How we pick
The criteria, the sources, and a plain list of what this site does not do. Read this first if you want to know how much to trust the rest.
This is the most important page on the site. It is the honest substitute for a test lab, and it is what you should read if you want to know how much weight to put on anything else here.
What this site does not do
Starting here, because it is the part most review sites leave out:
- We do not run instrumented lab tests. There is no test rig, no dynamometer, no thermal chamber and no fleet of test vehicles. We do not publish measured cranking currents, fill times, gauge deviations or temperature curves, because we did not measure them.
- We do not publish prices. We have no live price feed, and a stale price is worse than no price. Every buy link goes to the retailer, where the current price is shown. There are no ranges, no "from $X", and no "was/now" figures anywhere on this site.
- We do not publish star ratings or aggregate review scores. Not ours, and not scraped from a retailer.
- We do not publish a numeric score for products. Our comparison tables carry a short qualitative verdict instead, because a precise-looking number like 8.4/10 implies a measurement we did not take.
- We do not accept payment for placement, or for a favorable verdict. No sponsored posts, no paid guest posts, no link sales.
- We do not claim first-hand use of products we have not used. No "we tested", no "in our testing", no "after three months with it".
What we do instead
We read specifications off the manufacturer's own published page, link that page on the article, and reason from those figures against a stated set of criteria. Where a manufacturer does not publish a figure, the article says so rather than filling the gap.
That is a narrower claim than most sites in this category make, and it is one we can substantiate on every page. You can click through to the source of any number here and check it yourself, which is the point.
The selection criteria
These are the criteria, in the order we weight them. They are drawn from the decision set of the reader this site is built for — the person who needs the tool to work away from home.
| Criterion | Why it decides things |
|---|---|
| Published engine rating (liters, by fuel type) | The only figure a manufacturer will stand behind under warranty. It already folds in the arithmetic that peak amps leaves to you. |
| Watt-hours | Determines how many starting attempts you get, and whether the pack can legally fly. This is the travel reader's binding constraint. |
| Weight and packed size | The tool that is genuinely small is the tool still in the vehicle a year later. Presence beats power. |
| Protection and build | Reverse-polarity protection, an IP rating, clamp and cable quality. |
| Charging input | A pack that charges from a cable you already carry is a pack that stays charged. |
| Warranty | What the manufacturer will actually back. |
| Criterion | Why it decides things |
|---|---|
| Duty cycle and throughput | The spec that predicts whether a unit can handle your tires. Frequently unpublished, in which case we say so. |
| Power source | Which failure mode you are accepting: a flat internal battery, or a dead car. |
| Chuck type | A threaded chuck seals; a clamp-on chuck hisses and loses you the air you are adding. |
| Preset with auto-shutoff | Turns a chore into a two-minute job, and stops overshoot. |
| Gauge behavior | Whether it measures with the pump stopped, and whether there is a usable display. We do not publish accuracy figures. |
| Criterion | Why it decides things |
|---|---|
| Current and published capacity range | Both are needed — current sets the speed, the amp-hour range sets what the unit is designed for. |
| Chemistry support | Flooded, AGM, EFB and gel want different charge voltages. An AGM on a flooded profile never reaches full. |
| A genuine float stage | Whether the unit can safely stay connected for months, which is the whole point of a maintainer. |
| Published cold rating | Most of this work happens in an unheated garage in winter. |
| Cable length | Whether it reaches from a wall outlet to the engine bay without an extension. |
| Warranty | The spread in this category is unusually wide, from one year to ten. |
Sources, in order of preference
| Tier | Source | Used for |
|---|---|---|
| 1 | Regulators — FAA, TSA, DOT, NHTSA | Lithium-battery travel rules, watt-hour thresholds, tire safety guidance |
| 1 | The manufacturer's own specification page for the exact model | Peak amps, watt-hours, engine ratings, PSI, capacity ranges, weight, IP rating, operating temperature, warranty |
| 2 | The live retailer listing | Current availability and configuration — never for price, because we publish none |
| 2 | Vehicle documentation — owner's manual, door-jamb placard | Recommended tire pressure, battery specification, designated jump points |
| 3 | Standards bodies — SAE, BCI | Definitions such as cold cranking amps, and battery group sizes |
| Not acceptable alone | Forums, Reddit, other affiliate sites, AI output, general blogs | May be noted as "commonly reported" with that framing. Never presented as fact, and never as the source of a specification. |
Two practical rules follow from that table. Regulatory claims are date-stamped, because rules change — where we state a watt-hour threshold we say when we read it and link the page. And we never cite a competing affiliate site as the source of a spec. If a figure is worth publishing, it is worth getting from the manufacturer.
Scope of assessment
Every roundup and review carries a plain statement near the top of what our assessment actually was. There are three honest forms and we use whichever is true:
- Researched, not personally used — "picks here are selected from manufacturer specifications, current retailer listings and published owner feedback, not from hands-on testing of every unit." This covers most pages.
- Genuinely owned and used — stated only where it is literally true of that specific unit.
- Mixed within one roundup — marked per pick, so you can tell which is which.
What we can speak to first-hand is the problem, not forty specific products: what actually happens when a battery dies away from home, why packed size decides whether a tool is still in the trunk in six months, why a combo unit's compressor is the compromise. That is experience about the use case, and we frame it that way.
How a pick loses its place
- Discontinuation. A product that is no longer sold is removed, not left in place with a dead link.
- A persistent stock problem. A recommendation you cannot buy is not a recommendation.
- A better product. Rankings change when something genuinely better ships.
- A specification change. Manufacturers revise models. If a published figure changes, the page changes.
- A pattern of failures in published owner feedback. Treated as a signal to re-examine, and described as what it is rather than as a test result.
Update cadence
Commercial pages — roundups, comparisons and model reviews — are reviewed on a rolling basis for discontinued products, changed specifications and better alternatives. Pages that cite regulations are re-checked against the regulator's page, because those are the claims where being out of date matters most. Every page shows its last-updated date, and that date reflects a real review rather than a build timestamp.
Corrections
Email contact@clampandcrank.com or use the contact form. If you can point at a manufacturer page that contradicts something here, that is the most useful message we can receive. Corrections are made and the page's updated date changes to reflect it.