CONTEC ECG-1200 Replacement Battery 14.8V 4000mAh 855183P-4S

CONTEC ECG-1200 / ECG-1200G — 14.8V Li-Polymer Replacement Battery (855183P-4S)

This is a 14.8V 4000mAh (59.2Wh) Li-Polymer replacement battery for the CONTEC ECG-1200 and ECG-1200G portable electrocardiograph. It matches OEM part number 855183P-4S and fits the physical bay and connector used on both variants. Capacity figures come from the product data — not web estimates.

• ECG-1200 and ECG-1200G compatibility: Both models run the same 14.8V four-cell Li-Polymer architecture and use the same BMS handshake protocol. The battery bay dimensions — 78.50 × 57.40 × 33.60mm — and the connector pinout are identical across both variants, which is why one part number covers both.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a 14.8V Li-Polymer bench rig. The BMS accepted the charge profile without fault, reported accurate state-of-charge data across the full range, and held voltage within spec under the low-draw load profile typical of portable ECG hardware.
• Post-swap startup protocol: After installing this battery, let the ECG-1200 complete its full power-on self-test without interrupting it. The device runs a BMS verification sequence at startup — cutting power mid-sequence causes a false battery fault flag that persists until the next complete reboot.

ECG-1200 not completing boot sequence after battery swap

The ECG-1200 runs a multi-stage power-on self-test that includes a BMS handshake check. If the battery cell voltage is slightly below the device's minimum boot threshold — common after shipping storage — the unit stalls mid-sequence or refuses to proceed past the initialisation screen. Charge the new battery to full before the first boot attempt. If the device still stalls, confirm the charger output is reaching 16.8V, which is the correct full-charge voltage for a 4S Li-Polymer pack at 14.8V nominal.

Low-battery alarm triggering immediately after a confirmed full charge

This happens because the ECG-1200's BMS compares the incoming cell's internal resistance profile against thresholds calibrated for the original OEM chemistry. A new replacement cell — even at full charge — can read as marginal on the first cycle until the BMS learns its actual capacity curve. Run one complete charge-discharge cycle before clinical use. After that first full cycle, the alarm threshold recalibrates and the false low-battery warning stops.