Bose QuietComfort Earbuds Charging Case Compatible Battery 3.7V 800mAh

Bose QuietComfort Earbuds Charging Case — 3.7V Li-Polymer Replacement Battery (762936HV-1)

This is a 3.7V, 800mAh Li-Polymer battery for the Bose QuietComfort Earbuds Charging Case. It replaces OEM part 762936HV-1 — the internal cell that keeps the case topped up so it can recharge the earbuds away from AC power. When this cell degrades, the case loses the ability to deliver multiple full charges to the earbuds between plug-ins.

• QuietComfort Earbuds Charging Case fit: The case runs a single Li-Polymer cell at 3.7V nominal to drive its internal charging circuit. This replacement matches the OEM voltage rail and physical footprint (38.30 × 30.00 × 7.80mm), so the BMS handshake completes without error codes on the case LED indicators.
• Bench tested on actual hardware: We cycled this cell through charge-discharge on the case's charging board. The BMS accepted the new cell on first connection, the charge LED sequenced normally, and the cell held voltage at 4.17V at full charge — within 1% of OEM spec.
• First-cycle tip for the QuietComfort case: After fitting the new cell, run the case to flat on the earbuds before plugging into USB-C. The case firmware recalibrates its fuel gauge on that first full discharge — skipping it causes the LED indicator to misreport remaining charge for weeks.

Why the QuietComfort case shows full charge but cuts the earbuds off early

The case relies on its internal fuel gauge IC to track how much charge the 800mAh cell holds. A degraded original cell loses capacity unevenly — the gauge still reads 100% at rest voltage but the cell voltage collapses the moment the charging circuit draws current into the earbuds. The result is a case that looks fully charged but can only deliver one partial charge cycle instead of two or more. Replacing the cell resets this mismatch, but the gauge needs one full discharge cycle to re-anchor its low-voltage reference point accurately.

Case LED stuck on red after battery replacement

A solid or blinking red LED after fitting a new cell usually means the case BMS has not completed its handshake with the replacement pack. This happens when the new cell ships at storage voltage — typically around 3.6–3.65V — which sits below the threshold the case expects to see before it allows normal charge sequencing. Plug the case into USB-C for at least 15 minutes without placing the earbuds inside. That lets the case charge the new cell directly to 3.8V, at which point the BMS re-initialises and the LED returns to amber or white charging status.