UONI S1 Replacement Battery 14.4V 6700mAh Li-ion

UONI S1 / V980 Series — 14.4V Li-ion Replacement Battery

This is a 14.4V, 6700mAh (96.48Wh) lithium-ion battery for the UONI S1, V980 Max, V980 Plus, and V980 Pro cordless stick vacuums. It replaces the original pack when capacity has dropped and the vacuum no longer holds a useful charge. Same voltage, same connector, same BMS interface as the factory cell.

• S1 and V980 series compatibility: These models share the same 14.4V battery bay, connector pinout, and BMS communication protocol. One battery fits all four variants without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the V980 platform. The BMS correctly negotiated with the charger, held the 14.4V nominal rail under motor load, and triggered overcurrent protection when airflow was deliberately blocked — exactly as the original pack does.
• Dock charging behaviour on UONI vacuums: Do not leave the vacuum sitting on the charging dock continuously. UONI's dock does not cut trickle current once the cell hits 100%. Leaving it docked around the clock accelerates capacity fade. Charge to full, then remove it from the dock.

Suction dropping before the battery indicator shows low

This happens when the motor draws more current than the BMS expects — usually because a partially clogged filter forces the motor to work harder against restricted airflow. Under that extra load, the cell voltage sags below the motor controller's threshold before the fuel gauge registers as low. The vacuum feels like it's running out of charge, but the real cause is mechanical restriction. Clean or replace the HEPA filter first, then retest — suction should stabilise at higher capacity levels.

Motor cuts out mid-clean then comes back after a short pause

This is a BMS overcurrent trip, not a failing cell. When the filter is blocked or the brush roll is tangled with hair, current draw spikes beyond the pack's rated limit. The BMS shuts the output rail to protect the cells, then resets once temperature or current drops. It will keep tripping until the restriction is cleared. Remove the brush roll cover, clear any debris, and check that the post-motor filter is seated correctly before blaming the battery.