BF6X Motorola XT882 Replacement Battery 3.7V 1800mAh

Motorola XT882 / Droid 3 — 3.7V Li-ion Replacement Battery (BF6X / SNN5885A)

This is a 3.7V, 1800mAh Li-ion replacement battery for the Motorola XT882, Droid 3, XT862, and Milestone 3, among others. It uses OEM part numbers BF6X, SNN5885, and SNN5885A. The cell fits the original battery bay and connects to the same BMS contacts.

• XT882 / Droid 3 platform fit: These models share the same 3.7V single-cell architecture, identical connector pitch, and the same BMS handshake protocol — which is why one cell covers all of them. Voltage regulation and charge termination logic are consistent across this lineup.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the XT882. The BMS accepted charge termination cleanly at 4.2V, and cutoff under load held within spec. No false-full triggers or mid-discharge drops outside expected voltage curve.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — preventing erratic percentage readings from the first day.

Sudden shutdown at 20–30% on the XT882 after a cell swap

This is a voltage cliff problem, not a capacity problem. The fuel gauge IC was calibrated to the old cell's discharge curve. When modem activity or screen load spikes current draw, the new cell's terminal voltage drops faster than the IC predicts — the phone interprets this as a critical voltage event and cuts power. The fix is one full discharge to near-zero followed by a full uninterrupted charge. After that cycle, the coulomb counter re-anchors to the actual cell behaviour and shutdown events stop.

Device won't power on after the BF6X sat in storage

Li-ion cells in storage self-discharge over time. If the cell drops below approximately 2.5V, the BMS enters lockout mode and blocks charge current to prevent venting a deeply discharged cell. The phone shows nothing — no charging screen, no vibration. Connect to a wall charger (not USB from a PC) and leave it for 15–20 minutes without attempting to power on. Most BMS circuits on this platform accept a trickle-current recovery sequence from a 5V wall adapter and will exit lockout once the cell climbs back above 3.0V.