The battery may be the result, not the cause
A discharged battery cannot start the vehicle, but replacing it does not correct an alternator problem, high cable resistance, an abnormal key-off draw or repeated short-trip use that never restores the charge.
A complete starting and charging test
The battery should be charged and tested under appropriate conditions. The technician can then measure cranking performance, cable voltage drop and charging-system operation.
- Battery condition and state of charge
- Starter demand and cable resistance
- Alternator output and control
- Abnormal key-off current draw when indicated
Intermittent electrical concerns
Some drains occur only after a module wakes up or fails to go to sleep. Advanced intermittent electrical concerns are best scheduled at Jonestown, while both locations can perform general battery and charging tests within their vehicle coverage.
A charging warning with dimming lights, stalling or loss of critical systems can make the vehicle unsafe to continue driving.
Common questions
Can a bad alternator ruin a new battery?+
Incorrect charging can leave a battery undercharged or expose it to abnormal conditions. The full system should be tested.
How long does parasitic-draw testing take?+
It varies because some vehicles require time for modules to enter sleep mode and intermittent drains may need extended observation.