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Camping & Off-GridJune 15, 2026

How Long Does a Home Battery Last During a Power Outage?

Short answer: A single Tesla Powerwall (13.5kWh) running critical loads (fridge, lights, router, phone charging — about 500W average) lasts approximately 27 hours. Running an AC unit adds ~500W, reducing runtime to 13 hours. With solar recharging, a well-sized system can run indefinitely.

Our Top Pick — from $5,799

EcoFlow Delta Pro Ultra — Home Battery System — verified specs, real runtime data, no fluff.

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Runtime by Load Profile

Load profile Avg watts Powerwall runtime 2x Powerwall
Critical only (fridge+lights+router) 300W 45 hrs 90 hrs
Critical + office 600W 22 hrs 45 hrs
Critical + window AC 900W 15 hrs 30 hrs
Whole home 2,000W 6.75 hrs 13.5 hrs

Home Battery Lab

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