TP-Link Neffos N1 Compatible Battery 3.85V 3000mAh

TP-Link Neffos N1 / TP908A — 3.85V Li-Polymer Replacement Battery

This 3.85V, 3000mAh (11.55Wh) lithium-polymer cell replaces the original battery in the TP-Link Neffos N1 and TP908A smartphones. It matches the factory cell dimensions at 84.14 × 63.80 × 3.62mm, fitting the existing battery bay without modification. Capacity is sourced from the product specification — not estimated.

• Neffos N1 and TP908A compatibility: Both the Neffos N1 and TP908A share the same battery bay geometry, connector pinout, and 3.85V nominal voltage rail. The BMS handshake is identical across both variants, so one cell covers the full model range.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Neffos N1 platform. The BMS accepted charge current without error flags, and the protection circuit tripped correctly at the low-voltage cutoff threshold — no runaway, no false shutdowns at full charge.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge down to automatic power-off, then charge to 100% uninterrupted. The Neffos N1 fuel gauge IC maps its coulomb counter against the new cell's discharge curve during that first cycle — skipping it causes percentage reporting errors for weeks.

Sudden shutdown at 20–30% on the Neffos N1 after cell replacement

This is a voltage-cliff problem, not a capacity problem. The fuel gauge IC still holds the discharge curve from the degraded original cell, so it reports 25% remaining at a point where the new cell's actual voltage is already dropping steeply under modem and display load. When voltage sags below approximately 3.4V under that combined load, the BMS cuts power to protect the cell — even though the percentage indicator says charge remains. One full uncalibrated discharge cycle resets the coulomb counter and eliminates the early cutoff.

USB fast charge not activating after fitting the replacement cell

The Neffos N1 charge IC negotiates fast charge protocol on each boot and on each charge session start. A new high-impedance cell can cause the charge IC to fall back to standard 5V input on the first one or two sessions because the impedance reading sits outside the expected window for a conditioned cell. This is not a fault with the replacement cell or the charger. Run two standard charge cycles first — cell impedance drops as the lithium intercalation layers settle — then reconnect your original fast charger and the protocol handshake should complete normally.