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Battery Calibration Wiki.<\/a><\/p>\n\n<div class=\"clearer\"><\/div><div class=\"headerContainer\"><h3 id=\"Section__Guide_notes\" class=\"header\"><ins>Guide notes<\/ins><\/h3><\/div>\n\n<ul><li><strong><em>If your battery exceeds 30-40 \u00b0C (86-104 \u00b0F), REPLACE THE BATTERY!<\/em><\/strong><\/li><li><strong><em>You will likely see a capacity decrease. This is good - not bad.<\/em><\/strong><\/li><li><strong><em>Try to avoid using the laptop while it is charging. This may affect the calibration.<\/em><\/strong><\/li><li><strong><em>Inconsistent reporting may indicate an EOL battery. Proper care delays this, but it cannot be avoided or reversed.<\/em><\/strong><\/li><li><strong><em>If your battery is older, consider a ~10% discharge. A full discharge may kill the battery.<\/em><\/strong><\/li><\/ul>\n\n<div class=\"clearer\"><\/div><div class=\"headerContainer\"><h3 id=\"Section__How_to_recalibrate_the_battery\" class=\"header\"><ins>How to recalibrate the battery<\/ins><\/h3><\/div>\n\n<ul><li>Charge the laptop to 100%. Use it until it shuts down and no longer turns on.<ul><li>See <strong><em>BIOS lockouts and EOL quirks<\/em><\/strong> for HP and Lenovo laptops.<\/li><\/ul><\/li><li>Immediately recharge the battery. Do not use the laptop if possible.<\/li><\/ul>\n\n<div class=\"clearer\"><\/div><div class=\"headerContainer\"><h3 id=\"Section__BIOS_lockouts_and_EOL_quirks\" class=\"header\"><ins>BIOS lockouts and EOL quirks<\/ins><\/h3><\/div>\n\n<ul><li><strong><em>(BIOS lockout) HP laptops have a 15% BIOS lockout and need to be bypassed for a full discharge.<\/em><\/strong> Immediately charge the battery once the laptop shuts off.<ul><li><strong><em>All HP and most Compaq laptops.<\/em><\/strong><\/li><\/ul><\/li><li><strong><em>(BIOS lockout)<\/em><\/strong> Some Lenovo laptops have a 7% critical capacity lockout (0190).<ul><li><strong><em>Only occurs if the laptop shuts off early. Easily bypassed.<\/em><\/strong><\/li><\/ul><\/li><li><strong><em>(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).<\/em><\/strong><\/li><li><strong><em>(Firmware quirk) Some laptops will show 0% wear in BatteryInfoView - notably HP models. In order to access the data with HP, you must run the diagnostics (UEFI required if yours needs this). In some cases it can be found in the HP Support Assistant app by doing a battery check under the advanced info. This comes down to how HP encodes the battery data and how it is accessed and not a hardware fault.<\/em><\/strong><\/li><\/ul>"},"subscribed":false,"isFavorite":false,"favoriteCount":5,"isCompleted":false,"completedCount":20,"shopifyStore":{"country":"US","currencyCode":"USD","language":"EN","storeCode":"us","shopDomain":"ifixit-us.myshopify.com","storefrontAccessToken":"db3099692534a56ecec7b974a329d302"},"guideData":{"title":"Recalibrating laptop batteries - READ FOR HP MACHINES","mainImage":"https:\/\/guide-images.cdn.ifixit.com\/igi\/fttGWOuDD1wIKJiE.140x105","mainImageUrl2x":"https:\/\/guide-images.cdn.ifixit.com\/igi\/fttGWOuDD1wIKJiE.200x150","mainImageUrlFull":"https:\/\/guide-images.cdn.ifixit.com\/igi\/fttGWOuDD1wIKJiE.large","published_date":"Dec 17, 2017","modified_date":"Jun 14, 2025","isTeardown":false,"guideCommentCount":7,"stepCommentCount":3,"viewCounts":{"today":33,"week":219,"month":1079,"all":218146},"author":{"url":"https:\/\/www.ifixit.com\/User\/76599\/Nick","name":"Nick","image":"https:\/\/guide-images.cdn.ifixit.com\/igi\/vCZUoM4NTJy4NeEq.thumbnail","authorCount":7,"historyUrl":"\/Guide\/history\/101517"},"difficulty":2,"difficultyName":"Easy","timeRequired":"12 hours - 1 day","flags":[{"flagid":"GUIDE_USER_CONTRIBUTED","title":"Community-Contributed Guide","text":"An awesome member of our community made this guide. It was not created by iFixit staff.","privilegeid":1,"icon":"user"}],"mainImageWidth":"140","mainImageHeight":"105","totalTimeIso":"PT86400S","stepCount":11}}">

