About this replacement
ETA 4237 Stormio — 14.4V Li-ion Replacement Battery (INR18650/33V-4S1P-AAF)
This is a 14.4V, 3200mAh Li-ion battery pack for the ETA 4237 Stormio cordless stick vacuum. It replaces the original pack when capacity has degraded or the battery no longer holds a charge. Voltage and cell count match the original 4S1P configuration the Stormio motor controller expects.
- ETA 4237 Stormio fit: The Stormio motor runs on a 14.4V nominal rail with a 4-cell series pack. This replacement uses the same 4S1P cell layout and BMS communication the vacuum's charge circuit expects, so the indicator LEDs and cutoff thresholds behave as they did with the factory pack.
- Bench tested on actual hardware: We cycled this pack under sustained motor load and confirmed the BMS holds the overcurrent trip point correctly. The protection circuit disengages cleanly at low-cell voltage and resets without requiring a manual re-trigger.
- Dock charging on the Stormio: Do not leave the Stormio sitting on its charging dock permanently. Continuous trickle current from the dock accelerates capacity fade in Li-ion packs faster than normal cycle wear. Charge to full, then remove the vacuum from the dock until the next use.
Cordless vacuum losing suction before the battery indicator reaches low
The Stormio motor draws more current when airflow is restricted — a partially blocked filter or clogged bin forces the motor to work harder to maintain suction. That increased draw causes the cell voltage to sag under load even though the pack's resting charge looks healthy. The BMS reads the sag as a near-depleted state and throttles output before the indicator visually registers low. Clean the filter first; if suction recovers and holds, the battery is fine — the root cause was current draw, not capacity.
Motor cuts out mid-clean and then recovers after a few seconds
This is a BMS overcurrent trip, not a failing battery. When the vacuum ingests a blockage or runs over heavy debris with a restricted filter, instantaneous current spikes past the protection circuit's trip threshold. The BMS disconnects the output rail to protect the cells, then resets automatically once current demand drops — which is why the motor comes back after a short pause. Check the filter and clear any blockage in the suction path; if the cutout stops happening, the pack is operating correctly. If cutouts continue on a clean filter at 14.4V resting voltage, the BMS trip threshold may have shifted and the pack should be replaced.