Precise. Calm. Honest about uncertainty.

Why BatteryCaliber exists

Off-grid homeowners, campervan and RV builders, boat owners and solar DIY researchers often start with the same questions: how much battery do I need for a few days without charging, how much current will my inverter draw, and how much voltage will my cables lose? BatteryCaliber answers those questions as transparent planning estimates, so you can arrive at a qualified installer’s review better prepared.

What we do—and don’t do

• We publish every equation, default and boundary on the Methodology page.
• We keep continuous and surge current separate, use your actual nominal and minimum voltages, and round capacity upward.
• We do not size conductors or fuses, certify compliance, guarantee equipment compatibility or replace an electrician.
• We do not collect your calculator inputs. Calculations run in your browser.

Editorial standards

• Evidence first. Technical statements are linked to primary sources where possible, with their limits noted. A source being cited does not mean it sponsors or approves this site.
• No invented credentials. We don’t list fictional engineers, testimonials, awards, certifications or partner logos.
• Honest products. Hardware is never described as tested, certified, compatible or approved without retained evidence for that exact claim. Hardware links currently point to Amazon category searches, not endorsed products; see the Affiliate Disclosure.
• Versioned corrections. Formula changes are tested, versioned and logged. Corrections are made promptly rather than on a publishing calendar.
• Review status. Calculator v1.0.0 has passed automated arithmetic and input tests. Independent electrical review is pending, and we say so.

Who runs the site

BatteryCaliber is an independent website based in the United States. It is not affiliated with, sponsored by or endorsed by any battery, inverter or cable manufacturer, or by NFPA or ABYC.

Report an error

If you think a result, formula or statement is wrong, email contact@batterycaliber.com with your inputs, the result you saw and what you expected. Safety-related reports are prioritised. We cannot provide installation-specific design advice by email.