Alternator Questions

[Needa68]

I've maxed out the stock alternator in our 68 by adding an electric fan. I believe the alternator is a 60 amp (?), single field, externally regulated unit.  I'm not sure about its amperage rating because I have been unable to cross reference the numbers on it to an amperage rating.

My hope is that it is either a 37 or 45 amp unit and that if I get a replacement 60 amp unit it will carry the load. I've ordered the replacement unit! If the replacement unit won't carry the load I need to go to Plan B. The problem is I don't have a definitive Plan B.

I've read about upgrading to new alternators but I'd like to retain the stock appearance of both the alternator and the external regulator for a couple reasons. First is the appearance factor but foremost is that the existing wiring has been modified. I installed a "Harness Preserver" (HP) a couple years ago which I do not wish to remove. As part of the HP mod a new cable was installed between the alternator and the starter relay. Additionally, a relay was installed between the voltage regulator and the starter relay. This stopped the headlights from dimming when at idle.

I told you all that to tell you this. I have a 1976 vintage, 78 amps, two fields, externally regulated alternator that looks almost identical to the stock 68 unit, at least from the front. I am thinking about installing this unit if the unit I ordered will not carry the load.

I could convert the wiring and change out the voltage regulator to support a two field alternator and will if all else fails. For the reasons stated I'm considering trying something different. I've heard but have been unable to confirm that if one of the field wire connections of a 1970's vintage alternator (like the one I have) is shorted to the alternator case that the unit will work with the old style (1968) voltage regulator as a single field unit.

Is this true? If it is true, what is the estimated output amperage?

[Charger RT]

yes you can just wire the one field wire to the case or any ground for that matter and you will then have a 1 field wire alternator and it will work just fine with the 69 and back regulator. The alternator on my 68 is that way. Its output should be what ever it was rated. grounding the field won't change that. I believe you said the wiring has been upgraded already? if not the alternator will be a little too much for the OEM battery wire on the back of the alternator.
Tim

[Needa68]

Tim: This is excellent news! If the 60 amp unit I ordered doesn't carry the load I'll use one of the square back units. In fact, tomorrow I'll hook up the square back unit I have. I believe it's rated at 118 amps because it came off a 440 cid engine I took out of a 76 Winnabego RV. I had it tested today so I know its working properly. Thanks again for your reply.

RHM, Jr.

[Charger RT]

The only problem with juiced up alternators on these cars is the wiring was not designed for the higher amp alternators. (They really weren't designed for the OEM alternator either.) The amp meters either. I have a 60 amp on my 68 charger and when the car sits for a few months I have to watch my RPM for a little bit after starting it because it will pin the amp gauge or I have to charge the battery before starting it to avoid basicly using my full 60 amp alternator. It has burnt the alternator wire at the fire wall twice the first time with the low amp OEM alternator many years ago. When I repaired it the last time I ran a second wire from the alternator back to the battery. I saw the thread here where someone upgrades the wireing to the amp meter and it is a good idea but the amp meter is still the OEM it will still pin out at 60 amps. Good luck with your upgrade and check wire size.
Tim

[Nacho-RT74]

when you get an alt able to feed the car at idle without need to suck from batt, you won't see ANYMORE the ammeter spiking to full Charge because battery won't be EVER discharged due the low alternator capacity at iddle. Maybe just at certain moments but not quite firmly reading discharge, like on old stock setup.

My alt is 60 amps unit and I can't remmeber when it was the last time I saw my ammeter at full reading... just before the upgrade. I think the max load at ammeter I have had at Charge side is 1/2 of the way for 5 minutes or so, and I run A/C all day, everyday. True that barelly I set my A/C at max blower speed. Maybe just quite often at day, under the sun, but I'm not using the headlights at that moment, so not unnecesary extra load

[Charger RT]

when you get an alt able to feed the car at idle without need to suck from batt, you won't see ANYMORE the ammeter spiking to full Charge because battery won't be EVER discharged due the low alternator capacity at iddle. Maybe just at certain moments but not quite firmly reading discharge, like on old stock setup.

