Increased Alternator Output at Idle - Opinions

[Nacho-RT74]

eeeehm, I have a courier service in Florida and MAYBE will be winning an auction soon.

IT IS ALREADY TESTED THE OUTPUT AND NOT JUST A POSTED AND EXPECTED SPEC ?

[GMP440]

Just go to an auto parts store and get an alternator for a 72 Chrysler Neuport. That one is rated at 65 amps. It has the correct style round back case.
Also, its a two field alternator. You only need to use one field and ground the other field.  Easy to fix.  Just remove the screw holding in one of the fields, put a washer on making sure the washer makes contact with the case as you put the screw back.  This alternator will work well with your existing wiring and no need to switch to a 70' and up style voltage regulator.  I've been using this alternator on my 68 Dodge Coronet for many years and it really improved the whole performance of the electrical system.

[68neverlate]

eeeehm, I have a courier service in Florida and MAYBE will be winning an auction soon.

IT IS ALREADY TESTED THE OUTPUT AND NOT JUST A POSTED AND EXPECTED SPEC ?

The shop advised me that's what they got from their bench test after assembling... so it should be the real McCoy (not just the posted or spec).  I might just bring it to another shop (that provides free testing) on the way to work one day before installing to have the output confirmed...    

[Nacho-RT74]

Just go to an auto parts store and get an alternator for a 72 Chrysler Neuport. That one is rated at 65 amps. It has the correct style round back case.
Also, its a two field alternator. You only need to use one field and ground the other field.  Easy to fix.  Just remove the screw holding in one of the fields, put a washer on making sure the washer makes contact with the case as you put the screw back.  This alternator will work well with your existing wiring and no need to switch to a 70' and up style voltage regulator.  I've been using this alternator on my 68 Dodge Coronet for many years and it really improved the whole performance of the electrical system.

still not enough buddy although is true is a real improvement

I already have the 78 amps lates 70s alt, and still not enough ( 40-45 amps at iddle ) fairly stock look alt, although not exact for the year

[HeavyFuel]

Hate to put up this link for another mopar website....but this is some good information.

http://www.allpar.com/history/mopar/electrical.html

[b5blue]

That's the Denso 120 amp I got from Mancini shown in that link.   

[68neverlate]

Hate to put up this link for another mopar website....but this is some good information.

http://www.allpar.com/history/mopar/electrical.html

Yup... saw that too before deciding on the modifications I'm carrying out.  I wanted my ammeter to continue to work afterward so my mods aren't quite the same as what these guys suggest.  Good info though....   

[68neverlate]

Well, it took a little longer than I thought, but I finally finished all the wiring modifications in my '68 and am more than happy with the results!! 

My goal at the start of all this was to increase the output of my original '68 alternator at idle to the point where the car was completely supplied by the alternator (no discharge of the battery) even when everything was turned on and car was at idle.  I wanted to do this without bypassing the ammeter in the dash so that it still would tell me the state the car was in (in the event a battery or alternator goes down), make all my wiring safe to handle the extra power of a high output alternator (100 amps - stock wiring is only intended to handle 46 amp max) and do that all while keeping to an original look as much as possible under the hood and in the cab. 

I did have to make a few revisions to my planned modifications (see further down this thread) that were dictated by the max output of the alternator that I ultimately got built for the car (I asked for an 80 amp max alternator and the shop built a 100 amp max alternator). 

1)  Instead of running 10 gauge wire from my alternator to the splice, to the alt side of the ammeter and from the battery side of the ammeter to the starter relay (bypassing the bulkhead connector), I used 8 gauge (to be able to handle the worst case scenario - 100 amps travelling between battery and splice or from alternator to battery - without a risk of melting wires). 
2)  I added a second, fused (30 amp) ammeter bypass (to split the current over three routes to be able to handle a maximum current of 90 amps between the battery and splice or from alternator to battery without blowing any of the 30 amp fuses in the bypasses or ammeter loops).
3)  I had a new battery cable made that included an 8 gauge piggyback wire from the positive battery terminal to the starter relay (to be able to handle the worst case scenario - 100 amps travelling between battery and splice or from alternator to battery - without a risk of melting that section of  wire). 
4)  I used a 12 gauge fusible link between the ammeter and the starter relay (two sizes smaller than the 8 gauge wire I was protecting).
5)  I upgraded all the wiring from the splice out to the ignition, headlight switch and fuse box to 10 gauge (just because I could!   ).

When I first fired up the engine after everything was in place, I saw a slight charge state on my ammeter for the first time since I owned my car (the alternator was fried when I bought it), however, my ammeter was pulsing (needle was constantly fluctuating about 1/4 of an inch) and all my lights (headlights, dashlights, brake lights, tail lights etc.) were pulsating/flickering as well.  At no point was the needle ever on the discharge side of centre on my ammeter, however, so I had plenty of power at idle.  I checked the field side of the voltage regulator (the original points style regulator) and found it was sending a fluctuating signal into the alternator rotor... garbage in, garbage out.  So I replaced that regulator with another points style regulator... same results.  So it appears that while the old points style regulators will work with the higher output alternator, they do a really lousy job of regulating voltage.  I purchased and installed an electronic voltage regulator, and all the pulsating/flickering went away.  I warmed up the car and kicked the choke out so it was idling at about 700 rpm, turned everything I have in the car on max (no aftermarket stuff but the car does have factory A/C) and the needle was rock steady and still at centre on the ammeter.  It move slightly each time I turned something on, but never went left of centre... no more discharge state!!     So it appears all the time and effort was worth the result.   

I have pictures of the work that are still in the camera that I'll post up in the next couple of days.  Thanks to all who contributed through this thread... appreciate your interest and input guys! 

         

[flyinlow]

Lot of work ,but sounds like it was worth it. 

[68neverlate]

Lot of work ,but sounds like it was worth it. 

Yeah... it's nice to see the results at the end for sure.  Wasn't too bad for time... I tinkered because it's basically in for the winter so it took longer than it would have if I'd just have had at 'er!     

Cheers,   

[68neverlate]

Here are the pictures I promised earlier today...

The 100 amp alternator (custom stator, stock rotor)... looks like the original. 




I wanted to hide as much as possible so located the power distribution bars (one mount, twin bars) just above the steering column on the firewall and the fuse block containing the three fuses in the two bypass and one ammeter loops up high on the side of the vent box.

[68neverlate]

More pics...

[68neverlate]

And finally, I thought I'd throw this one in... a very proud Fido at home in the back seat of the Charger with the Flowmasters thundering away beneath his feet!   

[ChargerST]

Nice work! but due to the ammeter bypass you probably wouldn't see much of a needle movement on the ammeter if the battery is charging - might be sufficient current flow to indicate the direction though.

[68neverlate]

Appreciate the pat on the back ChargerST...     

The needle deflection is really not that bad... I estimate that each of the three loops is taking about 1/3 the current, so the ammeter should be deflecting at about 1/3 of what it would have prior to the 2 bypasses being added.  And that's pretty close to what I'm seeing...

When my power output was pulsating (before the electronic regulator was installed), I saw a fluctuation of about a 1/4 of an inch at the end of the ammeter needle... a fair amount of movement.  As I indicated previously, I wasn't as much concerned about an accurate reading on the ammeter as I was just wanting to know what state the charging system was in (charge or discharge).  Knowing that I'm at about 1/3 deflection on the needle, I can always just multiply my ammeter reading by 3 to get an approx current flow indication if I wanted to...

Appreciate your interest in the thread...            

[Brass]

Very sharp - and Fido looks happy!