BlackBerry Bold Touch 9900 JM1 Replacement Battery 3.7V 1250mAh

BlackBerry Bold Touch 9900 — 3.7V Li-ion Replacement Battery (JM1)

This is a 3.7V, 1250mAh Li-ion cell that fits the BlackBerry Bold Touch 9900 and 9930. It replaces OEM part numbers JM1, BAT-30615-006, and J-M1. If your original cell has degraded, won't hold charge, or has swollen, this is the direct swap.

• Bold Touch 9900, 9930, Pluto, Montana compatibility: These models share the same battery bay geometry, 3.7V nominal voltage rail, and JM1 connector footprint. The BMS handshake uses the same authentication protocol across the series, so one cell covers all listed variants without modification.
• Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on a Bold Touch 9900. The BMS accepted the charge without error flags, voltage held steady under screen-on and modem load, and the protection circuit triggered correctly at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: After installing this cell, run one complete discharge to near-empty before charging to 100%. The Bold Touch 9900's fuel gauge IC holds the old cell's discharge curve in memory. Without one full cycle, the OS percentage counter will be reading against stale calibration data — not the actual charge state of the new cell.

Why the Bold Touch 9900 shuts down suddenly at 20–30% after a cell swap

The 9900's fuel gauge IC uses a coulomb counter calibrated to the original cell's internal resistance profile. A new cell has different impedance characteristics, so the counter miscalculates remaining charge. Under modem-load or screen brightness spikes, the actual cell voltage drops below the protection circuit's cutoff threshold before the OS percentage reflects it. The phone interprets this as a sudden shutdown rather than a low-battery event. One full discharge-to-charge cycle resets the calibration and eliminates the cliff.

Phone warm near the battery slot on the first charge after replacement

A new cell arrives with a higher internal impedance than a cell that has been cycled. On the first charge, the charge IC pushes current into a cell that resists it slightly more than usual, generating extra heat at the junction. This is normal and typically resolves after two to three charge cycles as impedance drops. If the phone remains warm beyond the third full charge, check that the replacement cell is seated flat with no gap at the contact pads — a misaligned cell forces the charge IC to work harder to maintain contact voltage.