[DeTomaso] Alternator found

Thu Sep 13 20:28:20 EDT 2012

Funny, that is what I had bought and was going to install.
I was going to instal it on the lead going from battery to the amp meter, I wish I had.

I had been cranking the engine over a few times as I have still not got my car running, then smoke poured from the alternator.
I had jump leads on at the time so I got it disconnected quickly.
The original alternator or regulator had shorted out.
It also cooked the amp meter even though the connections were all tight.
It certainly was was flowing a lot of amps, even the 4ga wire was hot.

I didn't put that breaker in as I did not want to put the ends on wires and I had not easy place to put it.
I now have got breakers like these installed..
http://www.amazon.com/Stinger-Direct-Connection-Circuit-Breaker/dp/B004YRA4QU/ref=sr_1_3?s=automotive&ie=UTF8&qid=1347581392&sr=1-3&keywords=stinger+breaker

They are easier to instal, waterproof and you do not need to put cable ends on.
I also put a 135 A unit also in the cable to my new alternator.

I have an 80A and 100A Stinger breaker for sale with 4 of the covers, a good price if anyone is interested.
http://www.hifisoundconnection.com/Shop/Control/Product/fp/vpid/1333041/vpcsid/0/SFV/30046 
This is the style that requires the cable ends.

On Sep 13, 2012, at 6:47 PM, David D Fisher <fisher95020 at yahoo.com> wrote:

