TP-Link Neffos C7 NBL-35B3000 Compatible Battery 3.85V 2900mAh

TP-Link Neffos C7 Dual SIM — 3.85V Li-Polymer Replacement Battery (NBL-35B3000)

This is a 3.85V, 2900mAh (11.17Wh) Li-Polymer replacement battery for the TP-Link Neffos C7 Dual SIM smartphone. It fits the Neffos C7 Dual SIM, Neffos C7 Dual SIM LTE AM, TP910C, and TP910A. It replaces OEM part number NBL-35B3000 directly.

• Neffos C7 / TP910 platform fit: The TP910C and TP910A share the same battery bay dimensions, connector orientation, and BMS handshake protocol as the standard C7 Dual SIM variants. One cell covers all four models — no adapter or wiring change needed.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the TP910 platform. The BMS accepted charge handshake on first connect, held voltage under simultaneous LTE and display load, and tripped protection correctly at the low-voltage cutoff threshold.
• Fuel gauge recalibration after installation: On first use after fitting this cell, disable fast charging and complete one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC starts pushing higher current into an uncalibrated cell.

Sudden shutdown at 20–30% on the Neffos C7 after a cell swap

The Neffos C7 uses a coulomb-counter fuel gauge IC that was calibrated against the original cell's discharge curve. A new cell with a slightly different internal resistance profile hits a voltage cliff under combined modem and display load that the fuel gauge does not anticipate. The phone cuts power before the reported percentage reaches zero. One full discharge-charge cycle at standard current retrains the counter against the new cell's actual voltage-versus-capacity curve. After that cycle, shutdowns at 20–30% stop.

Phone shows incorrect or jumping battery percentage after replacement

When the original battery degrades significantly before replacement, the fuel gauge IC anchors its full-charge and empty reference points to that degraded cell. Fitting a fresh 2900mAh cell gives the gauge a mismatch it cannot resolve until it sees a complete discharge-to-zero followed by a full charge to 100%. Until that cycle completes, the reported percentage jumps erratically or reads high while the phone still shuts down early. Drain the phone to automatic power-off, then charge uninterrupted to 100% at the standard 5V charge rate to reset the reference points.