Battery & Charging System Tester: Buying guide
What it is
A battery tester measures your battery's state of charge and health (often via cold-cranking-amps), and the better ones also test the alternator's charging output and the starter's draw.
Why you need it
A weak battery or charging fault causes no-starts, random electrical gremlins, and low-voltage codes like P0562. A tester tells you in seconds whether the battery, the alternator or the starter is the problem — so you do not replace a good battery.
Features to look for
- Tests battery health (CCA), not just voltage
- Charging-system (alternator) and starter-draw tests
- Supports your battery type (flooded, AGM, EFB)
- Clear pass/replace/charge readout
- Reverse-polarity protection
How to choose
- A simple plug-in tester is fine for checking state of charge; for diagnosing no-starts get one that reads CCA and tests charging.
- Make sure it supports AGM batteries if your car has stop-start.
- Conductance testers give a quick health verdict without a full load test.
- Pair the result with a multimeter: ~12.6 V rested battery, ~13.5–14.5 V charging at the battery.
Where to buy
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Helps diagnose these codes
Related parts
Frequently asked questions
Is it the battery or the alternator?
A battery & charging tester answers exactly that: it reports the battery's health (CCA) and whether the alternator is charging correctly (about 13.5–14.5 V). A P0562 low-voltage code plus a failed charging test points to the alternator.
Do I need a special tester for an AGM battery?
You need one that supports AGM. Many testers have a battery-type selector; choosing the wrong type can give an inaccurate health reading, which matters on stop-start cars with AGM batteries.