Mobistel EL350 Replacement Battery BTY26169 3.7V 1200mAh

Mobistel EL350 / EL350 Dual — 3.7V Li-ion Replacement Battery (BTY26169)

This is a 3.7V, 1200mAh Li-ion cell built to fit the Mobistel EL350 and EL350 Dual smartphones. It replaces OEM part BTY26169 and drops into the same battery bay using the original connector. Dimensions are 54.60 × 34.00 × 5.50mm — check these against your existing cell before ordering.

• EL350 and EL350 Dual compatibility: Both variants share the same battery bay geometry, connector pinout, and 3.7V nominal voltage rail. One cell fits both. The BMS handshake is identical across the two models, so no firmware difference affects charging behavior.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the EL350 platform. The BMS accepted the new cell without rejection flags, and protection cutoffs triggered correctly at low-voltage thresholds during deep discharge testing.
• Fuel gauge recalibration on first use: After fitting this cell, disable any fast-charge mode and run one complete discharge-to-charge cycle at standard current. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the EL350 after a cell swap

This happens because the fuel gauge IC still holds the discharge curve from the old, degraded cell. When the new cell hits a voltage point the IC hasn't mapped yet, the phone reads it as critically low and shuts down — even though charge remains. The fix is one full uninterrupted discharge down to auto-off, followed by a full charge without interruption. After that cycle, the coulomb counter recalibrates and reported percentage aligns with actual cell state.

EL350 not powering on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the cell voltage drops below approximately 2.5V, the BMS enters lockout mode and blocks current flow to protect the cell from damage. The phone will show no response — no boot logo, no charging indicator. Connect the phone to a wall adapter and leave it for 15–20 minutes without pressing the power button. The charge IC needs time to push a trickle current past the BMS lockout threshold before normal charging resumes. Once the LED or screen shows a charging indicator, the BMS has re-initialised.