TCL 10 SE Replacement Battery 3.85V 3850mAh Li-Polymer

TCL 10 SE / T766S — 3.85V Li-Polymer Replacement Battery

This 3850mAh Li-Polymer cell replaces the original battery in the TCL 10 SE (model T766S). It runs at 3.85V nominal and delivers 14.82Wh total capacity. If your 10 SE shuts down unexpectedly, drains fast, or won't hold a charge, this is the direct cell swap.

• TCL 10 SE / T766S compatibility: Both model identifiers share the same battery bay dimensions (83.10 × 62.68 × 4.30mm), the same 3.85V charging profile, and the same BMS connector pinout — one cell covers both variants without modification.
• Bench tested on actual hardware: We cycled this cell through the TCL 10 SE charge IC and confirmed the BMS handshake completes correctly, charge current ramps as expected, and the protection circuit trips at the correct over-discharge threshold.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one full discharge-to-charge cycle before returning to normal use. The 10 SE fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve — skipping this step produces erratic percentage readings for the first several days.

Sudden shutdown at 20–30% on the TCL 10 SE after a cell swap

The TCL 10 SE's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, the stored curve no longer matches actual cell voltage under load — the modem and display together can pull enough current to cause a voltage cliff the gauge doesn't anticipate. The phone reads 25% but the new cell's open-circuit voltage is already near the BMS cutoff threshold under that load spike. One complete discharge-charge cycle forces the coulomb counter to re-anchor to the new cell's real capacity endpoints and eliminates most premature shutdowns.

USB-PD fast charge not triggering on the first cycle after replacement

On the first charge cycle with a new Li-Polymer cell, the charge IC may default to a lower trickle current while it verifies the BMS negotiation is stable — this can look like fast charge has stopped working. The USB-PD handshake between the charger and the phone's charge IC requires the BMS to confirm cell state before allowing high-current delivery. Plug in the original TCL charger rather than a third-party adapter for the first cycle, since proprietary charge protocols are more tolerant of an uncalibrated cell state. After one full cycle completes, fast charge resumes at the standard rate.