Ecovacs DSX39 Replacement Battery 14.4V 5200mAh Li-ion

Ecovacs DSX39 / T30S OMNI / DEEBOT X8 Pro OMNI — 14.4V Li-ion Replacement Battery (S31-LI-144-6400)

This is a 14.4V, 5200mAh (74.88Wh) lithium-ion battery for the Ecovacs DSX39, T30S OMNI, T30S Pro, and DEEBOT X8 Pro OMNI robotic vacuum cleaners. It replaces OEM part numbers S31-LI-144-6400, 201-2361-0022, and 201-2417-2394. When the original cell degrades and the robot stops completing full cleaning cycles, this is the direct swap.

• DSX39 / T30S / DEEBOT X8 platform fit: These models share a common 14.4V battery rail, connector pinout, and BMS handshake protocol. The cell communicates state-of-charge data to the robot's control board — a compatible BMS is required for the charge indicator and auto-dock return to function correctly.
• Bench tested on actual hardware: We cycled this cell through charge, discharge, and dock-return sequences on a DSX39 unit. The BMS held cutoff at the correct low-voltage threshold and accepted a full charge without triggering a fault state on the robot's main board.
• Dock charging habit for these robots: Do not leave the robot sitting on the dock continuously between uses. These Ecovacs models trickle-charge when docked, and sustained low-current charging accelerates capacity fade in lithium cells. Charge to full, then remove from the dock until the next cleaning run.

Suction dropping before the battery indicator reaches low on the DSX39

The DSX39 measures battery state-of-charge by voltage, not by a fuel gauge IC. As the cell ages, internal resistance rises and voltage sags under motor load — even when the indicator still shows mid-charge. The robot's motor controller interprets this voltage sag as a power deficit and reduces fan speed to protect the circuit. A fresh cell with lower internal resistance restores the voltage headroom the motor needs to sustain full suction through an entire cleaning map.

Robot cutting out mid-clean and recovering after sitting for a minute

This is a BMS overcurrent trip, not a power-off event. When suction is restricted — typically a blocked filter or tangled brush roll — the motor draws above its rated current ceiling. The BMS cuts output to protect the cell, the robot stops, and after the overcurrent clears, it restarts. The fix is to clean the filter and clear the brush roll before concluding the cell is faulty. If the trip occurs again on a clean filter with a new battery, check the brush roll bearing for resistance that forces the motor to work harder than spec.