Car Died, Faulty Battery or Alternator?

[Lawrence25]

So my partner and I have been away on holiday for 10 days and we left her car.

It started up fine yesterday but she only drove for about 10 mins in the morning and 10 mins in the afternoon.

This morning it would refuse to start. I know this isn't enough time to charge the car but my main question really was, could the battery be weak or a messed up alternator as I've noticed when sitting in her car when she accelerates her internal fan blowers get louder and her lights get brighter in the past.

We are going to jump start it and see about driving it for 30 minutes to get it sorted but we need to sort something out for the long run.

[anonymous-user]

Sounds like it could be a bit of both, but having been sat in the cold and then a couple of short runs it's not surprising the battery is struggling. Get it charged and see how it goes.

[Lawrence25]

charltjr said:

Sounds like it could be a bit of both, but having been sat in the cold and then a couple of short runs it's not surprising the battery is struggling. Get it charged and see how it goes.

That's what I thought, my concern is the lights getting brighter. Possibly a faulty diode?

[Penelope Stopit]

Lawrence25 said:

So my partner and I have been away on holiday for 10 days and we left her car.

It started up fine yesterday but she only drove for about 10 mins in the morning and 10 mins in the afternoon.

This morning it would refuse to start. I know this isn't enough time to charge the car but my main question really was, could the battery be weak or a messed up alternator as I've noticed when sitting in her car when she accelerates her internal fan blowers get louder and her lights get brighter in the past.

We are going to jump start it and see about driving it for 30 minutes to get it sorted but we need to sort something out for the long run.

The fans will run faster and the lights get brighter when you rev the engine, the difference will be more noticeable if the battery voltage is lower than it should be
Something may be slowly draining the battery or the battery could be faulty, get the battery tested and have someone check if there is a small permanent drain on the battery that shouldn't be there

Edited by Penelope Stopit on Thursday 5th January 14:33

[PaulKemp]

If you've got a multimeter once running alternator should provide 13.8 to 14.3 volts measured at the battery
Charged battery car not running should be 12.6 to 12.8
Battery voltage below 12.4 needs charging