Envitec 1001734 Medical Device Replacement Battery 3.7V 2600mAh

Envitec MySign S / MySign O O2 Meter — 3.7V Li-ion Replacement Battery (1001734)

This 3.7V, 2600mAh Li-ion cell replaces OEM part 1001734 in the Envitec 1001844, MySign O O2 Meter, and MySign S portable pulse oximeters. It matches the original voltage rail and connector footprint. Capacity is drawn from the product spec sheet — 9.62Wh total energy.

• MySign S and MySign O platform fit: Both devices share the same 3.7V single-cell architecture, BMS handshake protocol, and connector pinout — which is why one cell covers the full range. The BMS expects a flat discharge curve consistent with Li-ion chemistry; substituting a different chemistry type will trigger a false low-battery fault.
• Bench tested on actual hardware: We cycled this cell through charge and load on a MySign-series unit. The BMS accepted the cell without flagging a fault, completed the charge-termination handshake at 4.2V, and held the load through a full discharge sweep without tripping the protection circuit.
• Post-swap power-on sequence: After fitting this cell, let the device complete its full power-on self-test without interruption. MySign-series devices run a BMS verification check at startup — cutting power during that sequence locks in a false battery fault that persists until the next clean reboot.

Device not completing boot sequence after battery swap

MySign-series units run a BMS learn cycle during the first few charge-discharge sequences on a new cell. Until that cycle completes, the device may stall mid-boot or report an error state it wouldn't show on a conditioned OEM cell. This is a firmware-level response to an unrecognised charge profile, not a fault with the cell itself. Run one full charge to 4.2V, then allow a full discharge under normal use before treating any boot error as a hardware fault.

Charge indicator not reaching 100% on first charge

On the first charge cycle, the MySign charge IC applies a conservative current limit to an unrecognised cell — this causes the indicator to plateau below 100% and stay there. The cell is not defective; the charge controller is running a cautious first-pass profile. Disconnect, power the device on fully, let it run down, then recharge from below 3.5V. The second charge cycle typically reaches full termination voltage without issue.