[DeTomaso] Alternator Options

[doug351c]

Mike,

My intention is to caution owners to not add more alternator ampacity than
is necessary.  Your burned wire harness was likely due to the ammeter.  The
Pantera ammeter has been known to have loose internal terminals and is a
known fire hazard if it has not been inspected for such.  I found that after
tightening my ammeter's terminals, it still needed a 16AWG jumper to make it
read correctly (as verified by an NIST traceable calibrated Hall effect DC
reading Amp meter).  Consider also that the 4AWG wire leading to and from
the ammeter has a continuous rating of only 60A not 100A.  If the voltage
regulator fails, it can tell a 100A alternator to provide maximum output
which can lead to a fire.  I do not recommend a 100A alternator in any
Pantera that has not had it's ammeter and associated cabling upgraded to
handle the increased output.  I would welcome SO Bills comments here.

Doug
  -----Original Message-----
  From: MikeLDrew at aol.com [mailto:MikeLDrew at aol.com]
  Sent: Saturday, November 27, 2010 10:58 PM
  To: doug351c at gmail.com; jskeane6 at gmail.com
  Cc: detomaso at realbig.com
  Subject: Re: [DeTomaso] Alternator Options



  In a message dated 11/27/10 22 30 3, doug351c at gmail.com writes:



    I know of other Pantera owners who've installed
    100A alternators and burned up their wiring harnesses.


  >>>I wouldn't necessarily assume that it's causative however.  Can you
draw a straight line between the alternator install and the wiring harness
issue?  I doubt it--there were probably other factors involved.  My Pantera
came to me with a burned wiring harness too, and a stock alternator.

  And that alternator didn't work worth a damn keeping the old battery
going; I could sit at a red light at night, with the fans, headlights and
A/C running, and if I didn't keep the rpm up, eventually it would kill the
battery and the car would quit.  I'd then have to push it to the side of the
road, turn everything off and wait for awhile for the battery to recover and
the car to cool off so the fans would shut off.  Not fun!



    >Excess alternator
    capacity is not necessarily a good thing.


  >>>Very true--but more Panteras than not are running 100A alternators now,
so I wouldn't consider that 'excess'.


    >As long as your ammeter shows a positive reading, your alternator is
keeping
    up with the load and this is an average thing so at idle it's OK to read
a
    negative as long as it reads positive with a few additional revs.


  >>>That depends on how long you drain the battery like that.  My ammeter
reads slightly positive even at idle with the fans running.

  Just because an alternator can produce 100A doesn't mean that it always
does so.  (Somebody correct me if I'm wrong).  Depending on the demands of
the electrical system, it can produce UP TO 100A.  If the demand isn't
there, the alternator doesn't put out any more juice than a lower-amp unit.
So it's not going to automatically pump all sorts of power into your car.
But if you have heavy loads on the electrical system, it should have enough
hump to keep you in the positive and keep from running your battery down.

  SOBill or somebody with some serious electrical smarts, weigh in here and
let me know if I'm all wet on this?

  Mike