Ilife B5 Max 14.4V Replacement Battery 2600mAh 18650B4

Ilife B5 Max / Noisz S5 Pro / V3s Pro — 14.4V Li-ion Replacement Battery (18650B4-4S1P-AGX-2)

This is a 14.4V 2600mAh Li-ion battery pack for the Ilife B5 Max robotic vacuum and compatible models in the same voltage family. It replaces part numbers 18650B4-4S1P-AGX-2, 18650M26-4S1P-AGX-8, and SUN-INTE-202. It restores power to the vacuum's drive motors, suction fan, and navigation sensors when the original cell pack no longer holds a full charge.

• B5 Max, Noisz S5 Pro, V3s Pro, V5s compatibility: These models share a common 14.4V 4S1P cell architecture and the same physical connector and BMS handshake protocol. The same pack fits all of them because the motor rail and charging circuit spec are identical across this platform generation.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the B5 Max platform. The BMS responded correctly to the dock charger handshake, balanced cells within expected tolerance, and triggered overcurrent cutoff at the correct threshold under a blocked-impeller load test.
• Dock charging habit for robotic vacuums: Do not leave the B5 Max sitting on the dock continuously between uses. Robotic vacuums on permanent dock contact receive trickle charge that accelerates capacity fade in Li-ion cells. Charge fully, then remove the unit from the dock until the next scheduled run.

Suction dropping before the battery indicator reaches low

This happens when the suction motor draws more current than rated because airflow is restricted — most often a clogged filter or tangled brush roll. The battery voltage sags under the higher draw, and the vacuum's power management steps down motor speed before the fuel gauge registers low. The indicator is measuring state of charge, not real-time voltage under load, so the two don't match. Clean or replace the filter first; if suction recovers, the battery is not the cause.

Motor cuts out mid-clean and then recovers on its own

This is a BMS overcurrent trip, not a dead battery. When the brush roll jams on carpet fibres or debris, the motor stalls and current spikes past the BMS threshold — the pack shuts the output rail to protect the cells. After a few seconds the BMS resets and power returns. Clear the brush roll, check that the filter is not restricted, and retry. If trips continue on an open floor with a clean filter, check that the pack voltage reads at least 14.4V off the charger before reinserting.