My alt is 60 amps unit and I can't remmeber when it was the last time I saw my ammeter at full reading... just before the upgrade. I think the max load at ammeter I have had at Charge side is 1/2 of the way for 5 minutes or so, and I run A/C all day, everyday. True that barelly I set my A/C at max blower speed. Maybe just quite often at day, under the sun, but I'm not using the headlights at that moment, so not unnecesary extra load

If you drive the car daily fine that all works. I have seen your thread on running 2 extra wires to the amp meter to correct wire size and it was done very nice and this should be done to any car running a stock amp alternator. But the problem still is the amp meter is a low amp unit. Most of our cars are no longer daily drivers and can sit for periods of time. When we get into them we want to start it and go. After a few weeks of sitting you would need to let the car idle for 15 to 30 minutes before the system won't spike the amp meter just rolling down the road or put the battery charger on the car before starting it even though the battery has plenty of power to start the engine. Spike the amp meter long enough and it will go open. Last thing one of these guys needs is that the amp meter fail at a car show a 100 miles from home. No car today uses an amp meter they have all switched to a volt meter. The only thing I have worked on latley that uses an amp meter is an ambulance but it uses a unit with a shunt but uses a volt meter to warn the operator the system is not working right and a volt reading to engage high idle to bring voltage up.The vendors that supply us parts either need to make us an amp meter that can handle the amps these higher amp alternators are putting out or design one that uses a shunt so that we can shorten the lenght of wire between the alternator and battery and of course it needs to bolt in and look OEM. Until then I will bypass it and run a correct size wire from the alternator to battery and hide a volt meter under the dash and let my amp meter look pretty in the dash doing nothing.

The other problem is we are adding new items to our cars that were not available 40 years ago. There is a headlight mod I found here to brighten up the headlights. We have been doing the same mod to newer dodges in the turbo forums. This mod hooks the head light load to the battery side of the amp meter. This alone now adds issues to the amp meter since the load has been moved to the other side of the amp meter. I would also power any electric fan right off the battery with relays. This too would be on the wrong side of the amp meter adding a constant reading on the amp meter.
Tim

[Nacho-RT74]

about the weak ammeter rate on stock cars... yes is true, and get a better unit with a shunt is better, but I can testify is not mandatory. Anyway on a car parked long time ago, allways is recomended, not by me, really by any professional, charge the batt with a home charger and not in the car. I make that advice/note on thread.

There are some websites around talking about shunts to ammeters.

Relay upgrades. One of the biggest mistakes is hook relays to batteries, because ammeter will read that ALLWAYS like a discharged batt, so power is allways running thorugh ammeter, so causing unnecesary heat there. The correct way is hook relays to the alt side, because THE ALT is what must feed the car as much as posible, and not the batt. More time power coming from alt to feed the car ( like is originally designed, thats the reason main splice is on alt side ), less power going through ammeter so less power being succjked from batt. That's why the parallel wires upgrades and more powerfull alt ( able to feed the car at idddle ) are hand by hand, and won't work separatelly.

The basic on this is when and why make some stuff on one or another way . Everything has a reason for it.

what burns everything on stock electrician design is:
-hooks everything on wrong side.
-not enough charge capacity at idle, so batt is being constantly sucked
-constant recharge reading with high readings due same reason when reving up ( thats why the first burn spot is allways the black wire at bulkhead )

[Charger RT]

about the weak ammeter rate on stock cars... yes is true, and get a better unit with a shunt is better, but I can testify is not mandatory. Anyway on a car parked long time ago, allways is recomended, not by me, really by any professional, charge the batt with a home charger and not in the car. I make that advice/note on thread.

There are some websites around talking about shunts to ammeters.

Relay upgrades. One of the biggest mistakes is hook relays to batteries, because ammeter will read that ALLWAYS like a discharged batt, so power is allways running thorugh ammeter, so causing unnecesary heat there. The correct way is hook relays to the alt side, because THE ALT is what must feed the car as much as posible, and not the batt. More time power coming from alt to feed the car ( like is originally designed, thats the reason main splice is on alt side ), less power going through ammeter so less power being succjked from batt. That's why the parallel wires upgrades and more powerfull alt ( able to feed the car at idddle ) are hand by hand, and won't work separatelly.

The basic on this is when and why make some stuff on one or another way . Everything has a reason for it.

what burns everything on stock electrician design is:
-hooks everything on wrong side.
-not enough charge capacity at idle, so batt is being constantly sucked
-constant recharge reading with high readings due same reason when reving up ( thats why the first burn spot is allways the black wire at bulkhead )

Obviously we disagree on how to upgrade these cars.

These cars had electrical issues 40 years ago when they were built. Today cars are built and wired very differantly. Today most cars are running a power distribution box under the hood powered by a large cable (larger then our stock alternator cables) to power most stuff right off the battery. This is how it should be done unless an Amp meter can be had to handle the max load it might see or one using a shunt not one that can only handle a portion of what is possible.

