Microsoft Lumia 929 Compatible Battery BV-5QW 3.8V 2200mAh

Microsoft Lumia 929 / 930 — 3.8V Li-ion Replacement Battery (BV-5QW)

This is a 3.8V, 2200mAh Li-ion replacement battery carrying OEM part number BV-5QW. It fits the Microsoft Lumia 929 (RM927) and Lumia 930 Windows Phone handsets. Swap it in when the original cell no longer holds charge through a normal day of use.

• Lumia 929 / RM927 / Lumia 930 fitment: All three share the same chassis dimensions, battery bay, and connector pinout. The BV-5QW spec — 3.8V nominal, 66.96 × 51.28 × 5.46mm — maps directly to that bay without modification.
• Bench tested on actual hardware: We cycled this cell through charge and full discharge on the bench. The BMS held within the expected 3.0V lower cutoff and 4.35V upper limit, with no erratic cutoff events during the discharge phase.
• First-cycle fuel gauge recalibration: After fitting this cell, disable fast charging and run one complete discharge-charge cycle at standard current. The Lumia's fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve on that first pass — skip it and percentage readings will drift for days.

Sudden shutdown at 20–30% on the Lumia 929 after a cell swap

A new cell has a discharge curve the fuel gauge IC has never seen. When the phone pulls high current — LTE modem, screen at full brightness, camera — the terminal voltage can sag below the BMS cutoff threshold even though the reported state-of-charge says 25%. The BMS shuts the output rail immediately to protect the cell. This is not a defective battery; it is the IC working from a stale lookup table. Run one full discharge to the automatic shutdown point, then charge uninterrupted to 100%, and the IC remaps its voltage-to-percentage curve against the new cell.

Phone will not power on after the BV-5QW sat in storage

Li-ion cells in storage self-discharge slowly. If the cell voltage drops below approximately 2.5V per cell, the BMS enters lockout mode and blocks all output to prevent further damage. The phone sees no voltage on the battery rail and will not respond to the power button. Connect the phone to a wall charger — not a USB port — and leave it untouched for 20 to 40 minutes. The charge IC trickle-charges the cell above the BMS reactivation threshold, typically around 2.9V, at which point the BMS reopens the output and the phone will boot normally.