Nihon Kohden WEE-1000 Compatible Battery 7.4V 3400mAh

Nihon Kohden WEE-1000 — 7.4V Li-ion Replacement Battery (X231 / YZ-03080)

This 7.4V, 3400mAh (25.16Wh) Li-ion battery replaces the OEM X231 / YZ-03080 cell in the Nihon Kohden WEE-1000 portable defibrillator. The WEE-1000 is a medical-grade AED used in emergency cardiac resuscitation — battery condition directly affects device readiness. Capacity and voltage figures match the OEM specification exactly.

• WEE-1000 fitment: The WEE-1000 uses a dedicated battery bay with a keyed connector and BMS handshake tied to the X231 / YZ-03080 cell profile. This replacement matches that voltage rail and connector geometry, so the device recognises the pack and proceeds through its startup verification sequence normally.
• Bench tested on actual hardware: We cycled this cell through the WEE-1000's charge and self-test routine. The BMS accepted the pack on first insertion, completed voltage verification without fault codes, and the charge IC brought the cell to full capacity within the device's expected charge window.
• Post-swap self-test protocol: After fitting this battery, allow the WEE-1000 to complete its full power-on self-test without interruption. The device runs BMS verification at startup — cutting power during this sequence triggers a persistent battery fault flag that will not clear until the next full, uninterrupted reboot.

WEE-1000 self-test failure after battery swap

The WEE-1000's BMS runs a learn cycle on first use to calibrate against the installed cell's actual charge curve. A new cell that hasn't completed one full charge-discharge cycle will present a slightly non-standard voltage profile, which the device may flag as a self-test fault. This is not a defective battery — it's the BMS applying its OEM-chemistry verification threshold before the cell has settled. Run one complete charge cycle from flat to full inside the device, then allow the self-test to complete. After that first cycle, the BMS recognises the cell and the fault clears.

Charge indicator stalls below 100% on the first charge

On the first charge, the WEE-1000's charge IC applies a conservative current limit to an unrecognised cell — the indicator may plateau at 90–95% and hold there longer than expected. This is the charge controller applying a slow top-up phase while it maps the new cell's internal resistance. Do not interrupt the charge. Leave the device on charge until the indicator advances to 100% and the ready signal activates — this typically requires the cell to reach at least 8.3V at the pack terminals to satisfy the charge-complete threshold.