Battery voltage is low

[Mears]

The voltage at my battery is pretty low when driving (around 13V). If I rev the engine, I can get it up to 13.4V or so. The battery is about 6 years old, but I'm not sure if this might be an indicator that the alternator is on its way out since the volts are low when the engine is running. Thoughts?

 

[LTC8K6]

If you can get to an Auto Zone, they will test your battery and charging system for you for free.

Typically, you'd have an idiot light on if your alternator was not working.

13.4v is low with the engine running, which would normally indicate an alternator problem, but it could still be an odd battery problem.

If your battery is really 6 years old, you need a new one anyway.