About this replacement
GSmart S1 / Sierra S1 — 3.7V Li-ion Replacement Battery (BL-182)
This is a 3.7V, 2000mAh Li-ion replacement battery for the GSmart S1 and Sierra S1 smartphones. It carries OEM part number BL-182 and slots into the same battery bay as the factory cell. Dimensions are 74.90 × 62.70 × 4.10 mm — verify these against your existing battery before installing.
- S1 and Sierra S1 compatibility: Both models share the same battery bay geometry, BL-182 part number, and 3.7V power rail to the application processor and modem. One cell fits both variants without modification.
- Bench tested on actual hardware: We ran this cell through charge-discharge cycles on the S1 platform. The BMS accepted the charge profile without triggering overcurrent cutoff, and the protection circuit held the low-voltage cutoff correctly at cell depletion.
- 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 map the new cell's discharge curve before high-current charging pushes energy into an uncalibrated cell — otherwise percentage readings will drift.
Why the GSmart S1 reports wrong battery percentage after a cell swap
The S1 uses a fuel gauge IC that tracks charge state by measuring accumulated current flow — a coulomb counter approach. When you fit a new cell, the IC still holds the charge curve data from the old, degraded battery. The mismatch means the percentage shown can read 40% while the cell is already near voltage floor. One full discharge to auto-shutdown followed by a full uninterrupted charge resets the counter to the new cell's actual capacity.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem or display draws a high current pulse and the cell voltage drops sharply below the BMS cutoff threshold — even though the gauge still shows charge remaining. On a new cell this usually means the fuel gauge IC has not yet calibrated to the fresh discharge curve. Run one complete cycle without interruption. If the shutdowns continue after that cycle, check that the battery contacts are clean and seating flat — a resistive connection causes the same voltage sag under load.