EV & High-Draw · CEC Section 64 (Energy Storage Systems)

Battery Backup Runtime Calculator

Estimate how many hours or days your home battery system (e.g. Tesla Powerwall, Enphase, EcoFlow) will power essential loads during a outage.

Battery Storage Capacity (Usable kWh)

Depth of Discharge Reserve (% DoD)

Average Connected Load Draw (Watts)

ESS CEC Section 64

ESTIMATED BACKUP RUNTIME

18.7 Hours

USABLE ENERGY DELIVERED

12.15 kWh

DAYS OF CRITICAL BACKUP

0.8 Days

Essential Load Match: Powering fridge, lights, router, and sump pump smoothly during a typical blackout.

Inverter conversion efficiency averages 88%–92% (DC battery power converted to 120V AC household electricity).
High surge loads like HVAC compressors or well pumps can cause rapid energy drain or trigger inverter surge trip limits.
CEC Section 64 requires Energy Storage Systems (ESS) over 20kWh to follow specific garage / exterior firewall rating rules in residential dwellings.