Cecotec Conga 8090 Replacement Battery 14.4V 5200mAh

Cecotec Conga 8090 Series — 14.4V Li-ion Replacement Battery (U099-4S1P / U099-4S2P)

This 14.4V, 5200mAh (74.88Wh) Li-ion battery replaces the original cell in the Cecotec Conga 8090, Conga 8090 Ultra, Conga 8090 Ultra T, and Conga 8090 Ultra X robotic vacuum cleaners. It matches the OEM voltage rail and connector geometry for those models. Fit the replacement and the robot picks up where the degraded original left off.

• Conga 8090 platform fit: The 8090, 8090 Ultra, 8090 Ultra T, and 8090 Ultra X all share the same battery bay dimensions and 14.4V power architecture. The U099-4S1P and U099-4S2P part numbers cover both single and double parallel cell configurations at the same nominal voltage, so the BMS handshake and connector remain consistent across variants.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Conga 8090 platform and confirmed the BMS completed a full charge cycle without fault codes. The protection circuit responded correctly to load spikes from the brush motor engaging on carpet transitions.
• Dock charging behaviour on the Conga 8090: Do not leave the robot sitting on the dock indefinitely between cleans. The Conga 8090 dock delivers a trickle charge once the battery reaches full — prolonged trickle charging accelerates cell degradation faster than standard cycle wear. Charge to full, then lift the unit off the dock.

Suction dropping before the battery indicator shows low on the Conga 8090

This happens when the brush motor draws above its rated current — usually caused by a partially blocked filter or tangled brush roll — and the battery voltage sags under that elevated load. The BMS reads the sag as low cell voltage and throttles power to the motor before the indicator reaches the low-battery threshold. The robot appears to be losing battery when it is actually reacting to a restricted airflow path. Clean the HEPA filter and clear the brush roll, then recheck — suction should stabilise well above the low indicator.

Motor cuts out mid-clean then restarts on its own

This is a BMS overcurrent trip, not a battery fault. When the brush motor stalls — against a rug edge, a cord, or a clogged intake — current draw spikes sharply and the BMS opens the output circuit to protect the cells. The robot pauses, the BMS resets after a few seconds, and the motor restarts. If this happens repeatedly in the same area, the motor is hitting a sustained restriction. Clear the obstruction, check that the filter is clean, and confirm no debris is jammed in the brush bearing before resuming the clean cycle.