Qilive RF901 Replacement Battery 3.7V 900mAh Li-ion

Qilive RF901 / TF018E — 3.7V Li-ion Replacement Battery

This is a 3.7V, 900mAh (3.33Wh) lithium-ion battery for the Qilive RF901 and TF018E smartphones. It physically matches the original cell at 53.00 × 34.00 × 4.30mm and connects directly to the stock charge IC and fuel gauge circuit. Replace it when the original no longer holds a useful charge or fails to power the device.

• RF901 and TF018E compatibility: Both models share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail, so one cell covers both. The BMS handshake with each phone's charge IC uses the same protocol — no firmware differences between the two that affect battery recognition.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, monitoring BMS cutoff behaviour at both the low-voltage floor and the charge termination point. The protection circuit tripped correctly at expected thresholds on each run.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging runs into an uncalibrated state register.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still reading percentage values calibrated to the old cell's voltage curve. A new cell has a slightly different voltage-to-capacity slope, so the reported percentage drifts from actual charge state. Under modem or screen load, voltage sags past the hardware cutoff before the gauge reaches 0%. One full discharge-charge cycle — taken all the way down until the phone shuts off, then charged uninterrupted to 100% — resets the coulomb counter against the new curve and eliminates the premature cutoff.

Phone reports wrong battery percentage after cell swap

The fuel gauge IC stores a learned discharge model from the previous cell. After a swap, the stored model no longer matches the new cell's internal impedance or open-circuit voltage profile, so percentage readings appear stuck, jump erratically, or read higher than actual state of charge. The fix is a full calibration cycle: discharge the phone to auto-shutdown, then charge in one uninterrupted session to 100% without using the device. After one complete cycle the gauge recalibrates and percentage reporting stabilises. If jumping persists after two cycles, check that the battery connector is fully seated — a loose pin introduces noise into the voltage sense line.