Doogee F1 Replacement Battery H0521F10445 3.8V 1800mAh

Doogee F1 — 3.8V Li-ion Replacement Battery (H0521F10445)

This is a 3.8V, 1800mAh Li-ion replacement battery for the Doogee F1 smartphone. It matches the original OEM part number H0521F10445 and fits directly into the F1 chassis. Use this when the original cell has degraded, stopped holding a charge, or swells and needs to be replaced.

• Doogee F1 fitment: The F1 uses a single-cell 3.8V Li-ion pack with a fixed connector and BMS handshake tied to the phone's charge IC. This replacement matches that connector pinout and voltage profile, so the charge IC recognises the cell and allows normal charging to proceed.
• Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on the bench. The BMS reported correct voltage at each stage, and the charge IC accepted the cell without triggering a fault or rejection handshake.
• 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 current into an uncalibrated cell.

Why the Doogee F1 reports wrong battery percentage after a cell swap

The F1's fuel gauge IC builds a discharge curve model based on the old cell. When a new cell goes in, that model no longer matches the actual cell behaviour. The result is percentage readings that jump or stall — often freezing at one value then dropping suddenly. One full discharge-charge cycle lets the coulomb counter reset and map the new cell's actual capacity curve. After that cycle, percentage accuracy returns to normal.

Sudden shutdown at 20–30% on the Doogee F1

This happens when the cell voltage drops below the phone's minimum threshold under load — even though the OS still shows charge remaining. The modem, screen backlight, or a background process pulls current the cell cannot sustain at that state of charge. The phone shuts down to protect the cell rather than risk a hard undervoltage. After replacement, run one full discharge to around 3.2V under normal use before recharging — this aligns the fuel gauge cutoff point with the new cell's actual low-voltage floor.