BrandTech accu-jet Replacement Battery 2.4V 2000mAh Ni-MH BT26531

BrandTech accu-jet Pipette Controller — 2.4V Ni-MH Replacement Battery (BT26531)

This is a 2.4V, 2000mAh Ni-MH replacement battery for the BrandTech accu-jet pipette controller. It replaces OEM part BT26531 and restores power to the electronic dispensing mechanism. Fits accu-jet models used in laboratory and clinical liquid-handling workflows.

• accu-jet platform fit: accu-jet controllers across the range share the same 2.4V Ni-MH cell format, connector pinout, and BMS handshake protocol. This cell matches that specification exactly — voltage, capacity, and physical dimensions (51.52 × 29.30 × 15.64 mm).
• Bench tested on actual hardware: We ran this cell on an accu-jet controller and confirmed the BMS accepted the new cell without fault flags. The charge IC completed its full cycle and the motor drive operated normally across aspiration and dispensing strokes.
• Post-swap self-test cycle: After inserting this battery, allow the accu-jet to complete its power-on self-test without interruption. The BMS runs a verification sequence at startup. Interrupting it before completion causes a false battery fault that persists until the next full reboot — it is not a cell defect.

Why the accu-jet charges slowly or stops short of full on the first cycle

The accu-jet charge IC applies a conservative current limit when it first sees a new Ni-MH cell. This is intentional — the controller uses delta-V detection to determine end-of-charge, and a fresh cell produces a flatter voltage curve than a conditioned one. The IC interprets this as an anomaly and terminates early. One full charge-discharge cycle normalises the cell's internal resistance profile, and subsequent charges reach rated capacity.

accu-jet cutting power mid-aspiration after the first few uses

New Ni-MH cells have slightly elevated internal resistance during the first 5–10 cycles. The accu-jet motor draws a short current spike at the start of each aspiration stroke. On an unconditioned cell, that spike causes a momentary voltage sag that crosses the BMS low-voltage cutoff threshold, tripping a shutdown. This is not a faulty battery — it resolves as internal resistance drops through normal cycling. Run three full charge-discharge cycles before clinical use to condition the cell and eliminate these cutoffs.