This page explains what happens before a product appears on Solar Powered Project — and what deliberately does not happen. It complements our methodology for calculations and our affiliate disclosure for how commissions work.
The short version
We recommend products the way a careful buyer would shortlist them: from manufacturer specifications, published standards, warranty terms, and the arithmetic of the job you’re trying to do. We do not run a test lab, we are not paid by brands, and we don’t display product prices on this site — the current price is always the one Amazon shows when you click.
How a product earns a mention
- The math has to point at it. Every buying context on this site starts as a sizing or runtime calculation (watts, watt-hours, voltage, surge, duty cycle). A product appears when its published specs fit the arithmetic of that scenario — a charge controller sized to the array voltage and current, a battery whose usable watt-hours match the runtime being planned.
- Specifications come from the manufacturer. Capacity, voltage windows, continuous and surge ratings, chemistry, protections (BMS features, low-temp charging cutoffs), warranty length. Where specs matter to safety, we prefer the manufacturer’s datasheet over a retailer listing.
- Track record over novelty. For categories with a long community history — MPPT controllers, LiFePO4 batteries, power stations — we favor models with an established multi-year presence and visible support, over unproven new listings.
- Value framing, not price promises. We compare products by durable characteristics (cost per usable watt-hour over cycle life, warranty years, feature set), never by today’s price — prices change too fast for anyone’s table to be trusted, which is also why you’ll never see us quote one.
What we do not do
- No fabricated testing. Unless an article specifically documents a real build with measurements (our Project Lab articles do), assume nothing here has been bench-tested by us. We will not claim otherwise.
- No brand payments or review units. Brands do not pay for placement, do not receive drafts, and do not approve anything. If that ever changes, this page changes first.
- No “best” without a basis. Where a page says “best for” a scenario, it means “best-matched by specs and math for that use case” — and the page shows the criteria so you can disagree with us.
- No price displays or price tracking. Program rules (and honesty) require it: prices and availability are whatever Amazon shows when you click through. Our product boxes link; they don’t quote.
Why we link to Amazon
Readers buy the components we discuss somewhere, and Amazon Associates commissions fund the site without paywalls. Links are marked as sponsored, disclosures sit next to them, and the commission never changes the math — a controller that loses the arithmetic on this site loses it whether we’d earn a commission or not. If a product that wins the math isn’t available on Amazon, it still gets named; no link.
When we change or remove a recommendation
Specs change, products get discontinued, warranties get rewritten, and better options appear. When that happens we update the guide and, where the change is material, note it on the corrections page. If you believe a recommendation on this site is wrong — a spec that’s drifted, a model with a failure pattern we’ve missed — tell us; that feedback genuinely shapes revisions.