Make a donation

Author Topic: Alternator Recommendations?  (Read 663 times)

Offline OllieVRS

  • Always Involved
  • ****
  • Thank You
  • -Given: 16
  • -Receive: 16
  • Posts: 329
Alternator Recommendations?
« on: July 03, 2023, 11:03:18 am »
It seems like my alternator's been on its way out ever since I accidentally shorted it because I forget to disconnect the battery while taking it out for a thermostat job.

Running voltage is 13.7-14.2V depending on factors like RPM and lights etc. When car is turned off voltage eventually settles at 12.2V. Battery was replaced a year ago with a new OEM VW 72AH one.

All my voltage readings are taken from my Sony stereo.

Wondering wether to go for OEM, aftermarket or used?

Cheers  :smiley:
'06 Skoda Octavia vRS TFSI

Offline OllieVRS

  • Always Involved
  • ****
  • Thank You
  • -Given: 16
  • -Receive: 16
  • Posts: 329
Re: Alternator Recommendations?
« Reply #1 on: July 05, 2023, 12:59:05 pm »
Measured battery with a volt meter after 4 hours of standing. It's at 12.3V.

Am I right in thinking that even with a weak alternator it should be able to charge a battery to 12.6V? Could the battery perhaps be at fault?
'06 Skoda Octavia vRS TFSI

Offline Octoparrot

  • Won't Shut up.
  • *****
  • Thank You
  • -Given: 8
  • -Receive: 102
  • Posts: 999
    • Email
Re: Alternator Recommendations?
« Reply #2 on: July 05, 2023, 06:11:44 pm »
I'd say your battery is more likely at fault. A healthy charged battery should be over 12 volts. The running voltages seem ok to me.

Offline OllieVRS

  • Always Involved
  • ****
  • Thank You
  • -Given: 16
  • -Receive: 16
  • Posts: 329
Re: Alternator Recommendations?
« Reply #3 on: July 07, 2023, 12:16:25 am »
I'd say your battery is more likely at fault. A healthy charged battery should be over 12 volts. The running voltages seem ok to me.

You're probably right. Took the battery out, using a halfords car battery charger, charged it for 6 hours. Voltage was a 12.5. Remeasured next morning, without anything even having have connected anything and it was at 12.2 again.

Phoned my VW dealer that I got the battery from last year about a warranty. Said he'll put in a request with the Skoda dealer as I have a Skoda, and it's up to them to honour the warranty (???). Despite me buying the battery from the VW parts department at the dealership  :thinking:. But on a positive note he said that if Skoda doesn't honour it, he's personally ordered in a replacement battery that he can give me that will arrive Monday, a.k.a being shipped in from the UK as they don't have any on hand.

'06 Skoda Octavia vRS TFSI

Offline pudding

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 2
  • -Receive: 690
  • Posts: 8353
Re: Alternator Recommendations?
« Reply #4 on: July 07, 2023, 08:46:03 pm »
I'd say your battery is more likely at fault. A healthy charged battery should be over 12 volts. The running voltages seem ok to me.

Agreed.  I wouldn't be wasting money on an alternator based on those engine running voltages.

A new battery holds 12.6V for days.  If it's dropping to 12.2 over night, it's got a bad cell or 2. It is more likely that didn't like the short circuit over the alternator.


2007 ED30 | 2009 TDI 140 | 2016 BMW 330D