Hey Dave;
    I had a stock alternator internal regulator fail high and as best I can remember it was always charging ~14.x volts previous to failure. I was lucky in that I was just taxing up to the hanger  when I saw it at ~19volts and climbing so I quickly shut down.
    When designing my system I'd read all of Electric Bob's warning about internal regulation, but I just figured that I'd never had a problem in all my years of driving so what were the odds? Not much, yeah right. When I went to buy a replacement, I found it was going to cost ~$40 and it wasn't in stock and would have to be ordered, but for $8 I could buy the Ford external regulator that Bob recommends and they had at least a dozen in stock. So I built the crow-bar circuit that Bob recommends and I converted my alternator to an external regulation (pretty easy to do)
Glad I did it, even though I'm not exactly putting up the hours now.
    Maybe you don't have a regulation issue, but if you do , you might want to consider converting.

Todd    (almost finished Harley generator install, pics coming soon)

On Sun, 2009-06-14 at 16:21 -0700, David Leonard wrote:

Today retuning from my flight my voltmeter started to complain "check voltage".  The bus voltage was reading between 14.2 - 14.6 volts.  Right after shut down the battery voltage was reading 13.3 volts.

 

Is this a sign of impending over voltage failure of the regulator? 

I am using the stock 70 amp alternator.  Do I need to replace it right away?  Use an external regulator?  Is it safe to watch it for another flight or two and see what it does?  Is it possible that oil mist could have gummed things up a little and spraying some contact cleaner into the alternator might do the trick?

 

How much voltage is too much before I need to land right away?

Thanks all.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net