Huawei E300 Replacement Battery 3.7V 1100mAh Li-ion

Билайн E300 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1100mAh Li-ion battery for the Билайн E300 smartphone. It replaces the original cell when the phone no longer holds charge through a normal day. Capacity is 4.07Wh — matched to the stock specification for this handset.

• E300 fit: The E300 uses a compact 54.05 × 34.10 × 5.40mm cell bay with a low-voltage 3.7V nominal rail. This battery matches those physical and electrical parameters — the connector seats correctly and the charge IC receives the voltage it expects.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench and confirmed the BMS communicates correctly with the phone's charge IC — no false-full trips, no premature cutoff at the low end of the discharge curve.
• First-cycle fuel gauge reset: After fitting this battery, disable fast charging and run one full discharge-to-charge cycle before normal use. The fuel gauge IC on the E300 is calibrated to the old cell's discharge curve — one full cycle lets it recalibrate against the new cell before reporting accurate percentages.

Why the E300 reports wrong battery percentage after a cell swap

The E300 uses a fuel gauge IC that tracks charge state by learning the cell's voltage-versus-capacity curve over time. When you swap in a new cell, that learned curve no longer matches the new cell's actual behaviour. The result is percentage readings that jump, plateau, or drop suddenly — not because the battery is faulty, but because the IC is still referencing old data. One complete discharge down to auto-shutdown followed by a full charge to 100% forces the IC to rebuild its reference map against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem or screen pulls a short burst of high current and the cell voltage drops below the BMS cutoff threshold — even though the gauge still shows charge remaining. On a new cell that hasn't been calibrated, the fuel gauge IC can misjudge how much usable capacity sits below the 3.6V mark. Run the phone down to zero once without interruption, then charge fully to 100%. After that cycle, the cutoff should align closer to the 3.4–3.5V floor the BMS is actually set to.