Every battery tester gets a score from 0 to 100% built from five factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Testers are grouped into digital testers, digital testers with a built-in printer, and load testers, and use the same scale in every group.
| Factor | Measures | Weight |
|---|---|---|
| Price | current price | 25% |
| Battery coverage | highest CCA rating tested, plus 6 V batteries and 24 V systems | 25% |
| System tests | starter, charging system and ripple tests | 20% |
| Features or load | printer, screen, lithium, app report, memory, own battery and cable length; load current for load testers | 20% |
| Warranty | warranty length | 10% |
Where the numbers come from
Rating ranges, voltages, battery types, standards, tests, features and warranty come from the maker’s manual or product copy, including the maker’s own copy on a retail listing. Where a maker’s own figures conflict (for example a title that gives one CCA range and a bullet that gives another), the conflicting figure is left out rather than guessed. Prices are checked at the stores each page links to, and the lowest is used.
The factors
Price is the current price on a log scale, so halving the price always counts the same. $500 scores zero and $50 full marks.
Battery coverage is 60% for the highest battery rating the tester reads, 20% for testing 6 V batteries and 20% for covering 24 V systems (a 24 V battery or a 24 V starter and charging test). For the rating, 600 CCA scores zero and 2,000 CCA full marks. A rating given only in cranking amps (CA) rather than CCA isn’t converted.
System tests is 40% for a starter (cranking) test, 40% for a charging system test and 20% for an alternator ripple or diode check.
Features or load depends on the type. For digital testers it is 25% for a built-in printer, 15% for a color screen or a phone app display, 15% for testing lithium batteries, 15% for a phone app or QR-code report, 10% for storing past results, 10% for having its own battery (so it works on a nearly flat one) and 10% for a test cable of 5 ft or more, long enough to run the starter test from the driver’s seat. For load testers it is the load current on a log scale: 100 A scores zero and 1,000 A full marks.
Warranty is the maker’s warranty: 1 year scores zero and 3 years full marks.
What isn’t scored
The low end of the rating range, battery types beyond lithium, the list of rating standards, screen size and release date are listed but not scored. Accuracy claims aren’t scored either, since makers state them in ways that can’t be compared.
Missing data
The highest battery rating is the figure that most separates testers, so when a maker doesn’t publish it, that part of battery coverage scores zero (the bottom of the scale) and the product page marks it as estimated. If no system tests are published, or no features (or no load current) are published, that factor gets the neutral middle score (50) and is marked as estimated; a test or feature the maker doesn’t mention otherwise counts as absent. A maker that doesn’t publish a warranty gets no warranty counted, so that factor scores zero, the same as a one-year warranty, and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.