Eppendorf Easypet 3 Replacement Battery 3.7V 1050mAh

Eppendorf Easypet 3 — 3.7V Li-ion Replacement Battery (4430 605.009)

This 3.7V Li-ion cell replaces OEM part 4430 605.009 in the Eppendorf Easypet 3 motorized pipette controller. At 1050mAh (3.89Wh), it powers the drive motor used for liquid aspiration and dispensing in laboratory and clinical workflows. The physical footprint matches the original at 56.14 × 29.45 × 11.00mm for direct installation.

• Easypet 3 motor circuit compatibility: The Easypet 3 draws variable current depending on pipette tip size and fluid viscosity. This cell's internal resistance profile and 3.7V nominal voltage match the motor controller's expected supply — the BMS handshake proceeds without fault codes on insertion.
• Bench tested on actual hardware: We ran the cell through the Easypet 3 startup sequence and full aspiration cycles. The BMS accepted the new cell, completed its internal checks, and passed motor load draws without tripping overcurrent protection across repeated cycles.
• Post-installation self-test protocol: After fitting this cell, let the Easypet 3 complete its power-on self-test without interrupting it mid-cycle. The device runs a BMS verification at startup — cutting power during this sequence triggers a false battery fault that persists until the next clean reboot.

Charge indicator not reaching 100% on the first charge after installation

The Easypet 3 charge IC applies a conservative current ceiling on cells it hasn't previously profiled. On the first charge cycle with a new cell, the algorithm may terminate early or plateau below 100% — this is the charge controller being cautious, not a faulty cell. Run one complete charge-discharge cycle and the IC recalibrates its termination threshold. After that cycle, the indicator reaches full charge normally.

Easypet 3 shutting off unexpectedly during aspiration in the first week of use

New Li-ion cells have slightly elevated internal resistance before their electrode structure fully forms. The Easypet 3 motor draws a sharp current spike at the start of each aspiration stroke — in the first 10 cycles, that spike can push voltage momentarily below the BMS cutoff threshold, triggering a shutdown. This is not a defective cell; it self-corrects as the cell cycles. Run several full charge-discharge cycles before returning the device to clinical use, and check that the resting voltage reads at least 3.6V before each session.