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Bose QuietComfort 45

The Bose QuietComfort 45 is a noise cancelling headphone model that was released on September 23, 2021. Its model number is 845217-0100.

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Peter Carroll @petercarro55117

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Posted: yesterdaySep 30, 2026

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I have QC45s. One morning, I put them on, and nothing happened. If I plug in the USB to charge, the light gives one flash, and the laptop does a ba-beep as if something is connected. But no other signs of life no matter what.

I called Bose, went through diagnosis, and they said it is dead and offered me a tiny discount on new ones.

I disassembled them a bit and read almost 4V on the battery. So, it's not that.

Has anyone else experienced this? Do wires break in the headband? Is there any other possible cause? These things aren't meant to be serviced. But for $500, I will try...

Answer this question I have this problem too

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If you were to leave the headset/battery unused for a couple days after having it charged full, does it stay at a high voltage, or does the voltage decay quickly even if not under use?

Checking the battery voltage is a great step! The only caveat is that that testing is not under load and can therefore give a false sense of security.

Cheers

7 hours agoOct 1, 2026 by MeekVixen

If this noise cancelling headphone is used regularly, not dropped or drowned from rain or falling into a pool or river stream, mishandled several years can be expected for real world lifetime use before battery capacity is reduced or dies. Most rechargeable headphones, earbuds and hearing aids are not made for battery replacement. Diyers can attempt battery replacement after a warranty period elapsed. Battery packs usually have labeling for type (nicad, nmh or lithium ion), pack voltage and capacity (milliamps/mah). Without knowing what voltage is printed on the battery pack, either its dead and cannot recharge or electronics failed. You can try a temporary battery pack made up from AAA or AA batteries, disconnect suspect battery and wire in the temporary pack and see if your headphone powers up. Voltage from AA/AAA non rechargeable batteries can be wired up and closely match original battery voltage, + or - up to one volt,

6 hours agoOct 1, 2026 by F Dryer

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If you were to leave the headset/battery unused for a couple days after having it charged full, does it stay at a high voltage, or does the voltage decay quickly even if not under use?

Checking the battery voltage is a great step! The only caveat is that that testing is not under load and can therefore give a false sense of security.

Cheers — MeekVixen
If this noise cancelling headphone is used regularly, not dropped or drowned from rain or falling into a pool or river stream, mishandled several years can be expected for real world lifetime use before battery capacity is reduced or dies. Most rechargeable headphones, earbuds and hearing aids are not made for battery replacement. Diyers can attempt battery replacement after a warranty period elapsed. Battery packs usually have labeling for type (nicad, nmh or lithium ion), pack voltage and capacity (milliamps/mah). Without knowing what voltage is printed on the battery pack, either its dead and cannot recharge or electronics failed. You can try a temporary battery pack made up from AAA or AA batteries, disconnect suspect battery and wire in the temporary pack and see if your headphone powers up. Voltage from AA/AAA non rechargeable batteries can be wired up and closely match original battery voltage, + or - up to one volt, — F Dryer

Malcolm Parker @malcolmpar95155 Rep: 419 3 · Answer 1 · 2026-10-01T09:34:46-07:00

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Malcolm Parker @malcolmpar95155

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Posted: 9 hours agoOct 1, 2026

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Since the battery is around 4 V, I’d check the power/charging board and the headband flex cables next. A broken flex or connector can give you that brief USB connection without actually powering the headphones.

Also inspect the board for corrosion or a failed component before assuming the battery is good just because it has voltage.

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oldturkey03 @oldturkey03 Rep: 861.3k 1.5k 978 2.4k · Answer 2 · 2026-10-01T18:57:45-07:00

@petercarro55117 the laptop chiming means the main logic board is actually alive and communicating when fed 5V via USB. it is possible that this issue is a physical break in the power line between the battery and the logic board, or even a failure of the power switch.

In the QC45, the battery sits in the left earcup, while the logic board is in the right earcup. Power has to travel from the battery to the logic board through the thin wires inside the headband. If those wires have fractured from the stress of folding the hinges, power will not reach the board. Use a multimeter in continuity mode to trace the battery's positive and negative connections from the left earcup solder pads over to the power input terminals on the right logic board. If there is no continuity, you have a broken headband wire that needs to be bypassed or re-run.

If the voltage from the battery is successfully reaching the right logic board, the power switch becomes your primary suspect. Use a multimeter to test for continuity across the switch's pins while toggling it to the "On" position. If the switch measures open while in the on position, it has failed and requires replacement. Finally, be sure to inspect the board for bad solder joints or other visibly damaged components.

Bose QuietComfort 45

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