Methodology
How WattBench scores power stations.
Published weights, a consistent runtime formula, and a clear list of what we do not measure. The goal is a useful comparison, not a false precision.
The WattBench score
Every station is scored from 0 to 10 across six dimensions, then weighted. Each dimension is normalized against the full product database, so a score reflects the current market rather than an arbitrary rubric.
| Dimension | Weight | What it captures | Direction |
|---|---|---|---|
| Capacity | 25% | Rated watt-hours | Higher is better |
| Output | 20% | Continuous inverter watts | Higher is better |
| Portability | 15% | Weight in pounds | Lower is better |
| Recharge | 15% | Published AC recharge time | Lower is better |
| Expandability | 10% | Maximum expansion capacity | Higher is better |
| Value | 15% | Street price per usable watt-hour | Lower is better |
Normalization uses min-max scaling across the database. Expandability uses a log scale so that 10kWh and 50kWh are treated as different tiers rather than a 5x linear gap. A station with no expansion scores at the bottom of that dimension, not zero on the overall score.
The 85% usable-energy rule
Runtime estimates use 85% of rated capacity: usable Wh = rated Wh x 0.85. That factor accounts for inverter losses, battery-management overhead, and a healthy depth of discharge. It is conservative by design.
Runtime in hours = usable Wh / average load in watts. For a multi-appliance plan, add the average wattages together. For a fridge, use its average draw, not its compressor's running wattage.
What we do not measure
- We do not run lab discharge tests or measure inverter efficiency curves.
- We do not claim hands-on testing, drop tests, or sound-level measurements.
- We do not use owner surveys or invent quotes.
- We do not treat manufacturer peak-power marketing as continuous output.
- We do not model startup surge in runtime estimates; check it separately.
Data sources
Specifications come from manufacturer product pages, spec sheets, manuals, and retailer listings, checked in November 2026. When a manufacturer does not publish a figure, we say so rather than filling the gap with an estimate. Price bands come from observed street prices and are labeled as bands, not live quotes.
Affiliate independence
Commission rates and cookie windows vary by merchant, but they do not affect scores, rankings, or verdicts. The scoring model is fixed before we write a page. If a merchant changes a program, that does not trigger a ranking change.
Updates and corrections
Pages show a checked date. We update specs and price bands as products change. To report an error, email wildbills1977+wattbench@gmail.com with the product, field, and source.
See it applied
Read a comparison with the math shown.
The 2kWh value matchup is a good example: same capacity, different output, expansion, and price per usable watt-hour.