Symptom guide
Car Battery Keeps Dying
How to separate a bad battery from charging problems and parasitic drain.
Quick answer
Repeated dead batteries usually come from an old battery, alternator undercharging, loose connections, or an electrical drain while parked.
Most likely causes
- Weak battery
- Alternator not charging
- Parasitic draw
- Loose terminals
- Short trips not recharging battery
Basic driver checks
- Check battery age.
- Test voltage after sitting overnight.
- Look for lights staying on.
- Check charging voltage when running.
DIY diagnostic path
- Do not keep jump-starting without testing.
- Clean and tighten terminals safely.
- Have battery load tested.
- Use parasitic draw testing if battery and alternator pass.
Common mistakes
- Replacing alternator without testing
- Ignoring glovebox or trunk lights
- Using the wrong battery size
What to tell the mechanic
Ask for battery, charging, and parasitic draw tests in that order.