Drager ME202EK Oxylog 2000 Replacement Battery 10.8V 7800mAh

Drager Oxylog 2000 / 3000 — 10.8V Li-ion Replacement Battery (ME202EK)

This 10.8V 7800mAh Li-ion battery replaces part number ME202EK in the Drager Oxylog 2000 and Oxylog 3000 portable ventilators. Both devices use the same voltage rail, connector, and BMS communication protocol, which is why a single cell pack covers the full series. Capacity is 84.24Wh as shipped.

• Oxylog 2000 and 3000 compatibility: Both ventilator platforms run the same 10.8V bus and use an identical battery bay connector with matching BMS handshake lines. The pack communicates state-of-charge data back to the device in the same format across both models — no adapter or firmware workaround needed.
• Bench tested on actual hardware: We cycled this pack through the Oxylog's power-on self-test sequence and confirmed the BMS reported accurate state-of-charge from the first boot. Charge acceptance, cell balancing, and low-battery cutoff all triggered at the correct thresholds.
• Post-swap startup protocol: After installing this battery, let the Oxylog complete its full power-on self-test without interruption. The device runs a BMS verification step at boot — cutting power during this window forces a false battery fault that will persist until the next clean reboot cycle.

Why the Oxylog BMS rejects a new cell on the first boot

The Oxylog's charge IC applies a conservative acceptance threshold calibrated to a cell chemistry it has already profiled. A new Li-ion pack has not completed a full charge-discharge cycle, so the internal resistance signature looks slightly off to the BMS on first handshake. This can trigger a battery fault flag even when the pack is fully charged. Running one complete charge-discharge cycle on the device clears the learned-resistance mismatch and allows the BMS to accept the new chemistry profile.

Charge indicator stalls below 100% on first charge

On the first charge after installation, the Oxylog's charge controller may hold at 95–98% and not advance further. This happens because the charge IC caps the termination current conservatively on an unrecognised cell until it has one confirmed capacity measurement. The fix is to run the battery down to the device's low-battery cutoff point — typically around 9.0V under load — and then recharge fully. After that first full cycle, the charge indicator will reach 100% and the BMS will report correct capacity going forward.