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Alternator / voltage regulator issue

PostPosted: Tue Oct 10, 2017 6:20 am
by xvracer
I ran my last event for the year this past weekend. On grid for the Qual session I fired up the engine and ran through some basic data checks on my Co-Pilot2. Voltage was reading 17+. (That never happened before.) Should have cycled it, but did not and ran the 15 minute session. Yes, the battery vented...had to clean that up. After the session I checked voltage at the battery, but everything went back to normal. Reading 14.2v at the battery and Co-pilot. It was fine the rest of the weekend. I have the new style alternator. My questions:
1- Is this a failure mode of the Alt / VR that anyone has seen before?
2- What damage could have occurred in the electrical system by running at 17+ volts for 20 minutes?
3- Is the VR in the alternator re-buildable / replaceable?

Re: Alternator / voltage regulator issue

PostPosted: Tue Oct 10, 2017 1:12 pm
by breton
Voltage regulator problem. If it "solved" itself (meaning voltage output no higher than 14.5), it could have been an intermittent connection at the regulator, or a sign that it's about to fail.

You do not want to run with high voltage reading not only for impact to the battery, but potential risk to other electronics. The ECU would be my biggest worry, but since the operating specs are 6v-22v it's likely not an issue.

The regulator should be replaceable, but I don't have specific model information on the alternator so can't offer specific advice.

Re: Alternator / voltage regulator issue

PostPosted: Tue Oct 10, 2017 1:33 pm
by breton
Should confirm, but this may be the right part if you need a new voltage regulator: http://store.alternatorparts.com/f002g1 ... ifier.aspx. Looking back at earlier threads, I believe the Bosch part number for the alternator is: 0-124-120-009

Re: Alternator / voltage regulator issue

PostPosted: Tue Oct 10, 2017 7:48 pm
by xvracer
Thanks Bob.