About this replacement
Carewell ECG-1101 Series — 12V Ni-MH Replacement Battery (88889089)
This 12V 2000mAh Ni-MH battery replaces part number 88889089 in the Carewell ECG-1101, ECG-1101G, and ECG-1101B portable electrocardiogram monitors. These handheld devices are used for cardiac rhythm monitoring in clinical and home settings. Voltage, connector, and BMS handshake match the original specification.
- ECG-1101, ECG-1101G, and ECG-1101B compatibility: All three variants share the same 12V power rail, physical form factor, and BMS communication protocol, which is why a single cell supports the full model range. The connector pinout and charge IC signalling are identical across the series.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the ECG-1101 platform. The BMS accepted the new cell on first insertion, completed its verification handshake, and held voltage within tolerance across the full discharge curve.
- Power-on self-test after installation: Once installed, let the device run its full startup self-test without interruption. The ECG-1101 runs a BMS verification sequence at boot — cutting power mid-sequence logs a false battery fault that persists until the next clean reboot cycle.
Why the ECG-1101 flags a battery fault on a fully charged new cell
The ECG-1101's BMS uses a learned chemistry profile to validate cell state at startup. A new Ni-MH cell has not yet established the charge/discharge curve the BMS expects from a conditioned cell. Until one full charge-discharge cycle is complete, the BMS may flag a fault or show a lower-than-expected state of charge. Run one complete cycle before relying on the battery for clinical monitoring.
Charge indicator not reaching 100% on the first charge
On first charge, the ECG-1101's charge IC applies a conservative current limit to an unrecognised cell. This causes the indicator to plateau below 100% and sometimes stop advancing entirely. This is a charge IC behaviour, not a cell fault. Run the device down to automatic cutoff, then charge uninterrupted — the second charge cycle typically reaches full capacity and registers correctly on the display.