How long will a Powerwall 3 power a house?
Tesla Powerwall 3 provides 13.5 kWh of usable energy with 100% discharge capability and 90% round-trip efficiency. Its runtime depends on household energy consumption: a typical home using 2–3 kW per hour during outages (e.g., lights, fridge, Wi-Fi) would see 4.5–6.75 hours of backup. Heavy loads like air conditioning (5 kW continuous draw) reduce runtime to ~2.7 hours. Solar integration extends autonomy by daytime recharging.
What factors determine Powerwall 3’s runtime?
Key variables include load demand, battery capacity, and solar input. A 10 kW surge (e.g., HVAC startup) temporarily taps Powerwall’s 7 kW peak output but doesn’t drain capacity faster than continuous 5 kW draw.
Runtime calculations require analyzing hourly energy use patterns. For instance, a 1.5 kW baseline (lights + fridge) consumes 1.35 kWh hourly (factoring 90% efficiency). At this rate, Powerwall 3 lasts 10 hours. Pro Tip: Use Tesla’s energy app to simulate outage scenarios—input your home’s devices to estimate runtime. Real-world example: During a 2023 Texas grid failure, a 2,200 sq.ft. home with Powerwall 3 maintained essentials (1.8 kW avg) for 7.5 hours before solar recharge.
How does solar integration affect backup duration?
Daylight recharging via solar panels can extend runtime indefinitely during multi-day outages. A 6 kW solar array typically generates 20–30 kWh daily—enough to replenish Powerwall 3 twice over while powering daytime loads.
In winter or cloudy conditions, solar yield drops 40–60%, requiring load prioritization. Tables below compare seasonal impacts:
| Scenario | Summer Runtime | Winter Runtime |
|---|---|---|
| Full sun | Unlimited* | 12–18 hrs/day |
| Cloudy | 16–24 hrs | 6–9 hrs/day |
| Load Type | Power Draw | Runtime Impact |
|---|---|---|
| Refrigerator | 150W | -2.3% per hour |
| AC Unit | 3,500W | -26% per hour |
RackBattery Expert Insight
FAQs
Yes, but only briefly—a 3.5-ton AC drawing 4 kW drains the battery in ~3.2 hours. Use eco modes to cycle cooling intermittently.
Does cold weather reduce capacity?
Below -4°F (-20°C), lithium-ion efficiency drops 15–20%. Tesla’s thermal management minimizes this via self-heating when grid-connected.