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High voltage from alternator, overcharging from Lecce Neville

July 01, 2021, 11:25:06 pm

Today I learned alot about my alternator from the thread on low voltage from a FT's Lecce Neville alternator on today's forum.  That thread reminded me of this video done by a knowledgeable auto tech on his own rv, that was putting out high voltage, and causing many related issues.  I started watching his channel after watching him change his own fluid and filters on his Allison 3000 series transmission.  This video is not short, however, I still feel his diagnostic explanation gave me more insight into knowing how my alternator works.  I hope it does for you too.  Overcharging our batteries can drastically shorten the life of our batteries, thus my post.  Has anyone had this issue, and how did you correct the problem?
https://youtu.be/YXDG-mhG_XY

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Re: High voltage from alternator, overcharging from Lecce Neville

Reply #1 – July 02, 2021, 07:45:04 am

Number one cause of high voltage is a poor connection from chassis battery side of isolator the the SENSE TERMINAL.

That gives the alternator a false "lower than actual" input so it cranks up the alternator.

Sure, there can be other causes, but make sure that the sense terminal accurately reflects actual chassis battery voltage.  Lots cheaper than just throwing a new alternator on it.

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Re: High voltage from alternator, overcharging from Lecce Neville

Reply #2 – July 02, 2021, 08:35:21 pm

Wolfe, I appreciate your comment.  I believe he took a reading on the sense terminal and was also getting a high reading.  Your comment may save mine or others time in diagnosis.

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