MTC 252 Compatible Battery 3.7V 700mAh Li-ion Smartphone

MTC 252 / 262 / 352 / Qwerty 650 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 700mAh Li-ion cell replacement for the MTC 252 and its sibling handsets — the 262, 352, and Qwerty 650. All four models share the same battery bay dimensions and connector, making one cell SKU compatible across the range. Capacity is 700mAh (2.59Wh), matching the original specification.

• Cross-model fit — 252, 262, 352, Qwerty 650: These handsets share a common PCB platform with the same 3.7V voltage rail, identical physical footprint (46.60 × 33.90 × 4.70mm), and the same connector pinout. The BMS handshake is consistent across the range, so one cell services all four models without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the MTC platform. The BMS accepted charge from a standard 5V USB input without fault flags, and the protection circuit tripped correctly at the low-voltage cutoff threshold — no overcharge or undervoltage events logged.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle before resuming normal use. This gives the fuel gauge IC time to map the new cell's discharge curve — without it, the OS reads inaccurate percentages and can trigger early shutdown protection based on stale calibration data.

Why the MTC 252 shuts down suddenly at 20–30% after a cell swap

The fuel gauge IC on the MTC 252 stores a discharge curve calibrated to the original cell. When a new cell goes in, the IC still uses that old curve to estimate remaining capacity. At around 20–30%, the new cell's actual voltage drops below what the modem and display need to sustain load — but the gauge hasn't predicted the cliff because it's reading from the wrong map. The phone cuts power before the gauge reaches zero. One full discharge-to-charge cycle resets the coulomb counter and lets the IC rebuild an accurate curve against the new cell.

Phone not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage. If this battery has been sitting unused for several months, its resting voltage may have dropped below 2.5V per cell — the threshold at which the BMS enters lockout to prevent damage. The phone won't respond to a normal charge attempt because the BMS blocks current input at this voltage. Connect the phone to a charger and leave it undisturbed for 15–30 minutes; most charge ICs send a low-current trickle that gradually lifts the cell above the 2.5V recovery threshold, at which point the BMS unlocks and normal charging resumes.