About this replacement
LG Q7 Plus / Q725L — 3.85V Li-Polymer Replacement Battery (BL-T28)
This 3.85V, 2600mAh (10.01Wh) Li-Polymer cell replaces the OEM BL-T28 battery in the LG Q725L, Q7+, and Q7 Plus. It fits the full Q7 Plus TD-LTE family and over 20 additional Q7 variants sharing the same battery bay and connector. Swap it when the original cell no longer holds a usable charge through a normal day.
- Q7 Plus platform compatibility: Every model in this cluster runs the same 3.85V power rail, uses the same ZIF-style flex connector, and communicates with the same fuel gauge IC. That shared architecture is why one cell covers the full Q7+ lineup without modification.
- Bench tested on actual hardware: We cycled this cell on a Q7 Plus unit, confirmed BMS handshake on power-up, and verified the charge IC accepted a full CC/CV charge cycle without thermal flags or cutoff events.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes into an uncalibrated state.
Why the Q7 Plus reports wrong battery percentage after a cell swap
The Q7 Plus uses a coulomb-counter fuel gauge IC that builds its reference model from the original cell's discharge curve over many cycles. When you install a new cell, that learned model no longer matches the actual cell behaviour. The gauge reads voltage and estimates remaining capacity from stale data, so percentages appear inflated or stuck. One full discharge down to auto-shutdown followed by a complete uninterrupted charge cycle forces the IC to write a new reference curve.
Sudden shutdown at 20–30% charge remaining
This is a voltage cliff failure, not a capacity problem. Under peak load — modem handoff, screen at full brightness, GPS active — the cell voltage drops sharply below the BMS cutoff threshold even though the gauge still shows 20–30%. An aged or deeply discharged cell has higher internal impedance, so voltage sags faster under load than at rest. Run the phone through two full calibration cycles and check that resting voltage after a full charge sits at or above 4.35V before drawing heavy load.