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alpinelakespilot2000

Well Known Member
I just switched out my failed Plane Power for an new, but old school vans 35A 14814 alternator with a new 1975 ford/VR166-type external regulator. Wired with a B&C OV module per B&C/Aeroelectric schematics.

I'm showing 14.4V on my Dynon which equates to 14.7V on the main buss (my Dynon like most I've heard about reads low--about 0.3-0.4V in my case). The volt meter on my 696 confirms my buss is getting 14.7V. My fluke multimeter also confirms the 14.7 on the main buss. I know Odyssey batteries prefer higher voltage than traditional a/c batteries but this is quite a bit higher voltage than I got with my Plane Power (about 13.8V on the Dynon/14.1V actual on the buss) The upper limit of my green range was 14.6V, I think just because the Dynon came with that preset. I'm a bit worried that in flight I might occassinally see higher voltage and then have to wonder if I should abort a flight.

1. Should I be good with this voltage, especially given that it's feeding an a Odyssey? If so, at what higher voltage should I start to get concerned?

2. Should I find an adjustable voltage regulator so that I can adjust it downward? If so, any off the auto store shelf models you can point me too?

3. Should I be troubleshooting further? If so, any suggestions on where to start?

Thanks for any thoughts.
 
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I've actually seen a bit higher than 14.7 (depending on which device I'm looking at), have always gotten good battery life.
 
I am the odd man out - - while 14.7 is fine for the odyssey, it is not making sense that an old school regulator is putting out 14.7 volts. It should have been 14+0.2volts for the PbA flooded plate batteries of that day. I might be inclined to check further on why it is regulating to that voltage.

Not saying there is any specific issue with leaving it like it is, just seems out of spec.
 
Thanks all for the input. I have pretty much Sam's exact setup, so it sounds like I'm ok, even with 14.7V That said, like Bill mentions, I too have wondered how I could get 14.7Vout of an automotive alternator and automotive regulator. Maybe there are some other things I can check. (?)
 
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Maybe you're feeding the alternator field with a lower voltage, for example from the E-bus. That would do it. 0.7V drop through the diode would raise your alternator output voltage to 14.7V.

Lenny
 
Update: replaced my Cessna split master bat/alt fld master switch with a regular switch from B&C and this eliminated a lot of resistance. Now I get a more normal ~14.0V on the Dynon and about 14.3 at the main bus. Problem seems to be addressed.
 
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Your in the ball park

Most onboard volt meters are not that precise. They can range two or three tenths up or down. I would not get to concerned at being two tenths over on a reading like this. If it were to be reading 15.0 volts, I may start checking to see if I was slightly over charging a little. Your well within the ball park. hope this helps, Yours R.E.A. III #80888
 
Steve,

The regulator is looking for field voltage as a reference. So if it sees a lower voltage than its setpoint it will raise the alternator output until it sees the setpoint voltage on the field. So your regulator's setpoint is either higher or your field voltage is lower. You can measure the field voltage at the regulator to find out which is the case.
Anyway, Odyssey specs 14.7V as the upper limit of charging voltage, so you should be fine as long as you don't go over that.

Page 12
http://www.odysseybattery.com/documents/US-ODY-OM-012_1014.pdf

For applications where an alternator is present, the alternator must deliver between 14.0V and 14.7V when measured at the Battery?s
terminals. Consult the ODYSSEY battery technical manual or owner?s manual for any necessary temperature compensation. Alternators that do not have a regulated
charge between 14.0V and 14.7V (no lower than 14.0V and no higher than 14.7V) will cause early failure of the Battery. Use of such alternators with the Battery will also void the Battery?s warranty.
 
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