Direct answer
Maximum mode legitimately shortens runtime, but immediate shutdown can indicate a weak battery, blocked airflow, cold/hot battery or a high-resistance motorized tool.
What this covers
- Vacuums · battery
- The exact symptom in the title before component-level repair
- Consumer-accessible controls, connections and maintenance areas
What it does not cover
- ×Smoke, burning odor, swelling, liquid on powered parts or damaged wiring
- ×Opening sealed panels, bypassing interlocks or live-electrical testing
- ×Account ownership, billing or warranty disputes
Observe before changing anything
ReversibleCompare runtime on normal and maximum modes with and without the powered head.
Isolate the failing boundary
ReversibleClear airflow, cool the battery to room temperature and charge with the specified charger.
Apply the narrow correction
ReversibleRun a timed normal-mode test against the model’s expected conditions.
Verify the result and stop at the boundary
ReversibleReplace/service a swollen, overheated or drastically degraded battery; do not open the pack.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check first for “Cordless vacuum battery dies quickly on maximum power”?+
Compare runtime on normal and maximum modes with and without the powered head.
How do I know whether the problem is external or inside the device?+
Clear airflow, cool the battery to room temperature and charge with the specified charger.
When should I stop and request repair?+
Replace/service a swollen, overheated or drastically degraded battery; do not open the pack.
Answer for the exact device and software version shown above.