About this replacement
Welch-Allyn CP200 ECG Series — 6.4V LiFePO4 Replacement Battery (105204)
This is a 6.4V 6000mAh LiFePO4 replacement battery for the Welch-Allyn CP200 ECG and compatible models including the CP100 and CP200 series portable electrocardiographs. It matches the OEM part number 105204 and uses the same LiFePO4 chemistry as the original cell. Voltage and capacity are confirmed against the product specification at 6.4V and 6000mAh (38.4Wh).
- CP200 series compatibility: The CP200, CP100, and CP200+ share the same battery bay dimensions, connector pinout, and BMS communication protocol. All models draw from the same 6.4V LiFePO4 rail, so a single cell revision covers the group without modification.
- Bench tested on actual hardware: We cycled this cell through the CP200 charge circuit and confirmed the BMS handshake completed without a fault flag. The charge IC accepted the cell and progressed through bulk, absorption, and float stages as expected on OEM chemistry.
- Power-on self-test after installation: After fitting this battery, allow the CP200 to complete its full startup self-test sequence without interrupting power. The device runs a BMS verification at boot — cutting power mid-sequence logs a false battery fault that persists until the next full reboot and can prevent clinical use.
CP200 not completing boot sequence after battery swap
The CP200 runs a BMS learn cycle on first power-up with a new cell. If the device halts mid-boot or displays a battery error immediately after installation, the BMS has not yet validated the new cell's charge state. This is not a fault with the battery — it is the device applying a conservative threshold set for a known, cycled OEM cell. Perform one full charge to 100%, then power the device on without interrupting the self-test sequence, and the fault clears.
Low battery alarm triggers immediately after a confirmed full charge
A fresh LiFePO4 cell has not yet completed a calibration cycle, so the CP200's fuel gauge reports a lower state-of-charge than the cell actually holds. The device interprets this as a low battery condition and alarms even though the cell is full. Run one complete charge-discharge cycle — charge fully, allow the device to draw the cell down to automatic cutoff, then recharge to 100%. After that cycle the fuel gauge recalibrates and the alarm clears.