BlackBerry C-X2 Replacement Battery 3.7V 1900mAh Li-ion

BlackBerry 8800 Series — 3.7V Li-ion Replacement Battery (C-X2 / BAT-11005-001)

This is a 3.7V, 1900mAh Li-ion replacement battery for the BlackBerry 8800, 8800c, 8800r, and 8820. It uses OEM part numbers C-X2, BAT-11005-001, and ASY-14321-001. Swap it in when the original cell no longer holds a useful charge through a working day.

• 8800 series compatibility: The 8800, 8800c, 8800r, and 8820 all share the same battery bay dimensions, connector pinout, and 3.7V charging rail. One cell fits the entire group — no hardware modification needed.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the 8800 platform. The BMS accepted the charge IC handshake without fault codes, and voltage held steady above 3.5V under combined radio and display load.
• Fuel gauge recalibration on first use: After installing this cell, disable any fast-charge accessory and run one full discharge-to-charge cycle before normal use. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Why the BlackBerry 8800 reports wrong battery percentage after a cell swap

The 8800 uses a fuel gauge IC that builds its percentage estimate from a stored discharge curve tied to the old cell. When you fit a new cell, that stored curve no longer matches actual cell behaviour. The IC will overestimate or underestimate remaining charge until it collects real data. One full discharge from 100% down to automatic shutdown, followed by a complete charge to 100%, forces the IC to rewrite its reference curve against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the BMS cutoff threshold under combined modem and screen load — even though the percentage display still reads 20–30%. The fuel gauge IC has not yet calibrated its low-voltage cliff for the new cell, so it does not flag the impending cutoff in time. The BMS trips at approximately 3.0V per cell to protect the chemistry, and the phone shuts down instantly. Complete that first full discharge-charge cycle and the gauge IC will start predicting the voltage cliff accurately.