Deik MT820 Cordless Vacuum Compatible Battery 14.4V 2600mAh

Deik MT820 — 14.4V Li-ion Replacement Battery

This is a 14.4V, 2600mAh lithium-ion battery pack for the Deik MT820 cordless stick vacuum. It replaces the original pack when capacity has faded or the battery no longer holds a charge. Voltage and connector match the MT820's motor drive circuit directly.

• MT820 platform fit: The MT820 runs a brushed DC motor on a 14.4V rail. This pack matches that rail exactly — drop to a lower voltage and the motor controller under-performs; go higher and you risk tripping the thermal fuse on the PCB.
• Bench tested on actual hardware: We cycled this pack through load and recovery on a 14.4V vacuum motor rig. The BMS held cutoff at the correct low-voltage threshold and recovered cleanly after a rest period with no fault latching.
• Dock charging behaviour on the MT820: Do not leave the MT820 sitting on its charging dock permanently. Continuous trickle current after full charge compresses the cell cycles faster than normal use does. Charge the pack fully, then remove the vacuum from the dock until the next session.

Suction dropping before the battery indicator reaches low on the MT820

This happens because the motor is drawing more current than rated — usually caused by a partially blocked filter or a restricted brush-roll, not a failing battery. Under high current draw, the cell voltage sags early and the motor loses torque before the indicator registers a low-battery condition. Clean the filter first. If suction recovers immediately after cleaning, the battery was not the problem. If the sag continues on a clean filter, the pack has lost usable capacity and replacement is the correct next step.

MT820 motor cuts out mid-use then restarts after a short pause

This is a BMS overcurrent trip, not a mechanical fault. When suction is restricted — blocked nozzle, saturated filter, or tangled brush-roll — the motor strains harder and pulls current past the BMS trip threshold. The BMS cuts power to protect the cells, then resets after a rest. Clear the blockage before assuming the battery is faulty. If cut-outs continue on an unobstructed, clean vacuum, measure resting pack voltage — anything below 12.5V after a full charge indicates the cells are no longer holding capacity.