BackupPower

Portable Power Station Runtime & Sizing Logic

This document outlines a simple, practical approach to estimating real-world runtime for portable power stations and small battery backup systems.

Advertised watt-hours (Wh) represent stored battery energy, not usable output. In real-world conditions, usable energy is reduced by inverter efficiency, DC-to-AC conversion losses, internal electronics, and system overhead. As a rule of thumb, usable capacity is typically 70–80% of the nominal rating.

Basic calculation model

1. List all devices to be powered
2. Estimate average power draw (not peak or surge ratings)