Your way is fine if everything works. What happens in your setup if the alternator fails while on the road. Power is being pulled back throught the amp meter if the car is stock with stock loads you will run until the battery voltage drops to a point the engine will not run. That would be fine but today we have added an aftermarket radio with maybe an amp to power some speakers, replaced the fan to cool the car with electric fans and we have no alternator to power it so the battery takes over with the amp meter getting hot. what happens when the amp meter quits because it is seeing an amp load higher then it was designed to see? no power no where. and a call for a tow truck.

By just scrapping the amp meter (just not using it. the added cable listed after this will just make it not work like before it will just sit there at the middle position) and running a large cable back to the battery to charge it and adding a hidden voltmeter or a volt meter you can see if you like. You can add the new toys with fused relays right off the battery and get home if the alternator quits on the road. This way the load is pulling at the battery and the switched power for these circuits can be saftly added to the igntion side of an under sized system without pulling even more amps from the system. In this way the alternator supplies the battery and all loads can be pulled from there. The battery also is the best filter you can get to smooth out any ripple the alternator might be producing.

Let agree to disagree.
Tim

[Nacho-RT74]

no prob just exposing my theory

and yes I never thought in case of alt fail, the amm will with ALL the load, thats definitelly true. But well, I think I forgott the last time my alt failed, just replaced bearings. Maybe keep the alt charging less as posible with the upgrade, just enough to feed what is working did help on keep low loads on all the system, including inside alt , and that helped on alternator lifetime with less heat on coils, coil leads, brushes and diodes

just a theory, thinking on how this alt has got this life without fail.


anyway, if alternator fail shouldn't you turn off as much as posible everything unnecesary to keep a good reserve charge working on the necessary stuff to keep riding ?

but you defintelly got a good point on the alt fail case.  never though on that before 

[Needa68]

Tim and Nacho: I've enjoyed your dialog! You guys may disagree on exactly what needs to be done but I think it's correct to say we all agree that whoever designed the electrical systems in our old MOPAR's missed the mark.

Here is an update on where I am with this bucket of worms. First some background:

1) I have not physically bypassed the amp meter but it does not work because of the Harness Preserver (HP) mod I installed a couple years ago.
2) As part the HP mod a voltmeter was installed. It's connected to a switched circuit and mounted under the dash near the ignition switch.
3) Also as part of the HP mod a heavy wire (maybe 8 AWG) was run between the alternator output terminal and the big terminal on the starter relay. This gave a path for the battery to charge without routing current through the firewall.
4) The HP mod was installed after a heater only to AC / heater system upgrade. When the AC system was activated the lights would dim. The HP mod helped alleviate this problem.
5) Per the instructions the AC blower motor was hooked to the old heater box power feed.
6) Power for the radiator fan comes from the alternator output terminal.
7) The circuit that engages the AC compressor clutch is also used to trip a relay that applies power from the alternator to the radiator fan.

Since I last posted here I've installed and tested three different alternators. I got the best results with a square back alternator (2 field terminals). As per Tim's suggestion I shorting one of the field terminals to the case and used the existing voltage regulator and ballast resistor. This arrangement handled the load better than either the original alternator or a new 60 amp unit. However, when the AC unit, radiator fan and all lights were switched on the voltage meter in the passenger cabin dipped to 10 volts. At the battery the voltage reading was 11.53 volts. This was at idle speed!

Given all I've read about the bulk head connector bottleneck I decided to run a dedicated circuit from the starter replay to the AC system. One could argue I should have used a relay to activate this circuit but I didn't for purposes of this test. I used an in line fuse. Power is now always present at the AC blower switch. The power is applied when the blower switch is activated.

By passing the bulkhead connector with a direct feed to the AC system blower motor improved the voltage reading at the voltmeter under full load from 10 to 10.8 volts and at the battery from 11.53 to 12.2 volts.

Next steps:
1)   Use the square back alternator for the time being.
2)   Leave the radiator fan hooked up. AC is running extra cold and engine is not over heating at idle like before.
3)   Install a carburetor solenoid to bump the idle speed when the AC is activated.
4)   Investigate viability and benefits of converting to a dual field charging system.
5)   Ask for other suggestions.

[Charger RT]

Tim and Nacho: I've enjoyed your dialog! You guys may disagree on exactly what needs to be done but I think it's correct to say we all agree that whoever designed the electrical systems in our old MOPAR's missed the mark.

