About this replacement
Emporia Telme C155 — 3.7V Li-ion Replacement Battery (AK-C155)
This is a 3.7V, 1200mAh lithium-ion battery that replaces the original AK-C155 cell in the Emporia Telme C155 mobile phone. It fits both the Telme C155 and C155 variants. Capacity figures are taken from our product data — 4.44Wh total energy.
- Telme C155 platform fit: Both C155 variants share the same battery bay dimensions, connector pinout, and BMS handshake. One cell specification covers both. The 49.35 × 48.30 × 5.50mm footprint matches the original housing with no modification needed.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a C155 unit. The BMS accepted the cell without error flags, charge termination triggered at full voltage, and the protection circuit responded correctly to simulated over-discharge conditions.
- Fuel gauge recalibration on first use: After fitting this battery, run one complete discharge-charge cycle with fast charging disabled if your C155 supports it. The fuel gauge IC reads a stored discharge curve from the old cell — giving it one uninterrupted cycle lets it recalibrate against the new cell before reporting accurate percentages.
Why the Telme C155 shuts down suddenly at 20–30% remaining
This is a voltage cliff problem. An aged or high-impedance cell cannot maintain the voltage rail under the brief current spikes the baseband processor draws during a call or screen wake. The phone's power management IC sees the voltage drop below its cutoff threshold and triggers a hard shutdown — even though the fuel gauge still shows charge remaining. A fresh cell with lower internal resistance sustains the voltage under that load spike. After fitting the replacement, run a full discharge to confirm the gauge recalibrates before drawing conclusions about shutdown behaviour.
Phone reporting wrong battery percentage after cell swap
The C155 fuel gauge IC stores a discharge curve built from the old cell's characteristics. When a new cell goes in, the stored curve no longer matches actual cell behaviour, so displayed percentages are inaccurate — often reading high early and dropping fast near the end. The fix is one full charge-to-discharge cycle without interruption. This gives the coulomb counter enough data to rebuild its reference curve against the new cell. After that cycle, percentage readings stabilise and track correctly through normal use.