ETA 5229 Master 14.4V Cordless Vacuum Replacement Battery 5200mAh

ETA 5229 Master / 6240 Twins — 14.4V Li-ion Replacement Battery (624000040)

This is a 14.4V, 5200mAh Li-ion replacement battery for the ETA 5229 Master, 6240 Twins, and 6229 Master Pro II cordless vacuums. OEM part numbers 624000040 and ICR-26J-4S2P-V3 confirm the fit. Capacity and voltage match the original cell pack specification from the product data.

• 5229 Master, 6240 Twins, 6229 Master Pro II compatibility: These three models run the same 14.4V cell architecture and share an identical BMS connector pinout. The battery management system handshake is consistent across the platform, so the same pack works without modification across all three vacuums.
• Bench tested on actual hardware: We cycled this pack through repeated motor-start loads and sustained suction draws. The BMS held voltage within spec under both filter-restricted and unobstructed airflow conditions, with no overcurrent trips recorded during normal operating load.
• Dock charging behaviour on ETA cordless vacuums: Do not leave the vacuum sitting on the charging dock continuously between uses. The ETA dock does not cut trickle current after full charge is reached, and sustained low-current input causes measurable cell capacity fade over weeks. Charge to full, then remove from the dock.

Suction dropping before the battery indicator shows low

The ETA 5229 Master motor draws significantly more current when the filter is partially blocked. Under restricted airflow, the motor works harder, voltage sags across the cell pack, and suction drops noticeably — even though the battery indicator still reads mid-range. The BMS reads pack voltage, not motor load, so it will not flag low battery during a voltage sag caused by restriction. Clean or replace the filter first before attributing the suction loss to the battery.

Motor cuts out mid-clean and then recovers after a few seconds

This is a BMS overcurrent trip, not a dead battery. When airflow is restricted — blocked filter, full dust cup, or a hard-surface blockage at the nozzle — the motor draws above the BMS overcurrent threshold, and the pack shuts the circuit. After a few seconds the BMS resets and power returns. If this repeats consistently, clear the blockage and check that the dust cup is emptied. A healthy pack running on a clean, unobstructed vacuum should hold above 12.5V under full motor load without tripping.