> In the end I think I will put a 4 gauge cable from the Alt to the fuse box and install one of these resetable circuit breakers on the ammeter circuit in the event that circuit ever gets up to 70Amps. 
>  
> Seems like that should put an end to the worries, keep the stock look and has the bonus of cutting off all battery power with a push button.   I suppose it makes for a lightweight theft deterrent too if you want to kill power to the ignition bus.
>  
> http://www.amazon.com/Bussmann-Hi-Amp-Circuit-Breaker-Amps/dp/B0024JKT9W/ref=pd_luc_sim_03_01_t_lh
>  
> 
> David
> 
> From: Brian Dudley <bd8134 at gmail.com>
> To: John Buckman <jb841 at cox.net> 
> Cc: David D Fisher <fisher95020 at yahoo.com>; "detomaso at realbig.com" <detomaso at realbig.com> 
> Sent: Thursday, September 13, 2012 1:13 PM
> Subject: Re: [DeTomaso] Alternator found
> 
> On Sep 13, 2012, at 3:42 PM, John Buckman <jb841 at cox.net> wrote:
> 
> > David,
> >
> >> Sorry if this had been hashed over many times before...
> >
> >
> >>>> No problem.  It's good to review from time to time.
> >
> >> LET'S SEE IF I HAVE THIS CORRECT...
> >
> >
> >> 1) Run a 4 or 2 AWG wire on the 9' run from the Alt to the Fuse block.  This is the most likely wire to overheat as it will carry the full Alt output in the times when both the battery is low and the consumers are on full blast.
> >
> >
> >>>> Any increase in wire size helps.
> 
> I ran a new 4ga wire as above.
> I have added Jon Haas's fuse panel and ignition relay which all feed
> off where the 4ga joins the old 8ga which feeds the amp meter then to
> the battery.
> >
> >> 2) Live with the 8 AWG from the fuse block to the Ammeter but clean the terminals, put copper and star washers on and tighten up well.  Per SOBill's note and the wiring diagrams, this circuit only sees the current going to and from the battery.
> >
> >
> >>>> Just remember that with a low battery and very few consumer on, most of the alt's current will be going back to the battery via that 8 AWG wire.
> >
> 
> A 150 Amp alternator may put out 100 Amp at idle and would be too much
> if using any of the alternator to battery wiring, including most
> likely the amp meter.  Better to use a 125 or 105 Amp alternator which
> may put out 85 or 75 Amp at idle. You would still need to replace the
> "9 foot" wire at minimum.
> Using a larger pulley on a large output alternator could also work if
> not wired as a 1-wire.
> >> Assuming a dead battery and all consumers on, the Alt is working at full tilt, sending (for sake of argument) 150A down the wire to the fuse block.  From there the current splits with part of it going off to run consumers (through numerous wires) and part going through the ammeter to try and charge the battery.  Only part of the current is going through the ammeter circuit and can probably live with 8AWG.
> >
> >>>> Yes (see previous comment).
> If large output alternator you could have trouble.
> 
> >> 3) Given that the starter circuit does not go through the ammeter, we dont have to worry about it.
> >
> >>>> Correct.
> If you decided to use a high output alternator (>130A) and replaced
> the wire from alt to battery, with the size of wires going to amp
> meter etc, it might be best to go to a volt meter or go without. A
> simpler way is to just run the alt wire straight to the feed on the
> starter solenoid and make everything easier.
> >
> >> 4) This still leaves 2 potential fire hazard cases.  The first is when your battery is dead and your alternator is trying to push whatever the battery will take through the ammeter circuit.  I'm not enough of a battery charging expert to know, but I am guessing this could be hundreds of amps, probably about the same as the battery is capable of delivering.
> >
> >>>> The alt won't produce more than its rated current (+/- a small percent), and the battery (when low) will take all that it can get.
> >
> This is where you need to be careful. If you have a 100 - 125 Amp
> alternator with upgraded cables, if you do not increase your engine
> speed over idle and you wait until your amp meter has moved down from
> being pegged at +75, you might be ok.
> A higher amperage alternator (with >95 Amp idle), decreasing the
> alternator pulley size, not increasing wire size or increasing engine
> revs while battery is discharged could cause wiring problems.
> >> Note, that it doesnt matter if your consumers are on - they are on a seperate circuit, but it could be fatal if you are trying to boost someone else from your dead battery as the alternator is now trying to both charge your battery and the other guys, all through the ammeter circuit.  Soution here: Never boost with the  Alt on (engine running) .
> >
> >>>> If the engine is running on the donor car (and its alt is working), then the donor car's alt will be trying to charge the dead battery.  When the car (with the dead battery) is started, both alts will be trying to charge the dead battery.
> >
> 
> I would think you would be better off starting your car before jumping
> starting another. Keep your car at idle and watch the amp meter. If
> you have an alternator with <95 Amp output at idle with upgraded wire,
> it should be okay for a short duration.
> Starting your car after jump starting another could drain your battery
> and require you to idle for a while until the amp meter dropped to a
> reasonable level.
> >> 2nd hazard case, (which could happen with either a hi output or low output alternator).  Your alternator is not producing at all, and you have all consumers on.  You bought a nice hi output battery and it is now trying to power all the consumers through the Ammeter circuit because the Alt is doing nothing.  It you added a lot of consumers (fans, etc) this current need might exceed the Ammeter wiring.
> >
> >>>> Correct.  If possible, turn off some of the consumers.
> >
> >> Seems like these last two cases are fairly remote, but one would have to be aware of them.
> >
> >>>> Correct, but they do happen.
> >
> > John
> >
> >
> >
> >
> >
> >
> > On Sep 13, 2012, at 9:37 AM, David D Fisher wrote:
> >
> >> John,
> >>
> >> I echo Chucks comments... good info.
> >>
> >> Sorry if this had been hashed over many times before...
> >>
> >>
> >>
> >> I guess if one was to design the wiring upgrade based on a pareto of likely failures you might do the following (for a later car)...
> >>
> >> LET'S SEE IF I HAVE THIS CORRECT...
> >>
> >> 1) Run a 4 or 2 AWG wire on the 9' run from the Alt to the Fuse block.  This is the most likely wire to overheat as it will carry the full Alt output in the times when both the battery is low and the consumers are on full blast.
> >>
> >> 2) Live with the 8 AWG from the fuse block to the Ammeter but clean the terminals, put copper and star washers on and tighten up well.  Per SOBill's note and the wiring diagrams, this circuit only sees the current going to and from the battery.
> >>
> >> Assuming a dead battery and all consumers on, the Alt is working at full tilt, sending (for sake of argument) 150A down the wire to the fuse block.  From there the current splits with part of it going off to run consumers (through numerous wires) and part going through the ammeter to try and charge the battery.  Only part of the current is going through the ammeter circuit and can probably live with 8AWG.
> >>
> >> 3) Given that the starter circuit does not go through the ammeter, we dont have to worry about it.
> >>
> >> 4) This still leaves 2 potential fire hazard cases.  The first is when your battery is dead and your alternator is trying to push whatever the battery will take through the ammeter circuit.  I'm not enough of a battery charging expert to know, but I am guessing this could be hundreds of amps, probably about the same as the battery is capable of delivering. Note, that it doesnt matter if your consumers are on - they are on a seperate circuit, but it could be fatal if you are trying to boost someone else from your dead battery as the alternator is now trying to both charge your battery and the other guys, all through the ammeter circuit.  Soution here: Never boost with the  Alt on (engine running) .
> >>
> >> 2nd hazard case, (which could happen with either a hi output or low output alternator).  Your alternator is not producing at all, and you have all consumers on.  You bought a nice hi output battery and it is now trying to power all the consumers through the Ammeter circuit because the Alt is doing nothing.  It you added a lot of consumers (fans, etc) this current need might exceed the Ammeter wiring.  Of course this isnt going to last long as your battery will soon be dead.  Seems like these last two cases are fairly remote, but one would have to be aware of them.
> >>
> >>
> >> Thoughts?
> >>
> >> David
> >>
> >> From: John Buckman <jb841 at cox.net>
> >> To: detomaso at realbig.com
> >> Sent: Thursday, September 13, 2012 8:39 AM
> >> Subject: [DeTomaso] Alternator found
> >>
> >> Anyone care to guess how long the run is from the alternator through the ammeter and to the battery?
> >>
> >>
> >>>>> Early cars:  ~25'  Alt to ammeter to starter soleno
> >>>>> Later cars:  ~20'  Alt to ammeter to battery.
> >>
> >>>>> The tap (splice) for the fuse panel, ignition switch, and headlight switch is ~9' from the alternator.
> >>
> >>>>> The original ammeter wires (at least on the early cars) were 8 AWG.
> >>
> >>>>> One must remember that, when sizing wires, heat generation / dissipation can be a major concern.
> >> The more current (amps) that passes through a given size wire, the more heat is generated, and the more
> >> heat that is generated, the more the resistance (in that wire) increases, and as the wire's resistance increases,
> >> so does the voltage drop.
> >>
> >> Selecting a wire with a higher insulation temp rating is always a good idea, but NOT a good idea if you are
> >> selecting that wire size based upon a given current (amps) at that (high) temp.  Wires in bundles have a much
> >> slower heat dissipation rate than a wire that is run by itself.
> >>
> >> Tefzel (aircraft) wire is an excellent choice, although expensive.  It can withstand 200* C (392* F).
> >>
> >> John
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