About this replacement
Lenovo A300 / A590 / A750 — 3.7V Li-ion Replacement Battery (BL192)
The BL192 is a 3.7V, 2050mAh Li-ion cell that fits the Lenovo A300, A590, and A750 smartphones. It slots into the original battery bay and connects via the standard three-contact strip on the rear housing. Capacity is 2050mAh (7.59Wh) — matching the factory spec.
- A300, A590, and A750 compatibility: All three models share the same physical footprint, contact layout, and BMS handshake protocol. The BL192 cell works across this range without any connector adapter or firmware change.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on an A300 unit. The BMS accepted the cell without error flags, charge termination triggered correctly at 4.2V, and protection cutoff activated at the expected low-voltage threshold.
- First-cycle fuel gauge reset: After installing this cell, run one complete discharge to auto-shutoff, then charge to 100% without interruption. This lets the fuel gauge IC map the new cell's discharge curve and eliminate early percentage errors.
Why the A300 reports wrong battery percentage after a cell swap
The A300 uses a fuel gauge IC that tracks charge by counting coulombs against a stored discharge curve from the original cell. When you fit a new cell, that stored curve no longer matches the actual cell chemistry, so percentage readings drift — often reading high and then dropping sharply. One full uninterrupted discharge-to-charge cycle forces the IC to recalibrate against the new cell's real voltage profile. After that cycle, readings stabilise and the gauge tracks accurately again.
Sudden shutdown at 20–30% on the BL192 after installation
This happens when the fuel gauge IC is still calibrated to the old, degraded cell curve. The phone thinks 25% charge remains, but the new cell's actual open-circuit voltage at that reported state of charge sits below what the modem or display draw requires under load. The phone hits the hardware undervoltage floor and cuts out even though the gauge hasn't reached zero. Run one full discharge cycle — letting the phone shut itself off naturally — then charge to 100%. After that, the cutoff threshold aligns with real charge state, and the phone should hold voltage down to approximately 3.4–3.5V before shutdown.