Increased Alternator Output at Idle - Opinions

[68neverlate]

Hey guys... thought I'd put this out there for feedback.  I'm interested in what you have to say...

I've been operating my '68 Charger over the past few months with the aid of a battery charger.  On a fully charged battery, I would get about 4 - 6 hours running time so long as I didn't use any power other than what the ignition wanted (no radio, headlights, blower etc).  When the battery got low, I'd recharge with a battery charger and be good for another 4 - 6 hours.  When the car was running, I observed that the ammeter never showed a charge condition on the battery, it was always in a discharge state.  With nothing else on, the needle would be just off the discharge side of centre.  With headlights on, the needle would show halfway between centre and the full left discharge position.   

I suspected a bad alternator, but replaced the voltage regulator first to ensure that was not the issue.  I confirmed it wasn't.  I took the alternator out of the car and into a local auto parts store to have it bench tested and found that it was only producing 4.7 volts.  I took it home and cracked it open to see if I could further diagnose the problem.  It turns out that it was missing one of the brushes... it's amazing it was producing any power at all (all the was touching the contact point on the rotor was the end of the small spring under the brush)!  I took it into an auto electric shop and got a quote on getting new brushes. 

So, that's the background, and here's the issue.  While I'm getting the alternator fixed, I thought I'd also address the low-output-at-idle issue that exists with our cars.  My existing alternator already has a smaller than original diameter double pulley.  That'll help somewhat.  When I discussed this with the techs at the auto electric shop they suggested a variable voltage regulator so that the field voltage can be bumped up to 14.7 - 14.9 volts to compensate.  I asked if this would compromise any wiring when at full throttle and they said it would not.     

I've read a lot of threads on this subject and know there are other ways to address the low-output-at-idle issue.  Regardless of which option I choose, I also plan on bypassing the bulkhead connector by running a 10g wire straight from the alternator to the splice under the dash.  I'm also replacing the fusible link (the techs indicated that the correct size fusible link for me would be a 14g wire... if someone could confirm that, it would be nice) to ensure I have proper protection for my wires in place. 

The wiring in my car was all replaced in a restore that was done by a previous owner some 10 years ago, so it's in pretty good shape.  It is all stock, no mods or any after market add-ons.  The car is original and I'd like to keep it that way (ie: no AC Delco alternators etc.).  My ammeter works and I'd like to keep it that way (I've read some threads suggesting a modification to bypass the ammeter).  I do have factory air on the car, but it is currently disconnected (no doubt because of the charging issue).  I would like to re-connect this at some point and get it working one day as well.   

Given the info above, and taking into account the other modifications suggested to resolve low-output-at-idle and reduce/eliminate fire hazard issues that result from large currents going through the bulkhead connector and ammeter, would you agree that the variable voltage regulator option is a good way to go?

I really appreciate hearing what you guys think.

Cheers,      

[flyinlow]

I run a Jegs 100 amp chrome single wire alternator with an internal regulator. Yea it's a chevy alt. I don't care who makes my electricity and this thing makes a bunch of it, even at idle. Got one on the El Camino. Between my Buddy's and me we have eight of them on our old cars. We even bought a spare when it was on sale for$105. When someone goes on a longer road trip they throw it in the trunk. I do have to take a little grief from them occasionally,being chevy guys.

[68neverlate]

Thanks for your reply flyinlow... I've heard this is one of the best ways to resolve the issue, but I'd really like to stick with a Mopar solution if at all possible.      Just out of curiousity, did you change any of the wiring from the alternator to the splice when you put the higher capacity alternator in?

Looking forward to hearing from the rest of you guys on other options and what you think of the suggestion I got from the techs I talked to...

Thanks for your interest!      

   

[Cooter]

Think Delco made the HUGE "Police" and HD alt. in the Mopar vehicles, so i wouldn't worry too much bout the GM one. Yep, Just simply swap in a Delco 1 Wire and charging woes be gone...Watch all your buddies bitch about idle charging problems then.

[flyinlow]

Yes I upgraded the alternator wire to # 6 or # 8 and put a 100 amp fuse on the wire. I have a trunk mounted battery. I installed a charging post near where the battery had been. This is the central point of my electrical system now. I took the ammeter out of system before I put the 100 amp in.
.
Some guys are using the Denso 120 alt.kit from Mancini. Was used on Mopars in the 90's and it looks like a small Mopar alt.

[Chryco Psycho]

Denso is the solution I was going to suggest but put a bypass 8 or 10 ga wire from the alt terminal to the stud on the starter relay so all the power doesn't go through the ammeter & firewall plug .
A smaller pulley on the factory alt will turn it faster also

[John_Kunkel]

I'd go with a Denso, lots of mounting brackets available and if you get a Powermaster it will come with an output/rpm tag.

