Matronics Email Lists :: View topic - Max Alternator Voltage ?

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Max Alternator Voltage ?

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

markeypilot(at)yahoo.com
Guest

Posted: Sun Jan 03, 2010 2:12 pm Post subject: Max Alternator Voltage ?

We just returned from a 1.4 hour flight  (at) 0'F conditions.

it some cranking on the ramps at both ends of the flight legs to get going.

Upon returning, I noticed 15.1 volts (at) about 2-3 amps indicated.



Is this OK for a 60-A alternator?

What should be a max voltage under such circumstances before I have my EIS gives me an alarm? [user programmable value in the Grand Rapids unit]



Thanks in advance,



John in the Glasiar



Deep peace of the Light of the World to you.                                                             --A Gaelic  Blessing

       

         [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

rjquillin

Joined: 13 May 2007
Posts: 123
Location: KSEE

Posted: Sun Jan 03, 2010 4:39 pm Post subject: Max Alternator Voltage ?

At 14:09 1/3/2010, you wrote:

  	  Quote: 	
		  We just returned from a 1.4 hour flight  (at) 0'F conditions.

 it some cranking on the ramps at both ends of the flight legs to get going.

 Upon returning, I noticed 15.1 volts (at) about 2-3 amps indicated.



 Is this OK for a 60-A alternator?

 What should be a max voltage under such circumstances before I have my EIS gives me an alarm? [user programmable value in the Grand Rapids unit] 	


 John,

 You may want to consult your battery manufacturers' site for the ICAW sheet and owners manual.  In the TC world both Concorde and Gill have recommended charge voltages for their different battery types (flooded, AGM/VRGA) based on ambient temperatures.  

 This has been the topic of some lively discussions here on the list before you could find with an archive search.



 A chart in the Concorde manual suggests, for 0F/-18C a voltage of ~ 15.5 volts.



 Ron Q.



 

     [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jan 03, 2010 7:41 pm Post subject: Max Alternator Voltage ?

At 04:09 PM 1/3/2010, you wrote:

We just returned from a 1.4 hour flight  (at) 0'F conditions.

it some cranking on the ramps at both ends of the flight legs to get going.

Upon returning, I noticed 15.1 volts (at) about 2-3 amps indicated.



Is this OK for a 60-A alternator?



   We'd like to see it a tad lower but it's not a

   crisis either. I ran an alternator in my GMC

   van for years at 15.2 volts which didn't seem to

   be particularly abusive of the battery either.



What should be a max voltage under such circumstances before I have 

my EIS gives me an alarm? [user programmable value in the Grand Rapids unit]



   Trip calibration points for most OV protection

   systems is 16.2 +/-.2 volts.



   Get a second opinion from another known good

   voltmeter . . . a John Fluke instrument comes

   to mind as one potential 'gold standard'.



   If the bus is REALLY running that hot, it would

   probably be a good idea to do something to

   reduce it. What kind of regulator are you running?



   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Sun Jan 03, 2010 8:31 pm Post subject: Max Alternator Voltage ?

John,

 A proper voltage regulator, whether mechanical or solid  state, has temperature compensation built in.  The lower the ambient  temperature the higher the charging voltage allowed from the alternator.   Essentially,  the colder the battery, the higher the charging voltage must  be to get the proper chemical reaction with in the battery.  In really hot  weather, you will see the reverse; could see the charging voltage drop to under  13 volts.

 [quote]   ---

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 04, 2010 9:57 am Post subject: Max Alternator Voltage ?

At 10:28 PM 1/3/2010, you wrote:

  	  Quote: 	
		   John,

 A proper voltage regulator, whether mechanical or solid state, has temperature compensation built in.  The lower the ambient temperature the higher the charging voltage allowed from the alternator.  Essentially,  the colder the battery, the higher the charging voltage must be to get the proper chemical reaction with in the battery.  In really hot weather, you will see the reverse; could see the charging voltage drop to under 13 volts. 	


   We used to see temperature compensation of regulators

   when they were external to the alternator. Even the old

   electro-mechanical generator regulators had bi-metal springs

   to stiffen the spring rate at cold temps.



   As soon as the regulators moved inside the alternator,

   the regulator's sense of battery environment was

   clouded by alternator heating. We considered built

   in compensation on the B&C regulators and rejected

   the idea as greater potential for problems than

   potential for benefit.



   I suspect that the phenomenon Ron is reporting

   has more to do with a regulator problem than an

   expected reaction to temperature.



   Bob . . .    [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

rjquillin

Joined: 13 May 2007
Posts: 123
Location: KSEE

Posted: Mon Jan 04, 2010 10:40 am Post subject: Max Alternator Voltage ?

At 09:55 1/4/2010, you wrote:

  	  Quote: 	
		  I suspect that the phenomenon Ron is reporting

   has more to do with a regulator problem than an

   expected reaction to temperature.



   Bob . . . 	


 Thanks for reading the post Bob.

 Not sure I was reporting a problem, all's well with me,

 but rather attempting to provide some guidance WRT charge voltages,

 as suggested by battery manufacturers'...



 Ron Q.

 do not archive    [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum