Eppendorf Response 4850 Pipette Controller Compatible Battery 6V 150mAh

Eppendorf Response Model 4850 — 6V Ni-MH Replacement Battery

This is a 6V 150mAh Ni-MH rechargeable cell for the Eppendorf Response Model 4850 motorized pipette controller. It replaces the internal battery that powers the motor drive and control electronics in this lab liquid-handling device. Dimensions are 30.00 × 24.72 × 14.26 mm — confirm these against your existing cell before ordering.

• Response Model 4850 fit: The 4850 uses a single compact Ni-MH pack at 6V to run both the aspiration motor and the onboard control logic. Voltage and physical footprint must match exactly — swapping chemistry or size breaks the charge circuit.
• Bench tested on actual hardware: We cycled this cell through the 4850's charge and discharge profile. The BMS accepted the cell without fault flags, and the charge IC brought the pack to full without triggering over-voltage cutoff.
• Power-on self-test protocol: After fitting this cell, let the 4850 complete its full startup self-test without interrupting power. The device runs a BMS verification pass at boot — cutting power mid-sequence locks in a false battery fault that won't clear until the next clean reboot.

Why the 4850 charge indicator stalls below 100% on a new cell

The 4850's charge IC applies a conservative current limit when it detects a cell with low initial voltage — typical on a new Ni-MH pack that has partially self-discharged in storage. The IC interprets the slow voltage rise as a degraded cell and caps the charge termination point early. Run one full charge-discharge cycle after first installation. On the second charge, the IC recalibrates its delta-V cutoff and the indicator reaches 100% correctly.

Device won't power on after the replacement cell sat in storage

Ni-MH cells self-discharge at roughly 1–2% per day in storage. If this battery has been sitting for several weeks before fitting, its resting voltage may be below the 4850's BMS recovery threshold — typically around 4.8V for a 6V pack. The BMS refuses to boot rather than risk operating with an undercharged cell. Place the device on charge for a full uninterrupted cycle before attempting power-on; the charger will recover the cell from low-voltage state before the BMS re-enables the power rail.