How long can the Tesla Powerwall 3 run a Router + modem?
23.9 dayswell beyond what you asked for
Formula: (13.5kWh × 0.85 inverter efficiency) ÷ 0.48 kWh/day = 23.9 days. At continuous 20 W draw (no duty cycle), about 23.9 days.
Appliance
Router + modem · 20 W / 20 W surge
Battery (base)
13.5kWh · 11.5kW / 11.5kW surge
Runtime Quick-Check
Runtime Quick-Check
Pick a battery and an appliance — see days of runtime after the 0.85 inverter derate.
23.9 days
Formula: (13500 Wh × 0.85) ÷ 0.48 kWh/day = 23.9 days. Continuous draw ≈ 23.9 days at full load.
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