About this replacement
SUPRO EVS-C11 MAX / EVS-C11 MAX-DC — 22.2V Li-ion Replacement Battery (A11)
This is a 22.2V 2200mAh Li-ion replacement battery for the SUPRO EVS-C11 MAX and EVS-C11 MAX-DC cordless stick vacuums. It slots in where the original A11 pack sits and restores full motor voltage to the cleaning head. Capacity is 2200mAh (48.84Wh), matching the factory specification.
- EVS-C11 MAX and MAX-DC compatibility: Both variants run the same 22.2V six-cell architecture and share the A11 connector and BMS handshake profile. One battery covers both models without modification.
- Bench tested on actual hardware: We cycled this pack through motor-start loads on the EVS-C11 MAX. The BMS handled the inrush current at startup without tripping, and cell voltage held steady across sustained suction draws on the cleaning head.
- Dock charging habit on cordless vacuums: Do not leave the EVS-C11 MAX sitting on its charging dock continuously. Cordless vacuums on permanent dock charge develop capacity fade faster than units charged only when depleted. Charge to full, then remove from the dock.
Suction dropping before the battery indicator reaches low
The EVS-C11 MAX motor draws significantly more current when the filter is partially blocked. Under that restricted load, cell voltage sags earlier than the indicator circuit expects, so the vacuum feels underpowered while the gauge still reads mid-range. This is not battery failure — it is the BMS reducing output to stay within safe discharge limits under a higher-than-rated draw. Clean or replace the filter first, then retest. If suction recovers immediately, the battery is fine.
Motor cutting out briefly then recovering during a cleaning pass
Short cutouts that self-recover within a few seconds point to a BMS overcurrent trip, not a failed cell. This happens when sustained suction against a blockage — packed carpet fibres, a clogged inlet — forces the motor to draw above the BMS current threshold. The BMS interrupts current, waits for the draw to drop, then resets automatically. Clear the blockage, check the filter, and confirm the pack voltage reads at least 21V on a multimeter before ruling out a degraded cell.