MK5 Golf GTI
All Things Mk5 => Mk5 General Area => Topic started by: OllieVRS on July 03, 2023, 11:03:18 am
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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:
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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?
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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.
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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.
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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.