How long can the Bluetti AC300 + B300K run a Space heater?
3.1 hours
Formula: (2.8kWh × 0.85 inverter efficiency) ÷ 18 kWh/day = 3.1 hours. At continuous 1500 W draw (no duty cycle), about 1.6 hours.
What if you add a battery? The AC300 + 2× B300K config jumps to 5.5kWh — roughly 6.3 hours on a Space heater.
Appliance
Space heater · 1500 W / 1500 W surge
Battery (base)
2.8kWh · 3kW / 6kW 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.
3.1 hours
Formula: (2765 Wh × 0.85) ÷ 18 kWh/day = 3.1 hours. Continuous draw ≈ 1.6 hours at full load.
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