[DeTomaso] Alternator test data

[jtaphorn at kingwoodcable.com]

David

That was a good post.  Thanks for taking the time to get actual measurements of the charging system's demands and testing the battery disconnect hypothesis.  Real data is good!  Cool scope.

JT
---- Tomas Gunnarsson <guson at home.se> wrote: 

=============
Thanks for the data David. If I interpret your scope pic correctly your
upper marker line is at 19.2 volts and the spike extends even a few
volts above that level (@ 5V/div). This is quite a lot of overvoltage so
some electronics might not like it. The least of my worries is the
alternator itself, it's probably good for it. Your consumption sheet
confuses me. Why don't the individual loads add up to 56A? It's like you
have a parasitic load that offsets all the individual readings. I did a
similar but not as detailed test myself over ten years ago.
 
Tomas

<-----Ursprungligt Meddelande----->
From: David D Fisher [fisher95020 at yahoo.com]
Sent: 16/9/2012 8:09:47 AM
To: Pantera mailing list
Subject: [DeTomaso] Alternator test data

Ok,  I promised this would be my last entry on this subject. I ran tests
today on my 1 wire alternator setup and am sharing with anyone
interested.
 
 
First I wanted to know how much current each system was drawing.  I put
it in a table for my future reference, and it's here if anyone has
interest.
 
Punch line,  I pull 56Amps with everything on.  I ran this at both 800
rpm and 2000 rpm
 
http://www.poca.com/index.php/gallery/?g2_itemId=38007
 
 
Probably more interesting,  I ran the test of what happens if you
disconnect the battery while the alternator is running.  Again run at
800 and 2000 rpm.
 
Punch line,  Voltage has a little spike but stays at 14.X volts and the
car (all the systems in the car) don't mind having the battery circuit
connected and disconnected.   NOTE: This is a one wire setup and you
should run your own test on your own alternator.
 
http://www.poca.com/index.php/gallery/?g2_itemId=38009
 
Scope trace of the spike for the EE's in the group (It's just as Tomas
suggested)
 
http://www.poca.com/index.php/gallery/?g2_itemId=38014
 
 
You might also find this interesting.   I was surprised what the factory
did to connect the ammeter circuit to the alternator circuit. 
 
http://www.poca.com/index.php/gallery/?g2_itemId=38011
 
 
A couple of notes:  I disconnected and connected the battery when 20A
was flowing in that circuit.  A fool proof test would do it at 70A, but
I'm pretty satisfied. 
 
Given these tests, I will go ahead and put a circuit breaker on the
ammeter circuit.  (I have more detail if anyone wants to email me
directly) and a 4guage line from the ammeter to the fuse box.   The
factory "wire merge" will get replaced with a terminal block.
 
It also looks like a 140A alternator was significant overkill as I'm
only consuming about 60A (if the battery is charged), but it has the
benefit of having enough juice for lots of stoplight to stoplight
putting around town without draining the battery.  I probably could have
gotten by with a 100A alt that puts out at least 40A at 800 rpm.
 
David
_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso
.

_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso