Recalibrating laptop batteries

If your laptop battery is older or reporting incorrectly, it may be possible to recalibrate the battery. This can correct the reported capacity or battery gauge to extend the life of the battery.

IMPORTANT: Recalibration only corrects the capacity on worn out batteries. There is no way to reverse the aging process.

For help understanding what calibration is, why it’s important, and how to calibrate batteries in other types of devices, check out the Battery Calibration Wiki.

Guide notes

• If your battery exceeds 30-40 °C (86-104 °F), REPLACE THE BATTERY!
• You will likely see a capacity decrease. This is good – not bad.
• Try to avoid using the laptop while it is charging. This may affect the calibration.
• Inconsistent reporting may indicate an EOL battery. Proper care delays this, but it cannot be avoided or reversed.
• If your battery is older, consider a ~10% discharge. A full discharge may kill the battery.

How to recalibrate the battery

• Charge the laptop to 100%. Use it until it shuts down and no longer turns on.
  • See BIOS lockouts and EOL quirks for HP and Lenovo laptops.
• Immediately recharge the battery. Do not use the laptop if possible.

BIOS lockouts and EOL quirks

• (BIOS lockout) HP laptops have a 15% BIOS lockout and need to be bypassed for a full discharge. Immediately charge the battery once the laptop shuts off.
  • All HP and most Compaq laptops.
• (BIOS lockout) Some Lenovo laptops have a 7% critical capacity lockout (0190).
  • Only occurs if the laptop shuts off early. Easily bypassed.
• (EOL quirk) Some Dell batteries hold incorrect data once the battery is heavily worn, or end of life. This issue self corrects with time. I have seen this on a few OEM Dell batteries. Notably, the NX31D (DOM unknown/2x with same issue) 65Wh (2014 DOM/E6440) and a RMJFW 65Wh Extended (2014 DOM/E6220). The 45Wh 34GKR is prone to it, but to a lesser degree (2014 DOM/E7440).
• (Firmware quirk) Some laptops like to show 0% wear in BatteryInfoView – notably most HP models. In order to access the data with HP, you must run the diagnostics (UEFI may be required), or use the HP Support Assistant battery check and find the advanced info. This is not a hardware fault, but a quirk with HP.