[b5blue]

I use the Mancini Racing's 120 amp Denso "kit". Works like a charm on my 70, requires a 70 up type regulator, 60-80 amp output @ idle. Dodge is not wired exactly correct for a 1 wire alt. but it is doable and less money. I have zero mods electrically on my car and the Denso puts out so much juice you need the battery in good shape, fully charged as it goes to town charging that puppy back up. All of Nacho's upgrades are recommended under his: "Some considerations" topic. If it makes ya feel better that Denso was a "Dodge part" in the past and the included brackets and hardware are 1st class stuff. 

[Brass]

Tuff Stuff:

http://www.summitracing.com/parts/TFF-7509RESP/

I love mine.  But also run the ammeter bypass.

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

[flyinlow]

Tuff Stuff:

http://www.summitracing.com/parts/TFF-7509RESP/

I love mine.  But also run the ammeter bypass.

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

I like that alt. Thats the first time I have seen that. If I had not already made the upgrade to the Delco style I would consider it.  How long have you had it?

[Brass]

About 5 or 6 months.  So far, so good.

[John_Kunkel]

Tuff Stuff:

http://www.summitracing.com/parts/TFF-7509RESP/

Advertised as having an "internal" regulator..what's that bolted to the back that might not clear the head on some installations?

[68neverlate]

Appreciate the feedback guys... any comments on the techs' suggestion to bump the field voltage with a variable voltage regulator?  With factory wire routing?  with Nacho's mods?  Good... bad?

[Nacho-RT74]

I'm great and happy with "Nacho's Mod"
























































( actually is noy My mod, is just what MaMopar originally did on High output alts but refreshed and upgraded on our old and existing wiring )

[68neverlate]

As you should be!     

Regardless of whether it was "your" mod or not, I'm giving you the credit because, at minimum, you were the messenger!  Many great contributions to this site through your threads on electrical Nacho... I've read through and learned a lot from them.  Good stuff...     

Regardless of which direction I go with the alternator (MOPAR, Denso, or ... etc.), and whether I use the variable voltage regulator or not, I'll be making the modifications set out in your threads to avoid the overheating problems at the bulkhead connector and the ammeter.  I don't want to supply the fuel for a neighbourhood marshmellow roast because my wiring couldn't handle the load!         

[68neverlate]

I just talked with the tech at the local auto electric shop I've been dealing with and he explained that alternator output is determined when the alternator is at maximum RPM and that higher rated alternators actually have lower output at lower RPM because of the power "curve". 

They've recommended a lower rated alternator (60 amp) to rectify the low-output at idle problem. 

Does that sound right to you guys??     

   

[flyinlow]

I just talked with the tech at the local auto electric shop I've been dealing with and he explained that alternator output is determined when the alternator is at maximum RPM and that higher rated alternators actually have lower output at lower RPM because of the power "curve". 

They've recommended a lower rated alternator (60 amp) to rectify the low-output at idle problem. 

Does that sound right to you guys??     

   

NO

[Nacho-RT74]

+1

[flyinlow]

Any alternator has a rpm that it can produce its maximum amperage. Usually about cruise speed. At idle it will be lower and at very high rpms the alternator starts to self limit.  How much you get at idle depends on the idle speed, pulley sizes and the design of the alternator itself.
Showing a slight discharge at idle with a high electric load is not a problem with old Mopars. As soon as you start moving the rpms pickup and the alternator produces more electricity than the car demands , the ammeter shows charging, the battery is being slowly charged and life is good. Unless your Charger is a cop car or taxi you spend a lot more time driving than sitting at a traffic light, so the battery stays charged.

[flyinlow]

Trivia:

Chrysler was the first of the Big Three to switch from the generator to the alternator.

Alternators work better than gens. at low speed.

Alternator windings that get hot during power generation are in the housing, not the armature like a gen. ( you can see them on a Mopar alt.) this helps with heat dissipation.

Alternators self limit at high rpms ,so a stuck or bad regulator is not as big of a problem as it would be with a generator car.

Only the field current goes thru the brushes on an alternator, less maintenance.

[flyinlow]

Sorry,got off the point. Let me use an example. My 73 Charger. Came with a 60 amp electronic regulator system. Lets assume the alternator made 50% of its power at idle and 100% at 2000 engine rpm.

I start the car, slightly discharging the battery, the alternator starts recharging the battery                                                                10 amps
ignition                                                                                                                                                                           3 amps
I pop in a CD                                                                                                                                                                          5 amps?
I turn on the headlights                                                                                                                                                           20 amps
brakelights /backup lights as I back out of the garage                                                                                                                   10 amps
total so far                                                                                                                                                               48 amps
my stock alternator will be losing until I start driving down the road, 30 amps available at idle

Now I am going down the road, brake and BU lights off     10 amp load reduction   alt at rated rpm                                           38 amps  alt. winning
Lots of deer ,better use the high beams and turn the defroster on to clear the glass ( AC runs)                                                            20 amps
alt.just keeping up ,the battery is charged now  so that 10 amp load would reduce and the alternator would do a little better.

