Methodology

Evidence before relationship

1. Record product and regional identity from an official source.
2. Store marketing and nominal voltage separately.
3. Record battery-to-tool and charger-to-battery direction.
4. Attach the source and verification date to each rule.
5. Publish pass, warning, fail or unknown. Unknown never passes.

Optimization after feasibility

The optimizer searches real bare tools and decomposed kits, reuses owned components, enforces compatibility, then ranks feasible baskets. Affiliate commission is not an input.

Synthetic offers are permitted only in automated tests where the mathematical optimum is known.

Editorial research standards

Etrenank Research publishes model-specific US-market guides from manufacturer pages, manuals and catalogs. Every guide identifies its official sources, publication date and last review date. English, Spanish and Japanese editions express the same conclusions; translations do not create new claims.

What our guides do not claim

Guides distinguish documented manufacturer facts from calculations and editorial comparisons. Unless a page explicitly says otherwise, Etrenank has not conducted hands-on runtime, durability or laboratory testing. Retail availability and prices can change and are not used as compatibility evidence.

Updates and corrections

We review a guide when its underlying catalog record, manufacturer documentation or conclusion changes. The visible last-reviewed date and sitemap date are updated together. Corrections are checked against the exact official source; unsupported claims are removed or marked unknown.