Hagenuk E50 F100 Replacement Battery 3.7V 900mAh

Hagenuk E50 — 3.7V Li-ion Replacement Battery (F100)

This is a 3.7V, 900mAh lithium-ion replacement battery for the Hagenuk E50 mobile phone. It fits the OEM part number F100 slot directly. Use it when the original cell no longer holds a charge or the phone shuts down unexpectedly during calls or messaging.

• E50 fit and connector match: The E50 uses a compact form factor at 53.00 × 34.00 × 4.30mm with a fixed connector pinout. This cell matches that physical envelope and pin layout so the BMS handshake completes correctly on boot.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge passes on the E50 platform. The BMS accepted the cell without fault codes, and the protection circuit responded correctly to overcharge and over-discharge thresholds.
• Fuel gauge recalibration on first install: On first use after fitting, run one full discharge down to automatic cutoff, then charge uninterrupted to 100%. This gives the E50's fuel gauge IC a clean reference curve against the new cell so percentage readings stay accurate from the first cycle onward.

Why the E50 reports wrong battery percentage after a cell swap

The E50 uses a fuel gauge IC that builds its percentage model from the discharge curve of the original cell. When you fit a new cell, the IC is still running calculations against the old curve. This causes the reported percentage to lag or jump, especially between 40% and 80%. One full uninterrupted discharge-charge cycle resets the coulomb counter reference. After that cycle, percentage tracking aligns to the new cell's actual capacity.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under modem or screen load — a voltage cliff rather than a gradual drain. The E50's protection circuit cuts power when cell voltage sags below roughly 3.0V under load, even if the fuel gauge still shows remaining charge. An uncalibrated fuel gauge makes this worse because the shutdown looks earlier than the true state of charge. Run the recalibration cycle first; if shutdowns continue, check that the battery connector is fully seated, as a loose contact increases resistance and deepens the voltage sag under load.