How long can the EcoFlow DELTA Pro 3 run a CPAP machine?
10.9 dayswell beyond what you asked for
Formula: (4.1kWh × 0.85 inverter efficiency) ÷ 0.32 kWh/day = 10.9 days. At continuous 40 W draw (no duty cycle), about 3.6 days.
What if you add a battery? The + Extra Battery config jumps to 8.2kWh — roughly 21.8 days on a CPAP machine.
Appliance
CPAP machine · 40 W / 60 W surge
Battery (base)
4.1kWh · 4kW / 8kW surge
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Runtime Quick-Check
Runtime Quick-Check
Pick a battery and an appliance — see days of runtime after the 0.85 inverter derate.
10.9 days
Formula: (4096 Wh × 0.85) ÷ 0.32 kWh/day = 10.9 days. Continuous draw ≈ 3.6 days at full load.
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