About this replacement
Spacelabs EVO 4 — 3.7V Li-Polymer Replacement Battery (050-0517-00)
This 3.7V, 1200mAh lithium-polymer battery fits the Spacelabs EVO 4 and EVO portable patient monitors. It replaces OEM part numbers 050-0517-00 and 146-0140-00. The EVO 4 is a clinical vital signs monitor, and this cell maintains device operation during bedside and transport monitoring sessions.
- EVO 4 and EVO platform compatibility: Both the EVO and EVO 4 share the same battery bay geometry, connector pinout, and BMS communication protocol. The same cell services both units without modification.
- Bench tested on actual hardware: We cycled this battery through charge and discharge on the EVO 4 platform. The BMS accepted the cell, completed its initialisation handshake, and reported charge state accurately after the first full cycle.
- Post-swap self-test protocol: After fitting a new cell, allow the EVO 4 to complete its full power-on self-test without interruption. The device runs BMS verification at startup — cutting power mid-sequence triggers a false battery fault that persists until the next clean reboot.
Device not completing boot sequence on a freshly installed battery
The EVO 4 runs a hardware self-test at every startup, and the BMS checks cell voltage against a minimum threshold before releasing power to the display and sensor modules. A new cell shipped in a partial state of charge can sit just above or below this threshold, causing the monitor to stall mid-boot. If the device halts before reaching the main monitoring screen, connect the charger, allow the cell to reach full charge, then power on again. Do not interrupt the boot sequence once it begins.
Low battery alarm triggering immediately after a confirmed full charge
The EVO 4's BMS applies OEM-calibrated thresholds to assess cell state. A new replacement cell has not yet completed a learn cycle, so the BMS may misread capacity and trigger a low battery alarm even at full charge. This is a calibration issue, not a cell fault. Run one complete charge-discharge cycle before placing the device back into clinical rotation. After that cycle, the BMS recalibrates its state-of-charge reading and the alarm clears at the correct threshold — typically above 3.5V under load.