I have a 2016 Octavia 2.0 TDI, and the alternator is currently not functioning. However, the car battery is fully charged, allowing me to start the car. I plan to take it to a mechanic, but I am concerned about the faulty alternator not charging the battery. My question is - if I start the car, will it stop running once the battery drains, or will it continue operating regardless of the battery charge level?

 

It should keep running just fine. Bear in mind that your ancillary systems wont work as the battery runs down, your power steering will die too as the battery discharges.

@robinwa as @petrolcan says, with the note that. once the alternator has been replaced, it might be good to have the mechanic scan the car and cancel every error message recorded, on the basis that the underlying cause of them was probably the alternator fault.

Hi, welcome.

 

Starting the car is only one part of the issue,  and not so draining as in past decades but a diesel does take more to start.  If the alternator is not topping up the battery then of course the battery will drain.  You can reduce the amount the battery drains by reducing the load on the battery with no or reduced use of the starter motor (deactivate start/stop), air-con, blower motor, heated anything, radiator fan (do not get the engine too hot), wipers and lights (where safe), anything you have added to the car, infotainment.

 

You need to fully recharge using an appropriate battery charger maintainer following the instructions for its use in the car's Owner's Manual and charger's instruction booklet.  You want to fully recharge the battery after each car use.

 

If activated the start/stop would be the first item to show low battery by not operating when it should, perhaps you may get all sorts of unexpected of messages and/or warning lights and unseen error codes, the computers do not like the battery in a low state of charge and may make you suffer for it.  When you have the alternator sorted as suggested get all error codes cleared. 

 

I do not know but I would guess if the power steering stops then you are very low and difficulty starting the engine may soon follow.

 

Be careful to check you do not accidently use electric when you do not need to or accidently leave any electric running,  Bear in mind the car's computers and alarm system run when the car is parled up so even more reason to fully recharge the battery and use a battery charger maintainer  to maintain the charge level.

 

I had an alternator failed whilst on a driving tour weekend and I would have been fine but I forgot to turn off my headlights once we got out of the mist, but this was on a very old car with very, verry little electric load and no computers at all (oh, for such days again).

 

Edited 3 November, 20241 yr by nta16
typos

Forgot to answer your question, yes once there is insufficient charge in the battery the engine will stop because the computers wont like it. "12 volt battery faults are the most common cause of breakdowns" and as your case it's very, very rarely the of the 12v battery (most usually the cause is owner/driver use. abuse and neglect of the battery). - https://www.theaa.com/breakdown-cover/advice/top-ten-breakdown-causes

 

Edited 3 November, 20241 yr by nta16
missing words