Klarstein M-288 Replacement Battery 14.4V 4000mAh Ni-MH

Klarstein M-288 / M-488 Cleanfriend — 14.4V Ni-MH Replacement Battery

This is a 14.4V, 4000mAh Ni-MH battery pack for the Klarstein M-288 and Cleanfriend Cleaner M-488 cordless stick vacuums. It replaces the original pack when capacity has faded or the unit no longer holds a charge. Dimensions are 179 × 51 × 52mm — confirm these against your existing pack before ordering.

• M-288 and M-488 compatibility: Both models run the same 14.4V cell stack with an identical connector and housing footprint, so one pack covers both units. The BMS inside manages cell balancing across the Ni-MH stack and handles overcurrent cutoff during high-draw cleaning passes.
• Bench tested on actual hardware: We cycled this pack through repeated charge and discharge sequences, confirming the BMS trips correctly under sustained overcurrent load and recovers cleanly once the draw returns to normal. Cell voltages balanced within spec across the full stack.
• Dock charging habit on this vacuum: Do not leave the M-288 or M-488 sitting on the charging dock permanently. Ni-MH cells on continuous trickle charge develop capacity fade significantly faster than cells charged only when depleted. Charge to full, then remove the unit from the dock.

Suction dropping before the battery indicator reaches low

On the M-288 and M-488, suction loss ahead of a low-battery warning is almost always a voltage sag issue rather than a failing cell. A partially blocked filter forces the motor to draw above its rated current. The BMS responds by throttling output voltage to protect the stack, which the user experiences as suction dropping off. Clear the filter first — if suction recovers immediately, the battery was not the cause.

Motor cuts out mid-clean then comes back on its own

This is a BMS overcurrent trip, not a wiring fault. When airflow is restricted — blocked filter, full dustbin, or a floor-head clog — the motor pulls a sustained current spike that exceeds the BMS threshold. The BMS cuts the circuit, the motor stops, and once current drops the BMS resets automatically. Fix the restriction first. If the cutouts continue with a clear filter and empty bin, verify battery voltage under load is holding above 12V.