About this replacement
Sony CMD-C1 / CMD-C8 — 3.7V Li-ion Replacement Battery (1HR14430)
This is a 3.7V, 650mAh Li-ion replacement battery for the Sony CMD-C1 and CMD-C8 mobile phones. It matches the OEM part number 1HR14430 and slots into the same battery bay without modification. Capacity figure is taken directly from the product specification — 2.41Wh.
- CMD-C1 and CMD-C8 compatibility: Both models share the same battery bay dimensions and 3.7V single-cell architecture. The connector pinout and BMS handshake protocol are identical across the two, so one cell covers both. No adapter or wiring change needed.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on CMD-series hardware. The BMS accepted charge handshake correctly, protection circuitry tripped at expected low-voltage cutoff, and the fuel gauge IC tracked state-of-charge without error flags after one full calibration cycle.
- Fuel gauge recalibration on first use: On first installation, disable any fast-charge mode and run one complete discharge-charge cycle at standard current. This lets the phone's fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.
Sudden shutdown at 20–30% on the CMD-C1 after a cell swap
This happens because the fuel gauge IC is still running the discharge curve from the old, degraded cell. The new cell has a steeper voltage cliff under load — modem transmit bursts and screen backlight together pull enough current to drop cell voltage below the BMS cutoff threshold before the percentage reading catches up. The phone reads 25% and cuts out because the actual cell voltage has already hit the 3.0V protection floor. Run one full discharge to auto-off and a full uninterrupted charge to reset the coulomb counter — after that cycle, the reported percentage tracks accurately.
Phone shows "charging" but percentage stays flat after replacement
A freshly manufactured Li-ion cell arrives with higher internal impedance than the cell it replaces. The charge IC sees this impedance and may throttle current significantly on the first charge session, making the percentage appear stuck. This is not a fault in the battery or the phone — it resolves as the cell undergoes its first formation cycle. Let the first charge run uninterrupted to 100% without removing the cable early. If the percentage is still flat after 90 minutes, check the charge connector pins for oxidation and verify the charger output is at least 5V 700mA.