About this replacement
Fresenius SP7 / VP7 Syringe Pumps — 11.1V Li-Polymer Replacement Battery (KAYO654169-3S)
This 11.1V, 1900mAh Li-Polymer battery replaces the KAYO654169-3S cell pack in Fresenius SP7 and VP7 syringe pumps. These portable volumetric infusion pumps operate in clinical environments where power continuity directly affects medication delivery accuracy. Match voltage and chemistry exactly before fitting — the pump's BMS enforces strict cell-type validation at startup.
- SP7 and VP7 platform compatibility: Both models share the same battery bay dimensions, connector pinout, and 11.1V three-cell Li-Polymer architecture. The BMS communicates over the same data line, so one cell pack covers the full listed range without modification.
- Bench tested on actual hardware: We cycled this pack through full charge-discharge runs and monitored BMS handshake signals. The protection circuit responded correctly to charge termination at cell voltage ceiling and flagged low-battery status at the expected depletion threshold.
- Post-installation self-test protocol: After fitting this battery, allow the SP7 to complete its full power-on self-test without interruption. The pump runs BMS verification during boot — cutting power mid-sequence triggers a persistent false battery fault that survives subsequent charge cycles and clears only on a clean reboot from full charge.
Why the SP7 rejects a new battery during its startup self-test
The SP7's BMS compares cell chemistry signatures against stored OEM parameters on every boot. A fresh Li-Polymer cell has a slightly different impedance profile than a conditioned pack, and the pump's charge IC can flag this as an unrecognised or degraded source. This is not a fault with the replacement cell — it is a calibration gap. One complete charge-discharge cycle normalises the impedance signature and allows the BMS to pass the cell through self-test without error on subsequent startups.
Charge indicator stalls below 100% on first charge after swap
On a fresh cell, the SP7's charge controller applies a conservative current ceiling during the final constant-voltage phase, which extends the time the indicator spends climbing through the last 5–10%. This is the charge IC protecting new cell chemistry during the first cycle, not a sign of a faulty pack. Do not interrupt the charge at this point — let the cycle complete fully. After the first full charge, the indicator will track accurately against actual cell state.