Sony Ericsson T60 BST-17 Replacement Battery 3.7V 900mAh

Sony Ericsson T60 / T62u Series — 3.7V Li-Polymer Replacement Battery (BST-17)

This is a 3.7V, 900mAh Li-Polymer replacement cell for the Sony Ericsson T60, T60c, T61c, and T62u candybar mobile phones. It uses OEM part number BST-17 and matches the original cell's physical dimensions at 51.44 × 34.20 × 5.40mm. Swap it in when the original cell no longer holds a charge or fails to power the phone through a normal day of use.

• T60 / T61c / T62u platform fit: These four models share the same BST-17 battery bay, connector pinout, and charge circuit. The BMS handshake on each is identical, so one cell covers the full variant range without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the T62u. The BMS held the charge cutoff at 4.2V and the low-voltage cutoff triggered cleanly at 3.0V, with no thermal events during fast charge.
• First-cycle fuel gauge reset on the T60: After installing this cell, run one complete discharge down to the phone's auto-shutoff, then charge uninterrupted to 100% before using the phone normally. The T60's fuel gauge IC was calibrated to the original cell's discharge curve — one full cycle corrects it against the new cell so percentage readings stay accurate.

Why the T60 reports wrong battery percentage after a cell swap

The T60 uses a coulomb-counting fuel gauge IC that builds its percentage model from accumulated charge and discharge data on the original cell. When you install a new cell, that learned curve no longer matches the new cell's actual voltage-versus-capacity profile. The gauge keeps reading against stale reference data, which is why it might show 80% when the phone is close to shutoff. One full discharge-to-shutoff followed by an uninterrupted charge to 4.2V resets the reference and restores accurate reporting.

Sudden shutdown at 20–30% on the BST-17 replacement cell

This happens when the fuel gauge IC hasn't recalibrated yet and the phone hits the cell's real voltage cliff before the OS thinks it should. Under call or backlight load, cell voltage drops sharply below 3.2V — the BMS trips the cutoff and the phone shuts down with percentage still showing on screen. It's not a faulty cell; it's a calibration lag. Run the full discharge-recharge cycle described above, and the shutoffs will align with actual remaining capacity.