Here is an update on where I am with this bucket of worms. First some background:

1) I have not physically bypassed the amp meter but it does not work because of the Harness Preserver (HP) mod I installed a couple years ago.
2) As part the HP mod a voltmeter was installed. It's connected to a switched circuit and mounted under the dash near the ignition switch.
3) Also as part of the HP mod a heavy wire (maybe 8 AWG) was run between the alternator output terminal and the big terminal on the starter relay. This gave a path for the battery to charge without routing current through the firewall.
4) The HP mod was installed after a heater only to AC / heater system upgrade. When the AC system was activated the lights would dim. The HP mod helped alleviate this problem.
5) Per the instructions the AC blower motor was hooked to the old heater box power feed.
6) Power for the radiator fan comes from the alternator output terminal.
7) The circuit that engages the AC compressor clutch is also used to trip a relay that applies power from the alternator to the radiator fan.

Since I last posted here I've installed and tested three different alternators. I got the best results with a square back alternator (2 field terminals). As per Tim's suggestion I shorting one of the field terminals to the case and used the existing voltage regulator and ballast resistor. This arrangement handled the load better than either the original alternator or a new 60 amp unit. However, when the AC unit, radiator fan and all lights were switched on the voltage meter in the passenger cabin dipped to 10 volts. At the battery the voltage reading was 11.53 volts. This was at idle speed!

Given all I've read about the bulk head connector bottleneck I decided to run a dedicated circuit from the starter replay to the AC system. One could argue I should have used a relay to activate this circuit but I didn't for purposes of this test. I used an in line fuse. Power is now always present at the AC blower switch. The power is applied when the blower switch is activated.

By passing the bulkhead connector with a direct feed to the AC system blower motor improved the voltage reading at the voltmeter under full load from 10 to 10.8 volts and at the battery from 11.53 to 12.2 volts.

Next steps:
1)   Use the square back alternator for the time being.
2)   Leave the radiator fan hooked up. AC is running extra cold and engine is not over heating at idle like before.
3)   Install a carburetor solenoid to bump the idle speed when the AC is activated.
4)   Investigate viability and benefits of converting to a dual field charging system.
5)   Ask for other suggestions.

Sounds like you have been busy.

It sounds like with the add on A/C and electric fans factory looks are not that important to you correct?

I my self would just run all add on loads from the battery.(move the ones at the alternator to battery)  I would increase the wire size you have running from the alternator to the starter relay . I would also take it right to the battery instead of the starter relay.

I like to run 4 gauge wires from the alternator to the battery. What is your voltage at the battery and at the alternator terminal? Make sure the negative battery cable is not adding to the voltage drop.

technically a vehicle is not considered charging until the voltage is 1 volt above battery voltage (new thinking) so if battery voltage of a fully charged battery is about 12.55 we need to get your system up alot. What voltage does it do with the engine rpm up? What size pully is on the front of the alternator? What rpm does the engine idle at?

Do you know how many amps your A/C system (clutch and blower motor) draw? How about those fans?

I came across this link in a thread on this site and really thought it was written well and liked the way they added extra load carring wires inside the vehicle. It does bypass the amp meter and will help with voltage inside the car and getting the charge back to the battery. The only thing I would bo it run the charge wire right to the battery http://www.madelectrical.com/electricaltech/amp-gauges.shtml

On the voltage regulator do you still have the mechanical point regulator or has it been switched to an electronic version? My wife works at Advance auto and a few years ago found they stocked an electronic version of the old mechanical regulator. It works much better at maintaning a decent voltage at idle then the old mechanical ones.

But changing to the 70's and newer regulator isn't hard either. You just need to take your 2 exixting regulator wires off the regulator and tie them together and add one more wire to it. That wire goes to one of the terminals of the new regulator (yes it does matter which one) then run a new wire from the other terminal on the 70+ regulator to the field wire you grounded at the alternator.
The easiest way I can explain which wire goes where is if you look at the regulator plug and think of it looking like bouling pins from above. The wire you tied onto the old regulator wires goes to the 1 pin and the new wire you run to the alternator goes to the 7 pin. If I remember right 1 pin should have a blue wire and 7 pin green.
Tim

[Nacho-RT74]

well all my "discusion"  on this kind of threads is because I like the ammeter still working on dash and not just get it there like an ornament. They can work GREAT but of course taking care of some stuff.

