Edan F6 Fetal Monitor Replacement Battery 14.8V 5200mAh

Edan F6 / F9 Fetal Monitor — 14.8V Li-ion Replacement Battery (TWSLB-006)

This is a 14.8V 5200mAh (76.96Wh) Li-ion battery for the Edan F6 and F9 fetal monitors. It replaces OEM part numbers TWSLB-006, HYLB-854, 4IXR19/65-2, and 21.21.064150. These are the portable fetal monitoring units used for continuous cardiotocography in obstetric and labor ward settings.

• F6 and F9 platform fit: Both models run the same 14.8V four-cell battery architecture with a shared BMS handshake protocol. The connector pinout and cell configuration are identical across the F6 and F9, which is why a single part number covers both units.
• Bench tested on actual hardware: We ran this cell through the F6 charge and discharge cycle. The BMS accepted the cell without fault, completed cell-balancing on the first full charge, and voltage held within the expected 16.8V–12.0V operating window under simulated monitoring load.
• Post-swap self-test protocol: After installation, allow the device to complete its full power-on self-test cycle without interruption. The F6 and F9 run a BMS verification routine at startup. Interrupting it during the first boot causes a latching battery fault that will not clear until the next complete reboot cycle.

Charge indicator not reaching 100% on the first charge after swap

The F6 charge IC applies a conservative current ceiling when it first encounters a new cell. This is normal behaviour — the charge controller is running a capacity estimation pass before allowing a full-rate charge. On the first cycle, the indicator may stall at 90–95% for an extended period. Let the charge cycle complete fully without disconnecting power. After one full charge-discharge cycle, the charge IC recalibrates and the indicator will reach 100% as expected on subsequent charges.

Device will not power on after replacement cell sat in storage

Li-ion cells self-discharge during storage. If the resting voltage drops below approximately 10.0V, the F6 BMS enters deep-discharge lockout and will not pass power to the device even when connected to the charger. Connect the unit to mains power and leave it on the charger for a minimum of 30 minutes before attempting to power on. The charge IC will trickle-charge the cell back above the BMS recovery threshold — typically around 10.8V — at which point normal charging and boot sequence will resume.