be why you're getting weirdness with the discharge percentages. – Ƭᴇcʜιᴇ007 Sep 27 '17 at 19:45
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This is a very common failure mode with "smart" lithium-ion batteries.

Basically, as a battery ages, its internal resistance increases. This means that under load, its voltage drops more. This throws off the battery's fuel gauge. From one of my previous answers (which assumes a battery with three cells in series):

A battery at 11.1V may have about 40% charge when new but the same voltage may indicate a less than 10% SoC on an old battery.

You might be able to calibrate the fuel gauge by discharging the battery fully, then charging it fully again. However, considering how old the battery is, you should consider replacing it.

Your images indicate that this is a PR09 battery, which is now discontinued. You might still be able to find limited supplies of the genuine OEM battery, but they're going to be limited, and third-party replacements may be easier to get. Before you buy a replacement, be sure to check the reviews, since third-party batteries can be less reliable than OEM batteries.

  • Thank you for the answer. I read from the battery that the manufacturing date is July 2012. The message on the battery says that I should replace it with HP SPARE 633809-001. I searched the web and I found that this particular spare number has different capacities and cells. I wonder how to detect what many cells my present battery has and what is the capacity of it? – Bushido Oct 1 '17 at 19:32
  • I think I found some info: upload.ee/image/7515494/5.jpg, but the cell type is still unknown. – Bushido Oct 1 '17 at 19:42
  • @Bushido: The battery data indicates that it has 943 cycles on it, and a capacity of 3964 mAh, a mere 47% of the 8400 mAh design capacity. More critically, the battery failure code is REOOW, which means Replace - Out of Warranty. I'd replace the battery. – bwDraco Oct 1 '17 at 20:20
  • Does your battery specify a model number, like MU09? – bwDraco Oct 1 '17 at 20:26
  • I found a long line that starts with "CT:". Does this might be it? – Bushido Oct 1 '17 at 21:34

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