( fortunatelly on this case it was REALLY A FRIENDLY DIALOG, on some case ppl treat me like I don't know what I say so I get angry and becomes on a hard discussion )

Then about the MADelectrical stuff... I'm TOTALLY disagree on one stuff they say, They say the main splice is being relocated to outside the cab with the modification what is TOTALLY FALSE. The main splice will be ALLWAYS inside the cab and that is imposible to change unless you made more heavy modifications. So do what you want bypassing ammeter and running alt source to starter relay, all the demand is driven INSIDE the cab, no matter where comes the juice, batt or alt. So once the "main splice" at starter relay as they call gets the power no matter from where comes, ALLWAYS is sucked to inside the cab and will find THE REAL MAIN SPLICE. However they are right and I'm agree about the weak points they are saving with the wiring job ( not really with the ammeter bypass though, even could help ).

that MADelectrical modification makes the main splice at starter relay deal being true, JUST IF you fit relays all around at engine bay like usually is being done when attaching at battery. In that case, the ammeter bypass is converted on some logical, but that doesn't makes the relays at battery a correct way with ammeters.

as stated, the ammeter even is true COULD IT BE A PROBLEM, not necesarilly it is if you carry the propper alternator. Less power going thru ammeter, less power causing problems, and that why a propper alternator comes to play TO FEED THE MAIN SPLICE before ammeter, when power never will come from batt, unles at certain moments so never will get the ammeter. EXCEPT like TIM said, if alt comes bad and then batt comes to play as only one piece to feed.

What Tim read and talked about some upgrades around, Is what I exposed here:
http://www.dodgecharger.com/forum/index.php/topic,33574.0.html


at the end everybody its at their own and choose the way, depending on how you want your car working. Both ways works and are effective BUT, I guess My deal is the correct use and language of the technical parts and fight with the missinformation

As far you know what you are making, you'll be fine, and what has been wrong allong the years is fit relays at batt with ammeters on the line making think the bad stuff was REALLY the ammeter, what it is wrong, the bad deal was the incorrect procedure all around. Is like upgrade a camshaft without taking care if the torque converter is matched with. Any change needs to think if the rest of the system is matched to the mod.

Another bad deal was upgrade cars with higher amperage batts but keeping small amp alternators what made get more time the high loads through the original system to charge back the batt. Is better to use same stock low amperage batts with higher amps alts OR both being upgraded at the same time.

But changing to the 70's and newer regulator isn't hard either. You just need to take your 2 exixting regulator wires off the regulator and tie them together and add one more wire to it. That wire goes to one of the terminals of the new regulator (yes it does matter which one) then run a new wire from the other terminal on the 70+ regulator to the field wire you grounded at the alternator.
The easiest way I can explain which wire goes where is if you look at the regulator plug and think of it looking like bouling pins from above. The wire you tied onto the old regulator wires goes to the 1 pin and the new wire you run to the alternator goes to the 7 pin. If I remember right 1 pin should have a blue wire and 7 pin green.
Tim

well I would run the new wire BEING BLUE splicing into the blue existing wire and in to the blue wire at new reg pigtail to keep the existing green wire in to the green wire at pigtail... just for keep mopar color codes and matching wires from end to end.

[Nacho-RT74]

Tim and Nacho: I've enjoyed your dialog! You guys may disagree on exactly what needs to be done but I think it's correct to say we all agree that whoever designed the electrical systems in our old MOPAR's missed the mark.

Here is an update on where I am with this bucket of worms. First some background:

1) I have not physically bypassed the amp meter but it does not work because of the Harness Preserver (HP) mod I installed a couple years ago.
2) As part the HP mod a voltmeter was installed. It's connected to a switched circuit and mounted under the dash near the ignition switch.
3) Also as part of the HP mod a heavy wire (maybe 8 AWG) was run between the alternator output terminal and the big terminal on the starter relay. This gave a path for the battery to charge without routing current through the firewall.
4) The HP mod was installed after a heater only to AC / heater system upgrade. When the AC system was activated the lights would dim. The HP mod helped alleviate this problem.
5) Per the instructions the AC blower motor was hooked to the old heater box power feed.
6) Power for the radiator fan comes from the alternator output terminal.
7) The circuit that engages the AC compressor clutch is also used to trip a relay that applies power from the alternator to the radiator fan.

