About this replacement
IRIS ST4ex — 3.7V Li-ion Replacement Battery (2010-0014)
This is a 3.7V 1000mAh Li-ion replacement battery for the IRIS ST4ex portable vital signs monitor. It replaces OEM part number 2010-0014 and restores full device operation when the original cell has degraded. Capacity is rated at 3.7Wh, matching the ST4ex's original power specification.
- ST4ex platform fit: The ST4ex uses a dedicated single-cell Li-ion pack with a BMS handshake tied to its power-on self-test routine. This replacement uses the same cell chemistry and connector configuration so the device firmware recognises the pack during startup verification.
- Bench tested on actual hardware: We ran this cell through the ST4ex's startup sequence and monitored the BMS communication during self-test. The pack passed voltage threshold checks and the charge IC accepted a full charge cycle without flagging a fault.
- Post-swap startup protocol: After fitting this battery, let the ST4ex complete its full power-on self-test without interruption. The device runs a BMS verification step at boot — cutting power during this sequence triggers a false battery fault that can persist until the next full reboot cycle.
Why the ST4ex charge indicator stalls below 100% on first charge
The ST4ex charge IC applies a conservative current limit when it first sees a new cell. This is intentional — the IC runs a conditioning pass before it allows a full charge termination cycle. On the first charge, the indicator may sit at 95–99% for an extended period before completing. This is not a fault. Let the charge cycle finish naturally and the issue resolves from the second charge onward.
ST4ex displaying low battery alarm immediately after a confirmed full charge
The ST4ex BMS compares cell discharge curves against stored OEM reference data during operation. A new cell's curve does not match the learned profile until it has completed one full charge-discharge cycle. Until that cycle is complete, the BMS can misread state-of-charge and trigger a low battery alarm even at 3.6–3.7V open circuit. Run one full discharge under normal use, then recharge to 100% — the BMS recalibrates against the actual cell curve and the false alarm clears.