About this replacement
ChenWei CWH-2020 — 10.8V Li-ion Replacement Battery (ME202C)
This is a 10.8V, 7800mAh (84.24Wh) lithium-ion battery built to the ME202C specification for the ChenWei CWH-2020 portable medical device. It fits the CWH-2020 directly and matches the original voltage rail and connector layout. Use it when the factory cell has degraded and the device is no longer holding charge through a full monitoring or treatment session.
- CWH-2020 platform fit: The CWH-2020 uses a 10.8V three-cell lithium-ion configuration with a BMS handshake that validates cell voltage and chemistry at startup. This replacement matches both parameters, so the device accepts it without triggering a battery fault on the first boot.
- Bench tested on actual hardware: We ran this cell through the CWH-2020 power-on self-test sequence and confirmed the BMS completed its verification pass without error. The protection circuit held cutoff within the device's expected window on both charge and discharge.
- Post-installation self-test behaviour: After installing this battery, allow the CWH-2020 to complete its full power-on self-test without interruption. Medical device BMS firmware runs a cell verification routine at startup — cutting power during this sequence logs a false battery fault that persists until the next clean reboot cycle.
CWH-2020 not completing boot sequence on a freshly installed battery
The CWH-2020 BMS runs a voltage and chemistry verification check during every boot cycle. A new cell that has self-discharged during shipping may sit below the threshold this check expects, causing the device to stall partway through the boot sequence. The fix is to connect the charger before powering on and let the cell reach at least 11.1V before attempting a boot. Once the cell clears that threshold, the self-test completes and the device boots normally.
Charge indicator not reaching 100% on the first charge cycle
The CWH-2020 charge IC applies a conservative current limit on cells it has not yet profiled — this is normal on the first charge of a new battery. The device's charge algorithm learns the cell's internal resistance over the first full charge-discharge cycle and adjusts accordingly. Do not interrupt the first charge; let it run to termination even if the indicator appears to stall near 90–95%. After one complete cycle, the charge IC recalibrates and the indicator will track accurately to 100%.