Since I last posted here I've installed and tested three different alternators. I got the best results with a square back alternator (2 field terminals). As per Tim's suggestion I shorting one of the field terminals to the case and used the existing voltage regulator and ballast resistor. This arrangement handled the load better than either the original alternator or a new 60 amp unit. However, when the AC unit, radiator fan and all lights were switched on the voltage meter in the passenger cabin dipped to 10 volts. At the battery the voltage reading was 11.53 volts. This was at idle speed!

as stated, if you have a good charge at idde everything will be perfect, the deal is IT IS REALLY CHARGING/FEEDING AT IDDLE ?. With the alt I am using Is hard to notice if I have some dimming lights, like on old alts.

I used relays for every blower speed, before speed resistor.

[Charger RT]

Nacho I really like that drawing of the conversion. Fuuny thing is any newer mopar uses 2 green wires at the alternator for the field. I was looking at an 87 daytona diagram yesterday to help a guy on the FWD turbo forum I go to and the wire color starts out blue for the 12v+ feed to the alternator it stays blue and goes to the power module but at the slice it has to take the power to the alternator is changes to green.

The nice thing about the conversion to disconnect the amp meter is:
1 it doubles the wire size suppling all loads inside the car.
2 it shortens the lenght of the wire going from alternator to battery.

If detroit were to build this car today using an amp meter the wire size they would use from the alternator to amp meter and back to the starter relay would be hugh compared to what was used. I'm on vacation this week but next week I will grab my chart from my tool box. It shows wire size needed for a certain amp load and how long the run is. The run from battery to amp meter to starter relay is way to long for this gauge wire.

Now back to this posters issues. The added components on this car are electric radiator cooling fans, A/C compressor clutch, and a blower motor. The added amp load to this car is probably a little more then the OEM alternator would have put out. I believe with these mods and what he has already done to this car they should be powered more like a newer car. I myself would consider getting a power distribution box from a newer car and wire it up inder the hood to power these loads outside. That being a large cable (battery cable size) powering the box and the loads run off relays in the box. The current needed to trip they relays is low so any circuit needed to turn them on would not overload the inside circuits plus large cables would not be needed to be run inside the car then back out to where most of the load is.

With these loads I would think he would need at least a 100 amp alternator. My mini van with A/C a blower motor and 2 speed fan for the radiator came equipt with a 120 amp alternator. It covers the load correctly. A friend has a van equipt similar to mine had a previous owner replace the 120 with a 90. It just would not cut it. Adding this size alternator to this car with this size alternator wire with how long the factory made that run would be foolish. Without my chart I would have to guess wire size but 4 gauge battery cables can be had easy at any of the local parts stores. I would also run it straight across the front of the engine and hang it right off the front of the passenger side valve cover to the battery to keep the wire as short as possible. With his current set up I am willing to bet he has way to much voltage drop from the alternator to battery

Well gotta make dinner (steak) the wife just got home from getting the kids we spent the day at the shore and the kids were in a differant van on the way home.
Tim

[Nacho-RT74]

Nacho I really like that drawing of the conversion. Fuuny thing is any newer mopar uses 2 green wires at the alternator for the field. I was looking at an 87 daytona diagram yesterday to help a guy on the FWD turbo forum I go to and the wire color starts out blue for the 12v+ feed to the alternator it stays blue and goes to the power module but at the slice it has to take the power to the alternator is changes to green.

didn't know newer mopars got those wires changed the color... Pigtails to upgrade the old systems ( or replace the original one ) still gets blue and green



some other plugs I have seen locally down here are red and green though... and well, diagrams from 70s are green and blue, so I say that just to keep it match them correctly aged.

diagram I posted is just an edited version of one already existing around, adding colors and some more info.

The nice thing about the conversion to disconnect the amp meter is:
1 it doubles the wire size suppling all loads inside the car.

yeah, at the end is the same than the parallel wires in certain way

If detroit were to build this car today using an amp meter the wire size they would use from the alternator to amp meter and back to the starter relay would be hugh compared to what was used. I'm on vacation this week but next week I will grab my chart from my tool box. It shows wire size needed for a certain amp load and how long the run is. The run from battery to amp meter to starter relay is way to long for this gauge wire.

something like this ? (Scroll down up to 1/4 of page from top ):
http://www.allpar.com/history/mopar/electrical.html

will be interesting get it an expanded chart including the power loss by lenght. I know there are charts around though.

...

The added components on this car are electric radiator cooling fans, A/C compressor clutch, and a blower motor. The added amp load to this car is probably a little more then the OEM alternator would have put out. I believe with these mods and what he has already done to this car they should be powered more like a newer car. I myself would consider getting a power distribution box from a newer car and wire it up inder the hood to power these loads outside.

