Eufy RoboVac 11 Replacement Battery 14.8V 3400mAh

Eufy RoboVac 11 / 11S Series — 14.8V Li-ion Replacement Battery (PA04)

This 14.8V, 3400mAh Li-ion battery replaces the original pack in the Eufy RoboVac 11, 11S, 11S Max, RoboVac 12, and over 29 additional RoboVac models. It matches the OEM voltage, cell count, and connector used across the RoboVac 11 platform. Capacity is sourced from the product specification — 3400mAh (50.32Wh).

• RoboVac 11 platform compatibility: The RoboVac 11, 11S, and 11S Max share the same 14.8V four-cell Li-ion architecture and BMS handshake protocol. The connector, cell arrangement, and charge termination logic are consistent across these variants, which is why a single pack covers the full range.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on RoboVac 11 and 11S units. The BMS accepted charge termination correctly at 16.8V, and the protection circuit tripped as expected on simulated overcurrent — no fault codes, no thermal events.
• Dock charging discipline for RoboVac models: Remove the RoboVac from its dock once the charge indicator shows full. These models do not interrupt trickle current automatically when left docked long-term. Continuous dock sitting accelerates cell degradation faster than regular use cycles alone.

Suction dropping before the battery indicator reaches low

The RoboVac 11 series reduces motor speed when cell voltage sags under load — this happens before the low-battery LED triggers. A partially blocked filter or brush roll forces the motor to draw above its rated current, which causes the voltage across the cells to drop faster than normal. The BMS reads this as a low-charge condition and throttles output. Clean the filter and check the brush roll for hair tangles before assuming the battery is at fault.

RoboVac stops mid-cycle, then resumes after sitting for a few minutes

This is a BMS overcurrent trip, not a dead battery. When suction is restricted — blocked filter, full dustbin, or a mat caught in the brush — motor draw spikes and the protection circuit cuts output to prevent cell damage. The pack recovers once current demand drops, which is why the unit restarts after a short pause. Clear the blockage, empty the dustbin, and confirm the filter is seated correctly before the next cycle.