About Off Grid Authority

§1 What this site is

Off Grid Authority is the free, independent reference manual for DIY off-grid power. If you are designing a solar system for a cabin, a van, a tiny home, a shed, or a boat — and you want to understand the numbers rather than be sold a kit — this is built for you.

It is two things working together: a library of plain-language guides covering panels, batteries, charge controllers, inverters, wiring, mounting, and the legal landscape; and a set of five calculators that turn your loads and conditions into real specifications. The reference is independent and solo-published. Every page is free, with no paywall and no gated "premium" tier.

• System Calculator — panel, battery, and inverter sizing from your loads.
• Wire Size Calculator — conductor gauge from ampacity and voltage drop.
• Battery Bank Calculator — usable capacity, series/parallel layout.
• Load / Appliance Calculator — daily watt-hours from your appliance list.
• Array Layout Tool — string and array configuration.

§2 How we research

Specifications are compiled and cross-checked against manufacturer datasheets and against the relevant code requirements from the National Electrical Code (NEC) and, for marine builds, the American Boat and Yacht Council (ABYC) standards. When a guide states a figure — a panel's open-circuit voltage, a battery's usable depth of discharge, an inverter's surge rating — it traces back to a published source, not to a guess.

The calculators are not toys that multiply two numbers. They implement the actual code tables. The wire tool, for example, sizes conductors using the NEC 310.16 ampacity table and computes voltage drop with the conductor resistance values from NEC Chapter 9, Table 9 — the same references an electrician would open.

Every page carries a "Last verified" date. That stamp is a promise: the page was checked against current sources on that date, and it gets maintained, not abandoned. When code or product reality changes, we revisit and re-date the page rather than leaving stale numbers up.

§3 What we don't do

The fastest way to understand a reference site is to know what it refuses to do:

• No sponsored placements. No brand pays to appear in a guide, a comparison, or a recommendation.
• No pay-to-rank product picks. Ranking position is never for sale. A product is mentioned because its published specs and code fit earn it a place.
• No invented credibility. No fake founder bios, no stock photos of a "team," no imaginary testing lab. This is an honest, independent reference, and it says so.

We do use affiliate links to help keep the site free. Those links are disclosed in full on our affiliate disclosure page, and they never determine what we recommend. The recommendation comes first; the link is added afterward, only where it points to the product the spec already chose.

§4 How to use the manual

New to off-grid power? Begin with Start Here: the off-grid living beginner's guide walks through the whole picture before you spend a dollar.

Once you know roughly what you need, move to the Tools to get real numbers for your build, then dip into the reference buckets — Fundamentals, Sizing & Design, Build Guides, Systems, and Land & Legal — to go deep on any one component. The navigation at the top of every page groups everything into those buckets so you can jump straight to the part you need.

A good path for most people: read the beginner's guide → run the load calculator to find your daily watt-hours → feed that into the system calculator → confirm your wiring with the wire size calculator.

§5 Corrections policy

This manual is only as good as its accuracy, and no reference is perfect. If you find an error — a spec that looks off, a calculation that does not match your build, or a code reference that has changed — tell us through the contact page. We cross-check the figure against the relevant datasheet or code requirement, fix what needs fixing, and bump the page's verified date so you know it was reviewed.

That feedback loop is the whole point. A maintained reference beats a polished one that nobody updates.