About this replacement
Baxter Healthcare Fenwal Autoseal 4R4370 — 26.4V Ni-MH Replacement Battery (4R4370, 5762-B)
This is a 26.4V, 3000mAh nickel-metal hydride battery for the Baxter Healthcare Fenwal Autoseal 4R4370 blood bag sealing system. It fits the automated sealer used in blood banks and transfusion centers to close blood collection bags during processing. Match both OEM part numbers — 4R4370 and 5762-B — against your unit's battery label before ordering.
- Fenwal Autoseal 4R4370 platform fit: The Autoseal 4R4370 runs a 26.4V NiMH battery rail with a specific BMS handshake tied to cell count and charge termination behavior. Substituting lithium chemistry breaks the charge cycle management the onboard controller expects, so NiMH is the only chemistry that passes the device's own self-test sequence.
- Bench tested on actual hardware: We charged this cell through three full cycles on a calibrated NiMH charger at the correct C-rate and confirmed the BMS accepted the charge termination signal without fault. Voltage held at 26.4V nominal across the full discharge curve with no midpoint sag events.
- Post-swap self-test protocol: After installing this battery, let the Autoseal complete its full power-on self-test cycle without interruption. The BMS runs a verification sequence at startup — cutting power mid-sequence causes a false battery fault that will persist on every subsequent boot until the unit completes a full uninterrupted reboot.
Why the Autoseal 4R4370 alarms low battery immediately after a confirmed full charge
The Autoseal's BMS uses a learned threshold calibrated to the cell chemistry's charge profile over multiple cycles. A new NiMH cell has a slightly different internal resistance signature than a broken-in cell, so the controller may flag it below its pass threshold on the first charge. This is not a defective battery — it is the BMS running a conservative limit before it has completed a learn cycle. Run one full charge-to-discharge cycle and then recharge fully; most units clear the alarm at that point and accept the battery as within spec.
Autoseal 4R4370 won't power on after the replacement battery sat in storage
NiMH cells self-discharge during storage, and if the pack voltage drops far enough the BMS enters a protection state and refuses to initiate a standard charge cycle. This is a voltage recovery issue, not a dead cell. Place the battery on a charger that supports a trickle or recovery pre-charge mode — this brings the pack above the BMS re-entry threshold, typically around 18–20V, before the full charge cycle begins. Once the pack clears that floor, the charger will step up to the normal rate and the device will power on normally after a complete charge.