...

With these loads I would think he would need at least a 100 amp alternator.

DEFINITELLY AGREE!!!, even I think something in 80-100 rate, cause for example even using A/C and upgraded headlights, you barelly will use A/C blower at max speeds at nights, but 100 amps alt will give you more headroom, and less power consumption from batt at certain points, saving the ammeter step ( if decided to keep ).

To me, what I'm somekind of purist bummer LOL 80 will be nice, being I don't think to add extra fans, or stuf like that. I would be PLENTY HAPPY with 80 amps alt in stock form ( maybe some inner parts upgrade kit what I know are available )

For example Even I added 6 relays on my car everyone hooked to the ammeter stud ( once wiring upgraded ) the max relays closed working will be 3 ( headlights low or high, low speed A/C and some diff blower speed selected ), but that doens't mean 3 working at same load. Thats because on 3rd gens at least when you turn on the A/C, the low speed is turned on by default no matter what speed you set. If I set FAST, the load will run by the direct source ( ohm's law ) even low speed relay will be closed by the default setup.

[Needa68]

Tim and Nacho:

Here I will try to respond to Tim's earlier post. If is Tim's comment then my reply.

Sounds like you have been busy.

Reply: Yes! I hate having issues I can't resolve.


It sounds like with the add on A/C and electric fans factory looks are not that important to you correct?

Reply: I'm about an 80 % purest. The car came with factory air but instead of trying to restore the old system I chose to install one of the Perfect Fit Systems for 68-70 b-bodies from Classic Auto Air.

I've put off installing an electric fan as long as I could. In retrospect I probably should have installed a less power hungry unit but I needed the added cooling. The 440 engine in my original car ran hot (back in the day) but this one runs hotter. It's been bored out and beefed up some. I'll attempt to attach a picture of the engine compartment. I think you'll find it looks 80 % stock. I'll attempt to attach a picture of the engine compartment.


I my self would just run all add on loads from the battery.(move the ones at the alternator to battery)  I would increase the wire size you have running from the alternator to the starter relay . I would also take it right to the battery instead of the starter relay.

Reply: As configured it doesn't appear the loss due to impedance is that great. The wire between the alternator and the starter relay is heavier gauge than I originally thought. Also, please read later comment about voltage reading taken at battery and alternator. 


I like to run 4 gauge wires from the alternator to the battery. What is your voltage at the battery and at the alternator terminal?

Reply: The voltage readings between the battery terminals and between the alternators out put and ground in every test scenario was within .1 volts of each other. This leads me to believe the wire I installed between the alternator, starter relay and battery is close to being optimized.


Make sure the negative battery cable is not adding to the voltage drop.

Reply: Good point! I made sure all my grounds were in place and serviceable. I even grounded the alternator in one scenario but it made no difference I could discern. I used a bolt on the radiator frame as ground when taking the alternator output terminal readings. I believe that says my ground points are good.


Technically a vehicle is not considered charging until the voltage is 1 volt above battery voltage (new thinking) so if battery voltage of a fully charged battery is about 12.55 we need to get your system up alot.

Reply: My battery tested 12.65 volts for three days in a row.


What voltage does it do with the engine rpm up?

Reply: With no load the readings ranged between 13.7 and 14.0.


What size pully is on the front of the alternator?

Reply: Today I reinstalled the square back alternator with one field wire shorted to ground. Before I installed it I changed the two belt pulley. I downsized it from one that was 3 inches across to one that is 2 ¾ inches across.


What rpm does the engine idle at?

Reply: I don't have a way to measure rpm's. However, after installing the smaller pulley I was able to reduce the idle speed and still get readings in the 13.7 to 14.0 range at the battery under no load conditions.


Do you know how many amps your A/C system (clutch and blower motor) draw? How about those fans?

Reply: I know the AC draws less than 10 amps (on low blower) but more on high blower. I know because it blew a 10 amp fuse when I switched to high blower. It now has a 25 amp fuse installed. It was originally connected to the AC 30 amp fuse in the fuse box. The radiator fan also has a 25 amp fuse.


I came across this link in a thread on this site and really thought it was written well and liked the way they added extra load carring wires inside the vehicle. It does bypass the amp meter and will help with voltage inside the car and getting the charge back to the battery. The only thing I would bo it run the charge wire right to the battery http://www.madelectrical.com/electricaltech/amp-gauges.shtml

Reply: I haven't had time to look at this reference but will.