Recalibrating laptop batteries - READ FOR HP MACHINES

Introduction

IMPORTANT: HP LAPTOPS CAN BE CALIBRATED USING THIS METHOD, BUT IT IS NOT THE RECOMMENDED METHOD FOR "UEFI" HP LAPTOPS - THESE SHOULD BE CALIBRATED WITH THE HP UEFI diagnostic tool IF POSSIBLE. This method works in lieu of using the HP tool, but the FCC must be checked with the UEFI tool as the batteries do not show the health accurately in Windows.

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 will show 0% wear in BatteryInfoView - notably HP models. In order to access the data with HP, you must run the diagnostics (UEFI required if yours needs this). In some cases it can be found in the HP Support Assistant app by doing a battery check under the advanced info. This comes down to how HP encodes the battery data and how it is accessed and not a hardware fault.

What you need

  1. Recalibrating laptop batteries - READ FOR HP MACHINES, Log the original calibration data: step 1, image 1 of 1
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  2. Recalibrating laptop batteries - READ FOR HP MACHINES, Use your laptop: step 2, image 1 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, Use your laptop: step 2, image 2 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, Use your laptop: step 2, image 3 of 3

    • Any data from this step will be lost. Only plug the laptop in to get the machine started from a BIOS lockout.

    • If you are using a Windows laptop, make sure you turn the laptop back on after the initial shutdown. Windows is designed to shut down when the battery in the laptop reports ~3% remaining capacity. This may require brief use of the power adapter if the laptop does not turn on until the charge is higher or it has AC power.

    • Use your laptop while it is discharging. You will want to do this until the computer shuts down, and if you are using Windows turn it on again until the laptop no longer turns on; this ensures a full discharge.

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  3. Recalibrating laptop batteries - READ FOR HP MACHINES, Plug your laptop in: step 3, image 1 of 2 Recalibrating laptop batteries - READ FOR HP MACHINES, Plug your laptop in: step 3, image 2 of 2

    • While it is safe to use your laptop, the calibration accuracy may be affected.

    • Every laptop has a different charge indicator. When your laptop is fully discharged, plug it in immediately. Fully charge the laptop.

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  4. Recalibrating laptop batteries - READ FOR HP MACHINES, Verify the new calibration data: step 4, image 1 of 1

    • This procedure may "kill" end of life batteries.

    • Once you are finished, check the BMS data. The reported data should be corrected.

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  6. Recalibrating laptop batteries - READ FOR HP MACHINES, (Windows 10/11) Battery health check: step 5, image 1 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (Windows 10/11) Battery health check: step 5, image 2 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (Windows 10/11) Battery health check: step 5, image 3 of 3

    • This may not work if your battery is older, even if it is an OEM pack.

    • Run Command Prompt as an administrator. Enter powercfg /batteryreport.

    • When the report is ready, you will receive a message stating where it is located. Check the data for consistency.

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  7. Recalibrating laptop batteries - READ FOR HP MACHINES, (HP UEFI) 15% lockout bypass: step 6, image 1 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (HP UEFI) 15% lockout bypass: step 6, image 2 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (HP UEFI) 15% lockout bypass: step 6, image 3 of 3

    • Authors' note: The UI is different as this was taken in 2017; the newer HP UEFI diagnostic layout is shown in Step 10. However, the loop until error steps are still accurate.

    • This will fully discharge the battery. HP diagnostics do not check the charge capacity.

    • Plug the laptop in and turn it on; unplug it once it is on. Press ESC and select System Diagnostics.

    • Open the Component tests submenu. Select Memory or Hard Drive.

    • Select Extensive test. Choose Loop until error.

    • When the laptop shuts off, immediately recharge the battery.

