BatteryRank scoring formula, in the open.
Every number on BatteryRank is derived from sourced data and documented assumptions. This page shows exactly what goes into a score, where the data comes from, and what we deliberately don’t model — because honest limits build more trust than false precision.
Scoring catalog v1.3 · updated Jul 6, 2026
Three buyer questions, three engines.
Which one should I buy?
The BatteryRank Score and use-case rankings — a composite of seven sourced sub-scores, re-weighted per use case (camping, CPAP, home backup, van life…).
What size do I need?
Device-first runtime math. Pick your CPAP, fridge, or phones and we return honest hours — real conversion losses already subtracted, not the label.
Is that spec real?
Every figure carries a source URL and a date. A manufacturer claim and an independently verified measurement are drawn differently and never blended.
Seven sub-scores behind one number.
The headline 0–100 score blends seven single-facet sub-scores, each a normalized function of sourced specs. They’re combined by a versioned weighting we tune deliberately — no single factor is allowed to dominate.
- Capacity & expandabilityusable watt-hours and how far the pack can grow
- Output power & versatilitycontinuous and surge watts, plus the port mix
- Trust & reliabilityratings weighted by review volume, and documented recalls
- Charging speed & solarhow fast it refills from the wall and the sun
- Durability & longevitycell chemistry, rated cycles, and warranty
- Portabilityreal weight and bulk, judged against its size class
- Quiet / off-grid livabilitynoise under load and off-grid niceties
The score renormalizes over whatever data a model has — so a model is never penalized for a spec nobody in its class publishes.
The score is price-independent. There is no “value” axis in the composite, and there never will be. Price moves daily; a station’s quality doesn’t — so the score you read today means the same thing next week, and a discount can never buy a better rank.
Four pillars on every model page.
The seven sub-scores collapse into four readable pillars for the radar on each model page — the same math, grouped the way a buyer thinks.
Power
Capacity + output power
Trust
Reliability + durability
Charging
Charge speed + solar
Livability
Portability + quiet running
The conventions behind every number.
Peer groups, not one big pile
Relative scores are computed inside six size cohorts (from ≤350 Wh carry units to >4,200 Wh whole-home). A 128 Wh power bank is never ranked against a 12 kWh home unit.
Two honest normalizations
Class-relative facts use a percentile within the cohort; facts with an absolute “good” (noise, warranty years, star rating) use fixed, documented thresholds.
Missing data renormalizes — never zero
A blank spec is dropped from its sub-score’s weight pool, not scored as zero. Lose more than half the inputs and the sub-score shows N/A rather than a misleading number.
Claimed vs. verified, always distinct
Manufacturer figures wear a dashed outline; independently confirmed ones earn a solid pine shield. Estimates are tagged “est.” and shown as ranges, never point figures.
Where every number comes from.
No press releases, no sponsored data, no brand partnerships. Each figure traces to one of these, carries its source, and is dated.
OEM spec sheets & manuals
claimedClaimed specs — capacity, rated output, cycle life, ports, warranty — read from the manufacturer's own datasheet or manual, one field per concept across brands.
FCC / UL / DOE & lab results
verifiedWhere an independent result confirms a claim — certifications, teardown or lab measurements — the figure is promoted to verified and wears a pine shield.
Independent teardowns & measurements
verifiedWhere a reviewer or lab publishes a measured figure — real outlet energy, inverter efficiency, noise — we record it against its source and mark it verified rather than claimed.
Ratings & documented reputation
trustSourced, countable reputation facts — documented recalls, complaint volume, warranty terms, and independent outlet ratings. Never coded from vibes or unsourced sentiment.
What we deliberately don’t do.
- No editorial listicles — every ranking is computed from the published formula, and nobody pays to sit at the top.
- No invented review sentiment. Every rating shown is credited to the outlet or marketplace that published it.
- No fabricated numbers. If a spec can't be traced to an authoritative source, it stays claimed, marked N/A, or is hidden — never guessed.
- No number without a source and a date. Prices always carry an “as of.”
Scoring catalog v1.3 · last updated Jul 6, 2026. Think a number is wrong? We want to know — with a source.
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