About this replacement
Mindray SP1 Series — 7.4V Li-ion Replacement Battery (ICR18650-2S)
This 7.4V, 3400mAh Li-ion battery replaces the ICR18650-2S (OEM ref 115-068528-00) in the Mindray SP1 portable patient monitor. It also fits the SP1 Syringe Pump, SK-801 EX, BeneFusion VP3, and eleven additional models sharing this voltage rail and connector format. Capacity matches the original at 3400mAh (25.16Wh).
- Multi-model compatibility across SP1 and BeneFusion platforms: These devices share a common 7.4V two-cell configuration, identical connector pinout, and the same BMS communication protocol — which is why one cell fits across all listed models without modification.
- Bench tested on actual hardware: We ran full charge and discharge cycles on this cell, confirming the BMS handshake completes correctly and protection thresholds — overcurrent, over-temperature, and low-voltage cutoff — trigger within spec.
- Post-installation self-test on Mindray SP1: After fitting this battery, allow the device to complete its full power-on self-test without interruption. The SP1 runs a BMS verification sequence at startup — cutting power during this window logs a false battery fault that persists until the next clean reboot.
Why the SP1 alarms low battery immediately after a confirmed full charge
The SP1's charge IC applies conservative acceptance thresholds calibrated to the OEM cell's internal resistance profile. A new third-party cell has a slightly different impedance signature, so the BMS can flag it as below threshold on the first cycle even when the cell is fully charged. This is not a fault — it resolves after one complete charge-discharge cycle, which lets the BMS learn the new cell's characteristics. Run that cycle before returning the device to clinical use.
SP1 will not power on after the battery sat in storage
Li-ion cells self-discharge during storage, and if the pack drops below roughly 2.5V per cell (5.0V total), the BMS enters deep-discharge lockout and blocks output to protect the cells. The SP1 will show no response — no boot, no charging indicator. Connect the device to mains power and leave it for a minimum of 30 minutes before attempting to power on; the charger applies a trickle current that brings the pack above the BMS recovery threshold. If the indicator still does not respond after 60 minutes on charge, check the charger output at the connector — it should read between 8.2V and 8.4V.