Signs of a Bad Car Battery and How to Confirm Each One
The signs of a bad car battery, what each one really means, and the quick voltage checks that separate a bad battery from a bad alternator or starter.
Battery Testing
Car battery testing guides for US drivers and home mechanics. We show you how to check a 12V battery with a multimeter, what every voltage reading means for flooded, AGM and lithium batteries, and when a dedicated battery tester tells you more than a voltmeter can. Every number comes from a battery or tester maker’s manual, with conflicts between sources shown side by side, and every tester pick is checked against years of Amazon sales, price and review history. Start with our multimeter guide, read the car battery voltage chart, then compare our picks for the best car battery tester.
Best Car Battery Tester: 4 Picks That Passed Our Checks
The best car battery tester for most drivers is a 12V digital model, and these four picks passed our manual, sales-history and price checks for different jobs.
Car Battery Voltage Chart: What Each Reading Means
This car battery voltage chart shows what each reading means with the engine off, while cranking and while running, and how AGM and lithium batteries read differently.
How to Test a Car Battery with a Multimeter
Learn how to test a car battery with a multimeter in five steps, what each reading means, and how three quick readings point to the battery, starter or alternator.