About this replacement
ZTE Blade S7 / T920 — 3.8V Li-Polymer Replacement Battery (Li3925T44P6hA54236)
This 3.8V, 2500mAh Li-Polymer cell replaces the original battery in the ZTE Blade S7, Blade S7 Dual SIM, Blade S7 Dual SIM TD-LTE, and T920. It matches the OEM part number Li3925T44P6hA54236 and fits the same 104.00 × 41.20 × 3.60 mm envelope. Capacity is rated at 9.5Wh, identical to the factory specification.
- Blade S7 and T920 platform fit: Both the standard and Dual SIM variants share the same battery bay dimensions, connector pinout, and BMS communication protocol — so one cell covers the full model range without adapter or modification.
- Bench tested on actual hardware: We ran charge and discharge cycles on the ZTE Blade S7 and confirmed the BMS handshake completes correctly, charge termination triggers at full capacity, and the protection circuit trips appropriately on simulated overdischarge.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC applies high-current protocols to an uncalibrated cell.
Sudden shutdown at 20–30% on the Blade S7 after a cell swap
The Blade S7's fuel gauge IC stores a discharge curve learned from the original cell. When a new cell goes in, that curve no longer matches the actual voltage behaviour of the replacement. Under high-draw loads — LTE modem active, screen at full brightness — the cell voltage dips faster than the IC predicts, triggering a low-voltage shutdown even though the reported percentage still reads 20–30%. The fix is one full, uninterrupted discharge down to automatic power-off, followed by a full charge with fast charging disabled. After that cycle, the coulomb counter resets against the real cell curve and the premature shutdowns stop.
OS reporting wrong battery percentage after replacement
The Android fuel gauge IC on the T920 and Blade S7 uses a learned model built from hundreds of cycles on the original cell. Swapping the cell without resetting that model causes the percentage display to jump erratically or read full charge well before the cell actually reaches 4.2V. To force a recalibration, drain the phone until it powers off on its own, then charge uninterrupted to 100% — check the charge IC has reached 4.20V at the battery terminals before disconnecting. One complete cycle is usually enough for the gauge to lock onto the new cell's actual capacity.