[DeTomaso] Amp gauge

[shawkins777 at comcast.net]

I fall into the ammeter more usefull information side, you can limit the current through the dash with a properly sized shunt/gauge. 

Steve 


----- Original Message -----

From: "Kirby Schrader" <kirby.schrader at gmail.com> 
To: MikeLDrew at aol.com 
Cc: guson at home.se, detomaso at realbig.com, "mikael hass" <mikael_hass at mail.tele.dk> 
Sent: Friday, May 18, 2012 2:25:54 PM 
Subject: Re: [DeTomaso] Amp gauge 

Gee, Mike, 

I knew how an ammeter worked before you were even born! No need to tell me. 
:-) 
The GT40 _was_ wired wrong and Superformance sent out a wiring 'fix'. 

If you want both, by all means do so! 
There has been many a thread on this forum since it started back in 
the mid-90's. 

Up to you what you use. I used to be a 'dyed in the wool' ammeter fan. 
I have converted to voltmeters. 

Kirby 

On Fri, May 18, 2012 at 12:45 PM,  <MikeLDrew at aol.com> wrote: 
> 
> In a message dated 5/18/12 9 41 35, kirby.schrader at gmail.com writes: 
> 
> 
> 
> I disagree and can not at all see how this approach is valuable... 
> That's the way my GT40 came 'incorrectly' wired. 
> As you turned things on (fans came on, A/C compressor, etc. etc.), 
> the ammeter kept climbing as it measured all the loads. Do you really 
> care? 
> I suppose for bragging rights. Look at me!!!! 83 amps!!! Woohoo! 
> 
> 
> That's not how an ammeter is designed to work, and as you said, your car was 
> wired *incorrectly*. 
> 
> If the car is shut off and you start adding loads (turning on lights, fans 
> etc.) then the ammeter registers in the negative, not positive.  When the 
> car is turned on and the alternator is charging, ideally the charge should 
> be slightly higher than the load, so that the gauge indicates slightly 
> positive.  When you first start the car, if your battery is weak, it will be 
> drained quite a bit, so the ammeter will reflect a high state of charge for 
> a minute or two as the charging system rapidly returns the battery to a 
> fully charged state, and then it will come down to show a slight charge 
> (ideally).  If your idle speed is too low, you might show a slight discharge 
> at idle with all your components (lights/fans etc.) running. 
> 
> Sounds like your car had both the supply AND the loads wired on the same 
> side of the ammeter?  That would deliver crazy readings for sure. 
> 
> My point is that it's senseless to take high-load components and wire them 
> outside of the ammeter so that the ammeter never registers their draw when 
> running.  It's like partitioning your fuel tank so that the fuel gauge only 
> registers part of the fuel you have on board.  Doing so guarantees that 
> you'd never know exactly how much fuel you have.  What would the point of 
> that be? 
> 
> An ammeter will instantly indicate a charging system failure because the 
> needle will displace into the negative side, which is easily apparent.  A 
> voltmeter is much more subtle; it will show 12.5 or 13 volts when all is 
> good, and will ALSO show 12.5 or 13 volts if your alternator fell out of the 
> car, because it's just showing the state of charge of the battery. 
> 
> The common fallacy is that the voltmeter tells you about your alternator. 
> It doesn't tell you JACK about your alternator, it only tells you about the 
> state of your battery.  An AMMETER is the only gauge that tells you about 
> your alternator, because it instantly informs you as to whether it is 
> charging the battery, or if the battery is being discharged. 
> 
> Over time, if your alternator clatters onto the roadway, your voltmeter will 
> drift imperceptibly lower as the battery drains, but at a glance it will 
> still look healthy.  When it gets to 11.5 volts or whatever, you'll sputter 
> to a stop with a 'dead' battery. 
> 
> It would be ideal to have both a voltmeter and an ammeter, but given the 
> choice I'd take an ammeter any time. 
> 
> Mike 
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