AlfaBot T30 Cordless Vacuum Compatible Battery 25.2V 4500mAh

AlfaBot T30 / T36 — 25.2V Li-ion Replacement Battery

This is a 25.2V, 4500mAh lithium-ion replacement battery for the AlfaBot T30 and T36 cordless stick vacuums. It slots into the same battery bay as the original and runs the same motor voltage rail. Capacity is drawn from product data: 4500mAh / 113.4Wh.

• T30 and T36 compatibility: Both models share the same 25.2V battery platform, connector pinout, and BMS handshake protocol. A single cell covers both units without modification.
• Bench tested on actual hardware: We ran this battery through motor-start and sustained suction cycles. The BMS handled inrush current on startup without tripping and held voltage stable across simulated floor and carpet loads.
• Dock charging behaviour: Do not leave the T30 or T36 sitting on the charging dock after the battery reaches full charge. Continuous dock charging applies a low-level trickle current that accelerates cell degradation over weeks. Charge to full, then remove the unit from the dock.

Suction dropping before the battery indicator reaches low

The T30's motor controller pulls more current when airflow is restricted — a partially blocked filter forces the motor to work harder to maintain suction, which increases draw and causes voltage to sag earlier than the indicator expects. The battery indicator reads cell voltage, not current demand, so it can still show two bars while suction is already noticeably weak. This is not a battery fault — it is a load-side issue. Clean or replace the filter first, then retest suction performance.

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

This is a BMS overcurrent trip, not a motor fault. When suction is sustained against a blockage or a dense carpet pile, current draw spikes above the BMS threshold and the protection circuit opens the output to prevent cell damage. After a short pause the BMS resets and the motor restarts. Clear any blockage, check that the filter is clean, and avoid running the vacuum at maximum power setting on heavily restricted airflow. If the cutout repeats on an unblocked machine, check that the battery contacts are fully seated — a loose connection can cause momentary resistance spikes that read as overcurrent to the BMS.