On the voltage regulator do you still have the mechanical point regulator or has it been switched to an electronic version? My wife works at Advance auto and a few years ago found they stocked an electronic version of the old mechanical regulator. It works much better at maintaining a decent voltage at idle then the old mechanical ones.

Reply: I'm using a heavy duty mechanical point regulator. I'll look into converting to the newer electronic one.


But changing to the 70's and newer regulator isn't hard either. You just need to take your 2 exixting regulator wires off the regulator and tie them together and add one more wire to it. That wire goes to one of the terminals of the new regulator (yes it does matter which one) then run a new wire from the other terminal on the 70+ regulator to the field wire you grounded at the alternator.
The easiest way I can explain which wire goes where is if you look at the regulator plug and think of it looking like bouling pins from above. The wire you tied onto the old regulator wires goes to the 1 pin and the new wire you run to the alternator goes to the 7 pin. If I remember right 1 pin should have a blue wire and 7 pin green

Reply: I saw Nacho's diagram concerning this change. It seems straight forward enough, even for me.

The pulley change I made today made a world of difference. In fact, I was concerned the system might be over charging the battery but it never went above 14 volts or below 13.5 volts between the battery terminals the whole time I was monitoring it.

With all systems on and the engine at idle the voltage readings between the battery terminals is in the 12.1 – 12.3 range. The meter in the passenger cabin reads about 11.8 but that could be a function the meter because it is not a precision instrument, if you know what I mean.

I'm going to run it like this for awhile and continue to monitor its performance. Many thanks to you and Nacho for responding to my call for help.

[Charger RT]

nice under hood shot. I wish mine was that clean. (still has 41 year old paint on it) I would like to see a picture of the whole car.

The A/C does look nice and clean. With the modern compressor under the hood you should consider converting the alternator to the newer denso unit so many new dodges use. The link Nacho posted mentioned it. I have thought about it but never had time to match things up. That link said it can be done. (I might look more into it) One of those alternators can be had cheap used. They were on most mopars from the last 80's to probably now or close to it. They are very reliable and run for ever. The wiring hook up is the same as what you have on there now. They come in 90 amp (4 7/8" diameter) and 120 amp (5 3/8" diameter) The only thing that really goes wrong with them is after 125,000 to 150,000 miles the brushes wear out. imagine that. Brushes are about 10 bucks and easy to install the tin cover on the back just needs removed to replace them no splitting the case link so many other alternators need and its ready for another 100,000 miles. A V belt pully might be the hardest part. I was just looking on ebat there are denso applications that use a v belt pully so I am sure a pulley can be found. This has me thinking. By the end of the year I may have a denso on my charger. Nacho this might be your answer for more amps too.

Are you running a pusher fan or puller? I see the shroud there and was wondering. Mine has always run a little hotter then I like and have considered an electric fan but I sorta am a purist. I have run an extra charge wire but it is black and tucked under the main harness out of site. I currently have a fan blade from a late 60's B body with A/C on the car it has a little more pitch then the 440 non air blades.
Tim

[Needa68]

The picture was taken awhile back (when AC was installed). It looks better now than then. The radiator / condensor fan is mount in front of both and is pushing air into the engine compartment. Even though it required me to make mounting special brackets there is room for it on the passenger side.

I suspect the fan being mounted in front of the radiator has you wondering how it was done. What I didn't mention is that I drive a 68 Coronet. The car pictured next to our DodgeCharger.com forum ID (Needa68) is the car I'm restoring for my son. As a result of my experiences with electrical issues you can bet it will have a modified electrical system. The sad part is I've aready gone through all the Charger's wiring to include installing a new bulk head connector and repairing all mods made by the previous owner. It looks like I get to revisit the dash and engine compartment wiring harnesses. I was gearing up to put on a vinyl roof and install a headliner in the Charger before I started the Coronet's radiator fan mod which led to all the electrical issues.

Given all the new data I've gathered I will probably also revist the Charger's instrument panel which of course I've already refurbished and reinstalled in the restored dash. I'm now thinking I'll have the amp meter converted to a volt meter.

It's been awhile since I updated our Charger blog but if interested you can take a look here.  www.geocities.com/robertmitchell32000

RHM,Jr.

[Charger RT]

That link is great. The car looks great. I will have to go back and look some more later when I get time.
Thanks
Tim