About Solar DIY Project

Solar DIY Project is an independent publication about planning small off-grid solar systems — sheds, RVs, vans, cabins, camera poles, gate openers, and portable backup power. We publish sizing guides, calculators that show their working, and reference tables that cite the standard or datasheet each number came from.

We exist because the beginner-facing solar internet is full of numbers with no provenance. Articles assert that you need "about 400 watts" without showing the arithmetic, forum posts quote ampacity figures without naming the table, and calculators return a result while hiding every assumption that produced it. None of that is checkable, which means none of it is trustworthy, which matters more than usual when the subject is wiring that can start a fire.

Who writes this

The site is written and maintained by a small editorial team and published under the site's name rather than individual bylines. We think you deserve to know that plainly rather than discover it, so: we are not licensed electricians, we are not engineers, and we are not presenting ourselves as either. We are writers who research carefully and show our sources.

That is a real limitation, and we have built the site around compensating for it. Rather than asking you to trust a byline, every page is designed so you can check the work without trusting us at all:

• Formulas are printed, not hidden. Where a guide produces a number, the equation and the inputs are on the page so you can redo the arithmetic by hand.
• Reference values name their source and table number. If we say 8 AWG copper is rated 50 A, we say which table said so, under what assumptions, and link to it.
• Uncertainty is labelled. When we could not verify a figure against a primary source, we say so on the page rather than rounding it into a confident-sounding sentence. When two standards disagree, we publish both and explain why they differ instead of silently picking one.
• The boundary of our competence is marked. Grid interconnection, roof structural work, permit-bound installation, and high-current battery banks are explicitly flagged as professional territory. We do not pretend to cover them.

How a page gets made

Every guide and table follows the same route. We start from a decision a reader actually faces — how big a battery, what size wire, which fuse — rather than from a keyword. We gather the governing figures from published standards, manufacturer datasheets, and public datasets, recording the document and section for each one. Any lookup table we publish is transcribed from a cited source, and any derived table is generated from a stated formula rather than typed by hand, so the arithmetic is consistent across every row.

Worked examples are computed end to end and spot-checked against an independent calculation. Where a figure could not be traced to a primary document, it is either cut or published with an explicit caveat. Pages are then revisited when a referenced standard, datasheet, or dataset changes, and the update date on the page reflects the last substantive revision.

Our examples are illustrative, not field reports

This matters enough to state outright. The load tables, system layouts, and worked examples on this site are constructed to demonstrate a method. They are not write-ups of installations we personally built, and we do not present them as such. You will not find us claiming a component was "tested over two winters" or showing photographs of a build we did not do.

Where real-world performance data matters — irradiance, cycle life, temperature behaviour — we cite measurements published by people who actually took them, such as NREL datasets and manufacturer test data, rather than inventing our own.

How the site is funded

Solar DIY Project is supported by display advertising. Advertisements are served by a third-party network and are not selected, reviewed, or endorsed by us, and the presence of an advert has no bearing on editorial content.

We do not sell hardware, we do not accept payment for coverage or placement, and no manufacturer has editorial input. Where we name a specific product it is because it illustrates a point, not because anyone paid for the mention. If that ever changes — if we add affiliate links or accept sponsorship — it will be disclosed on the affected pages before it appears, not buried here.

What this site is not

• It is not a substitute for your local electrical code or for a permit.
• It is not a substitute for the installation manual that came with your equipment. Where our guidance and a manufacturer's manual disagree, follow the manual.
• It does not cover grid-tied or grid-interactive systems, utility interconnection, or anything requiring an electrician's sign-off.
• It does not certify installations or provide engineering review.

Corrections

We would rather be corrected than be wrong quietly. If you find an error — a mistranscribed table value, a formula applied incorrectly, a standard we cited from a superseded edition, a claim we did not support — send it to us with the page URL and the source you checked against.

Substantive corrections are made to the page and the update date is revised, so a reader can see the page changed. We do not silently edit a figure and leave the original date in place. If a page turns out to be wrong in a way that cannot be patched, we retract it rather than quietly deleting it.

Our full review approach is on the editorial policy page.

Safety

Low-voltage does not mean low-risk. A 100 Ah lithium battery can deliver enough current into a dropped spanner to vaporise metal, and DC arcs do not self-extinguish the way AC arcs do. If a project involves roof work, utility connection, permanent building wiring, or a battery bank of any real size, involve a qualified professional. If something in your existing system is hot, smells, or has discoloured insulation, disconnect it and get it looked at rather than reading another article about it.