Medion HJ08 14.4V Cordless Vacuum Replacement Battery 2600mAh

Medion MD18500 / MD18501 Series — 14.4V Li-ion Replacement Battery (HJ08)

This is a 14.4V 2600mAh Li-ion battery for the Medion MD18500, MD18501, MD18600, and MD19510 cordless handheld vacuum cleaners. It replaces OEM part numbers HJ08 and HA15. Fit it when the original battery no longer powers the motor through a full cleaning session or refuses to take a charge.

• MD18500 / MD18501 / MD18600 / MD19510 platform fit: These models share the same 14.4V battery rail, connector pinout, and BMS handshake protocol — one cell pack covers the full range. The BMS on each model communicates state-of-charge data over the same signal line, so the replacement integrates without recalibration.
• Bench tested on actual hardware: We cycled this cell pack through load tests replicating the MD18500 motor draw on carpet and hard floor modes. The BMS held voltage within spec under sustained suction load and triggered overcurrent protection correctly when the airpath was blocked.
• Dock charging discipline on the MD18500: These vacuums sit on a wall-mount charging dock between uses. Leaving the pack on the dock continuously after it reaches full charge accelerates capacity fade — the trickle current degrades the cells faster than normal cycling. Charge to full and remove it from the dock.

Suction dropping before the battery indicator shows low

The motor in the MD18500 draws more current when airflow is restricted — a dirty filter or blocked nozzle can push draw well above normal operating levels. The BMS responds by reducing output voltage to stay within safe limits, which the user feels as a sudden drop in suction power. The battery indicator reads the cell voltage at rest, not under load, so it can still show two bars while the pack is already sagging under motor demand. Clean the filter first; if suction remains weak with a clean airpath, the original pack has likely lost capacity and needs replacing.

Motor cuts out mid-use then restarts after a few seconds

This is a BMS overcurrent trip — not a failed battery. It happens when sustained high motor draw, usually from a partially blocked filter or a tangle around the brush head, pushes current above the pack's rated threshold. The BMS trips, cuts output, waits for the cell temperature and current to fall, then resets. Clear the blockage and check the filter before putting the vacuum back into service. If the cutouts continue on a clean, unobstructed airpath, measure pack voltage under load — it should hold above 12.5V during normal operation.