Battery firmware lockout: Difference between revisions

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==How it works==

When the battery is outside its operating range, such as ~~overcharged,~~ overcharged, overheated, unbalanced(in multi-celled battery packs), the BMS prevents the battery from further usage, limiting damage. However, the BMS should resume normal operation when the battery is back within operating range. Instead, the BMS changes bytes in its memory, leading to a "Permanent Fail (PF)" state, preventing the use of said battery even after reconditioning or repairing.

When the battery is outside its operating range, such as overcharged, overheated, unbalanced(in multi-celled battery packs), the BMS prevents the battery from further usage, limiting damage. However, the BMS should resume normal operation when the battery is back within operating range. Instead, the BMS changes bytes in its memory, leading to a "Permanent Fail (PF)" state, preventing the use of said battery even after reconditioning or repairing.

Documentations from known BMS manufacturers such as Texas Instruments said the device can permanently disable the use of the battery pack in case of a "severe failure"<ref>[https://www.ti.com/lit/ug/sluua43a/sluua43a.pdf? https://www.ti.com/lit/ug/sluua43a/sluua43a.pdf?] ([http://web.archive.org/web/20250604023257/https://www.ti.com/lit/ug/sluua43a/sluua43a.pdf Archived])</ref>. However, users report the battery is "bricked" after scenarios like long-term storage, discharging a laptop overnight or using a power tool in a warm environment while charging it cool, indicating the manufacturers have abused the BMS program, exaggerating the nature of the failure as a form of [[self-destructive design]].

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===Consumer electronics===

[[File:BQ40Z50R3 1.jpg|thumb|A screenshot of a "bricked" battery pack with healthy cells, note the red "PF_EN"]]

[[File:Texas Instruments BQ40Z50R3 1.jpg|thumb|A screenshot of a "bricked" battery pack with healthy cells, note the red "PF_EN"]]

The most common consumer electronics using sophisticated battery management system for their multi-cell battery pack are laptop computers. There are many discussions about the battery "lockout" after replacing or recharging individual cells, indicating battery firmware lockout is the main obstacle of battery repair<ref>{{Cite web |date=2022-10-06 |title=How can I reset the laptop battery BMS? |url=https://electronics.stackexchange.com/questions/570919/how-can-i-reset-the-laptop-battery-bms |url-status=live |archive-url=https://web.archive.org/web/20250913130751/https://electronics.stackexchange.com/questions/570919/how-can-i-reset-the-laptop-battery-bms |archive-date=2025-09-13 |access-date=2025-09-13 |website=Stack Exchange}}</ref><ref>{{Cite web |date=30 Oct 2023 |title=(i changed every cell in laptop battery then bms locked How to unlock bms of acer e5 laptop battery, total battery in series is 15v but in bms output voltage is 0v i tried to short battery positive to output positive, but still no output, i think bms is locked how to unlock without software help |url=https://old.reddit.com/r/batteries/comments/17jogjr/i_changed_every_cell_in_laptop_battery_then_bms/ |url-status=live |archive-url=https://web.archive.org/web/20250913133735/https://old.reddit.com/r/batteries/comments/17jogjr/i_changed_every_cell_in_laptop_battery_then_bms/ |archive-date=13 Sep 2025 |access-date=13 Sep 2025 |website=[[Reddit]]}}</ref>.

@@ Line 2: / Line 2: @@
 ==How it works==
-When the battery is outside its operating range, such as overcharged, overcharged, overheated, unbalanced(in multi-celled battery packs), the BMS prevents the battery from further usage, limiting damage. However, the BMS should resume normal operation when the battery is back within operating range. Instead, the BMS changes bytes in its memory, leading to a "Permanent Fail (PF)" state, preventing the use of said battery even after reconditioning or repairing.
+When the battery is outside its operating range, such as overcharged, overheated, unbalanced(in multi-celled battery packs), the BMS prevents the battery from further usage, limiting damage. However, the BMS should resume normal operation when the battery is back within operating range. Instead, the BMS changes bytes in its memory, leading to a "Permanent Fail (PF)" state, preventing the use of said battery even after reconditioning or repairing.
 Documentations from known BMS manufacturers such as Texas Instruments said the device can permanently disable the use of the battery pack in case of a "severe failure"<ref>[https://www.ti.com/lit/ug/sluua43a/sluua43a.pdf? https://www.ti.com/lit/ug/sluua43a/sluua43a.pdf?] ([http://web.archive.org/web/20250604023257/https://www.ti.com/lit/ug/sluua43a/sluua43a.pdf Archived])</ref>. However, users report the battery is "bricked" after scenarios like long-term storage, discharging a laptop overnight or using a power tool in a warm environment while charging it cool, indicating the manufacturers have abused the BMS program, exaggerating the nature of the failure as a form of [[self-destructive design]].
@@ Line 24: / Line 24: @@
 ===Consumer electronics===
-[[File:BQ40Z50R3 1.jpg|thumb|A screenshot of a "bricked" battery pack with healthy cells, note the red "PF_EN"]]
+[[File:Texas Instruments BQ40Z50R3 1.jpg|thumb|A screenshot of a "bricked" battery pack with healthy cells, note the red "PF_EN"]]
 The most common consumer electronics using sophisticated battery management system for their multi-cell battery pack are laptop computers. There are many discussions about the battery "lockout" after replacing or recharging individual cells, indicating battery firmware lockout is the main obstacle of battery repair<ref>{{Cite web |date=2022-10-06 |title=How can I reset the laptop battery BMS? |url=https://electronics.stackexchange.com/questions/570919/how-can-i-reset-the-laptop-battery-bms |url-status=live |archive-url=https://web.archive.org/web/20250913130751/https://electronics.stackexchange.com/questions/570919/how-can-i-reset-the-laptop-battery-bms |archive-date=2025-09-13 |access-date=2025-09-13 |website=Stack Exchange}}</ref><ref>{{Cite web |date=30 Oct 2023 |title=(i changed every cell in laptop battery then bms locked How to unlock bms of acer e5 laptop battery, total battery in series is 15v but in bms output voltage is 0v i tried to short battery positive to output positive, but still no output, i think bms is locked how to unlock without software help |url=https://old.reddit.com/r/batteries/comments/17jogjr/i_changed_every_cell_in_laptop_battery_then_bms/ |url-status=live |archive-url=https://web.archive.org/web/20250913133735/https://old.reddit.com/r/batteries/comments/17jogjr/i_changed_every_cell_in_laptop_battery_then_bms/ |archive-date=13 Sep 2025 |access-date=13 Sep 2025 |website=[[Reddit]]}}</ref>.