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  8. Recalibrating laptop batteries - READ FOR HP MACHINES, (HP Legacy BIOS) 15% lockout bypass: step 7, image 1 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (HP Legacy BIOS) 15% lockout bypass: step 7, image 2 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (HP Legacy BIOS) 15% lockout bypass: step 7, image 3 of 3

    • DO NOT apply these settings to your primary OS. They may damage the battery.

    • Boot the laptop into a live Linux Mint Cinnamon session. Open Settings and make the following changes:

    • Open Power Management. Change When the battery is critically low to Do nothing.

    • Use the laptop until it shuts down. Everything from this session will be lost.

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  9. Recalibrating laptop batteries - READ FOR HP MACHINES, (Lenovo 0190) Critical low battery bypass: step 8, image 1 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (Lenovo 0190) Critical low battery bypass: step 8, image 2 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, (Lenovo 0190) Critical low battery bypass: step 8, image 3 of 3

    • Plug the power adapter into your laptop. Allow POST to finish before unplugging the laptop.

    • Disconnect the laptop once the laptop is booted. Finish discharging the battery.

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  10. Recalibrating laptop batteries - READ FOR HP MACHINES, (Optional) Label the battery: step 9, image 1 of 2 Recalibrating laptop batteries - READ FOR HP MACHINES, (Optional) Label the battery: step 9, image 2 of 2

    • To better track the estimated health of the battery, labeling is recommended.

    • Note the date of the recalibration.

    • Note the original charge capacity (Designed capacity).

    • Note the current capacity of the battery (Full charge capacity).

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  11. Recalibrating laptop batteries - READ FOR HP MACHINES, **HP UEFI ONLY** Checking battery health: step 10, image 1 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, **HP UEFI ONLY** Checking battery health: step 10, image 2 of 3 Recalibrating laptop batteries - READ FOR HP MACHINES, **HP UEFI ONLY** Checking battery health: step 10, image 3 of 3

    • If the HP UEFI diagnostics detect a persistent inaccuracy, a calibration will be recommended - this EliteBook 640 G9 does not need it, so it was not presented to me.

    • In order to check the battery health on HP laptops, you MUST use the UEFI tool as HP hides the actual heath data from the operating system. The tool can be downloaded here and written to a USB drive, or a secondary partition on the laptop - the choice is yours.

    • Run the HP diagnostics and do the following to access the battery test:

    • Locate Power in the diagnostics

    • Click on Battery and select Run once. This will take approx 2-3 minutes.

    • NOT SHOWN HERE Click on Battery details to review the health data.

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  12. Recalibrating laptop batteries - READ FOR HP MACHINES, **HP UEFI ONLY** Checking battery health: step 11, image 1 of 1

    • Click on Battery details and you will see the battery data, as well as the condition.

    • This data will tell you what condition your battery is in. The battery condition will be read in capacity left, as well as the overall health.

    • This data is helpful for gauging the condition of the battery. It provides a cycle count and the battery warranty status data, as logged by the pack in the laptop.

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Nick

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7 Guide Comments

Did not help at all.

I have a Windows tablet, pretty old one - previously it was showing 39% battery wear (it actually was holding for about an hour, battery itself is a bir inflated).

A couple days ago it hard crashed and wear level was reseted to 0%. Now some weird stuff started: turning off when reaching 14% battery charge, screen dimming etc.

Tried this method, and as I said in the beginning - it did not help, still shows 0% wear.

Ослик Иа - Reply Share

Late response, but some laptops and Windows based tablets (notably HP) always show 0% wear in Batteryinfoview. You need to go into the UEFI diagnostics or use use HP Support Assistant and grab it from the advanced data on HP. If it’s Dell, UEFI SupportAssist (newer systems) or ePSA (legacy).

Nothing to worry about, but another quirk like the EOL capacity reporting response on some Dell batteries. Added a note in the quirks section about this.

Nick - Reply Share

I’m curious, can we send command through the I2C interface from the laptop itself to the battery and do some calibration from there? is the built-in BMS has the capability to do that?

putraadriansyah08 - Reply Share

May battery charging shows 39% and it should be always plug in (windows 11) on Asus laptop.

Badri Momeni - Reply Share

hello, my laptop is reporting 36wh battery capacity, but it stops at 0 percent for 1 hour, after 36 is drained. before it was showing 25 wh and after charging cycles it increased to 36wh. it seems to progress slowly, but in your situation, it immediately read correct value

Dimavar123 - Reply Share

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