Artfone C3 Replacement Battery 3.7V 900mAh Li-ion

Artfone C3 / CF241A / CS181 Series — 3.7V Li-ion Replacement Battery

This is a 3.7V, 900mAh Li-ion cell for the Artfone C3, CF241A, CS181, and CS181A handsets. These are senior-focused mobile phones with large buttons and a straightforward calling interface. The battery slots into the same compartment as the original and uses the same connector pinout.

• C3 / CF241A / CS181 platform fit: All four models in this family share the same battery bay dimensions (53.00 × 34.00 × 4.30mm), the same 3.7V charge voltage, and the same three-pin connector. One replacement cell covers the full range.
• Bench tested on actual hardware: We cycled this cell through a full discharge-charge sequence on the C3 handset. The onboard charge IC accepted the cell immediately, BMS protection trips functioned correctly at the low-voltage cutoff, and the fuel gauge initialised without errors.
• Fuel gauge recalibration on first use: After fitting, let the phone discharge fully until it powers off on its own, then charge uninterrupted to 100%. This gives the fuel gauge IC one complete reference cycle against the new cell's actual discharge curve before the percentage readout becomes trustworthy.

Why the C3 reports wrong battery percentage after a cell swap

The Artfone C3 uses a simple fuel gauge IC that tracks charge state by measuring voltage against a stored discharge curve calibrated to the original cell. A new cell has a slightly different internal resistance profile, so the IC's voltage-to-percentage mapping is off from the start. The displayed percentage can read 40% while the actual remaining capacity is much lower or higher. One full discharge-to-cutoff followed by an uninterrupted charge to 4.2V resets the reference and brings the readout back into line.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff — not a fault with the cell itself. Under the load of an active call, the modem draws a short burst of current that the uncalibrated gauge cannot predict. The cell voltage drops below the BMS protection threshold before the percentage counter catches up, and the phone cuts out. It typically happens before the first full recalibration cycle is complete. Run one complete discharge-charge cycle and the gauge learns the real voltage curve; the early shutdowns stop once it knows where the cliff actually sits.