Fresenius Volumat Agilia VP Z179971 Replacement Battery 7.4V

Fresenius Volumat Agilia VP Version V2 — 7.4V Li-ion Replacement Battery (Z179971)

This 7.4V, 3400mAh lithium-ion battery is a direct replacement for the Fresenius Volumat Agilia VP Version V2 infusion pump. It fits the internal battery bay using OEM part numbers Z179971 and Z179985. Capacity is rated at 25.16Wh, matching the original cell specification.

• Volumat Agilia VP V2 platform fit: The VP Version V2 uses a specific BMS handshake tied to cell voltage and internal resistance thresholds. This battery matches the 7.4V nominal rail and the connector pinout the pump's charge controller expects. Cells sourced to the same capacity and discharge curve as the original chemistry grade.
• Bench tested on actual hardware: We cycled this battery through the Agilia VP V2's charge and discharge sequence on the bench. The BMS accepted the cell without flagging a chemistry mismatch, and the charge controller stepped through its normal taper phase without early cutoff.
• Post-swap self-test protocol: After installation, allow the pump to complete its full power-on self-test without interruption. The Agilia VP V2 runs a BMS verification routine at startup — cutting power during this sequence causes a false battery fault that latches until the next clean reboot.

Why the Agilia VP V2 alarms low battery immediately after a confirmed full charge

The pump's BMS stores a learned capacity model from the previous cell. When a new battery is installed, the internal resistance profile and open-circuit voltage curve differ slightly from the stored baseline. The BMS interprets this as a degraded cell and triggers a low battery alarm before the learn cycle completes. One full charge-discharge cycle on the new cell allows the BMS to update its reference and clear the alarm state.

Pump fails to complete boot sequence after battery sat in storage

Li-ion cells self-discharge during storage. If a replacement battery drops below the Agilia VP V2's BMS recovery threshold — typically around 2.5V per cell — the pump will not draw enough current at startup to complete its boot sequence. Connect the pump to mains power and leave it on charge for at least two hours before attempting to power on from battery alone. The charge IC will apply a pre-charge conditioning current to bring the cell voltage back above the recovery threshold before switching to normal charge rate.