Battery Reads 12V but Won't Run Anything? Troubleshooter
12V on the meter doesn't mean the battery is OK.
Resting voltage alone doesn't show capacity. A load test does. Work through one question at a time. You can go back or start over whenever you like.
Your answers so far
Safety: this troubleshooter is general information for low-voltage DC learning circuits. 240V AC mains can kill: in Australia, work on mains wiring must be done by a licensed electrician. Disconnect power before you touch wiring.
Related guides
Lesson
What a Battery Voltage Reading Can and Cannot Tell You
A multimeter reading tells you a battery's voltage, not its health. Learn what resting voltage, surface charge, load and chemistry mean for a reading.
Read guide →
Lesson
How Batteries Work: Voltage, Capacity and Energy
What volts, amp-hours and watt-hours mean on a battery, why usable capacity matters, and how to compare batteries of different voltages properly.
Read guide →