About & methodology

Backup Runtime is an independent site with free calculators for EV home backup and outage planning. It is not affiliated with any automaker, battery maker or installer.

Where the numbers come from

Every data point carries one of four labels, shown next to it on each tool page:

• Official: published by the manufacturer, with a link to the page.
• Third-party: from an independent spec database or publication, with a link.
• Estimate: a typical value or site assumption, explained in the notes.
• Derived: calculated from other values on the page.

Third-party figures are never presented as official. When the manufacturer only says that “some, but not all” vehicles qualify, the tools say the answer needs to be verified in the vehicle.

How calculations work

All results come from plain, deterministic arithmetic that runs in your browser and is covered by automated tests. Each tool page shows its formula and assumptions. Your inputs are never uploaded.

Corrections

Specs and eligibility rules change. Each page shows when its data was last verified, and changes are listed in the page's changelog.

Not professional advice

The tools are planning estimates, not electrical engineering. Have a licensed electrician or certified installer design and verify any home backup system.