About this replacement
Switel M910 — 3.7V Li-ion Replacement Battery (M910)
This is a 3.7V Li-ion cell rated at 1000mAh (3.7Wh), built to replace the original battery in the Switel M910 candybar-style mobile phone. It fits the M910 directly, restoring power to calls, messaging, and basic applications when the original cell has degraded or failed. Dimensions are 60.17 × 38.05 × 4.55mm — verify against your existing cell before fitting.
- M910 platform fit: The M910 runs a single-cell 3.7V Li-ion supply rail with a fixed connector and BMS handshake matched to this form factor. Swapping to any cell outside this voltage and footprint breaks the charge circuit handshake and can trigger a BMS lockout.
- Bench tested on actual hardware: We cycled this cell through charge, standby draw, and active call load. The BMS held regulation across the full discharge curve, with cutoff triggering correctly at the low-voltage threshold — no premature trips under modem load.
- Fuel gauge recalibration on first use: On first use after installation, disable any fast-charge mode and run one full discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell, preventing erratic percentage readings from the first charge onward.
Sudden shutdown at 20–30% on the Switel M910
This is a voltage cliff failure, not a capacity issue. At 20–30% state-of-charge, the cell voltage drops sharply under combined modem and screen load, hitting the BMS cutoff threshold before the fuel gauge reads zero. It happens most often on cells that have been in storage — the cell's internal resistance rises during storage, amplifying the voltage sag under load. Run one full discharge cycle after fitting the new cell to let the fuel gauge IC re-anchor its low-end voltage reference.
M910 reporting wrong battery percentage after cell replacement
The fuel gauge IC on the M910 stores a charge curve calibrated to the original cell's impedance profile. When a new cell goes in, that stored curve no longer matches the actual discharge behaviour, so the reported percentage drifts — often reading full charge earlier than the cell actually is, or dropping suddenly near the bottom. A single uninterrupted discharge from 100% down to automatic shutdown, followed by a full charge, forces the coulomb counter to reset against the new cell. After that cycle, percentage reporting stabilises. Do not interrupt the first discharge cycle by topping up mid-way.