About this replacement
Medical Econet Compact 2 / Compact 3 — 11.1V Li-ion Replacement Battery (ICR18650-26F)
This 11.1V, 3400mAh Li-ion battery replaces part number ICR18650-26F in the Medical Econet Compact 2 and Compact 3 portable medical devices. It matches the original cell voltage and capacity to keep the device's power management system satisfied. Dimensions are 66.72 × 55.10 × 21.80mm — verify clearance before fitting.
- Compact 2 and Compact 3 compatibility: Both models share the same battery bay geometry, connector pinout, and BMS handshake protocol. The ICR18650-26F cell format is specified across this platform, so one part number covers both units without modification.
- Bench tested on actual hardware: We cycled this battery through charge, standby, and load draw on compatible hardware. The BMS accepted the cell, completed its verification handshake, and held voltage within the expected 11.1V nominal band throughout discharge.
- Post-installation self-test protocol: After fitting, allow the device to complete its full power-on self-test cycle without interruption. Medical Econet devices run a BMS verification sequence at startup — cutting power during this window writes a battery fault flag that persists until the next complete reboot.
Why the Compact 2 triggers a low-battery alarm on a freshly charged cell
The Compact 2's BMS stores charge-cycle history against the OEM cell's electrochemical profile. A new replacement cell has no history, so the BMS applies conservative capacity estimates on the first cycle. This can push the calculated state-of-charge below the alarm threshold even when the cell is genuinely full. One complete charge-discharge cycle allows the BMS to calibrate against the actual cell behaviour and clears the false alarm state.
Device will not power on after the battery sat in storage
Li-ion cells self-discharge during storage. If the cell voltage drops below approximately 2.5V per cell — around 7.5V at the pack level — the Compact 2's BMS enters a protection lockout and will not allow a standard charge cycle to begin. Connect the device to mains power and leave it for at least 30 minutes before attempting to power on; the charger IC applies a low-current pre-charge trickle that brings the pack back above the BMS recovery threshold. Once the pack reaches 9V, normal charging resumes.