We recommend from documented needs and evidence. There is no universal winner and we do not perform physical product tests.
1. Match the exact product
Base stations, expansion batteries and bundles remain separate. Regional voltage, sockets and seller terms need their own evidence. A model-family name or a price in euros does not establish delivery across Europe.
2. Show what each source establishes
Specifications link to their sources and check dates. A manufacturer statement, retailer listing, external measurement and editorial calculation are different evidence types, not interchangeable quality scores. Missing information stays unknown; conflicting claims remain visible.
3. Explain the decision
Each record identifies a reason to consider the model, a trade-off and a purchase check. A recommendation depends on the job: load, energy budget, handling, charging and regional buying route. A missing critical fact prevents a confirmed match, rather than making the product automatically bad.
4. Make ordering understandable
The Index defaults to search match, then brand and model order. You can sort by a chosen numeric field. Unknown or conflicting values sort last and do not pass a numeric limit. Dated base-unit prices stay in their original currencies. No commission controls these results.
5. Keep calculations and measurements separate
Nominal Wh is not usable AC energy. The energy planner shows user-selected assumptions and candidates for checking, not guaranteed runtime. External results identify the tester, configuration and known method. We do not fill missing measurements with class averages or derive lifetime ownership cost from a cycle count.
6. Maintain the record
Source check dates describe evidence checks; article update dates describe material editorial changes. Prices are snapshots, not live quotes. We prioritise corrections and facts that affect a recommendation. We do not claim a universal automatic refresh schedule.
Research standard version 1.0, updated 14 September 2026. Corrections and changes · External measurements · Commercial policy.