[flyinlow]

You can drive the car this way (we did for years). Now I add two cooling fans, 10.5 amps each and  trans. OD and lockup solonoids looking for power. The bigger alternator starts looking more attractive. It wins the power contest  more of the time. Modern alternators are rated higher and have to produce at a lower rpm with most cars using OD trans today.
I think you can get the original style alternators up to 75 amps ,which should work well unless you have added a lot of electrical demands. 

[b5blue]

  I spent many years sweating this "low idle amps" problem looking for a solution. Even waited for 8 months for Quick Start to develop their High Output Mopar Alt. with the extra windings stuffed in a stock case.     One wire Alt's looked to be an option but are not a good match for how Ma Mopar wired these cars from the factory, they are great on cars engineered for that type of charging system.
  I just finally gave up and bit the bullet and spent 250.00 for the 120 amp Denso Kit. What a change in the car! Yea you bet I make darn certain my battery is in great shape and fully charged as this thing throws out plenty of amps. I have my radio and cover plate out so I can reach in and feel how hot my Alternator gauge gets and have been checking it for about a year now to see how it does. When I've cranked the engine allot messing with stuff or let the thing sit for long periods and the battery is down the terminals do get pretty hot after 4-5 minutes of recharging. What I do (For now.) is shut it down for 10-15 minutes and it cools down. Then restart and run 5 minutes or so and if I still see if it is still feeding the battery I let it rest again. I only had to do this a few times during my intermittent crank but no start days (Due to an unknown bad splice in my engine harness at the time.) Other than this mod my 70 Chargers harness is still stock everywhere, the car now runs all systems much much better, ignition, lights, wipers and blower motor all run much more efficiently not starved for current. I'll never go back to low/weak output again. All my battery does is crank the engine and supply power to light the ignition, then it's done, my car even starts faster as Alt output kicks in while cranking, reducing draw on the battery. 
I've bought the new reproduction Alternator gauge as it's rated at 60 amps not 40 like the originals and will be installing it this winter when I redo my gauges. (That should give me a greater margin of safety along with some control relay mods and putting a primary alt. output distribution terminal close to my Denso.)   

[flyinlow]

One problem with a big alt. is the factory ammeter. If you discharge your battery to the point of of barely starting or jumping it, then you big alt. starts sending 100 amps thru the factory ammeter to recharge the battery,you can have problems. If you developed a short that was not protected by a fuse, the alt. would try to feed it. The battery side is somewhat protected by a fusible link I (#14 ?) I run my alternator charging wire thru a 100 amp fuse to the starter relay.

I liked the ammeter gauge, but they are source of problems. I don't want to run 100 amps into the dash and back out if I don't have to.

The only wayI know to have 60 amps avialable at idle is to have a 100+ amp alternator.

[68neverlate]

Reading with interest guys... all great stuff.   

I follow your example flyinlow... and can see that just sticking a larger alternator into the picture without considering the wiring and the ammeter is not a good idea.        And I do see where a 60 amp alternator might have trouble keeping up, even if you don't have a lot of extras running.

I have a question though.  Given a situation where you have a high output alternator (100+amps) and the battery is in a serious discharged state, the car is cruising (alternator is at maximum output) and the draw on the alternator other than the battery recharge is minimal... wouldn't the fusible link on the battery side only allow so much current to go to the battery before blowing therefore protecting your factory 40 amp ammeter (assuming it's still wired as per factory and the fusible links blows before 40 amps are allowed to flow in the circuit)??  As I see it, the flow of electricity has to go from alternator to ammeter back out to starter relay (through the fusible link) then to battery in order to recharge the battery.  So, wouldn't the fusible link protect everything in the circuit starting at the splice all the way to the battery regardless of where the fusible link is in the path?   

[Nacho-RT74]

I liked the ammeter gauge, but they are source of problems. I don't want to run 100 amps into the dash and back out if I don't have to.

you are allways in danger to draw all the amps the batt is able to give untill wire, terminal or whatever around blows out on short.

if you have a thick wire will draw all the amps the wire is able to hold untill blow by what batt gives, no matter if you have a 40 60 or 100 amps ammeter gauge.

Note, the amps are given by what device requires... a short requires EVERYTHING from the source ( the batt ), except if the medium blows and cuts on that moment ( ie fuse link, thin wire, terminal etc... )

[flyinlow]

Reading with interest guys... all great stuff.    
I have a question though.  Given a situation where you have a high output alternator (100+amps) and the battery is in a serious discharged state, the car is cruising (alternator is at maximum output) and the draw on the alternator other than the battery recharge is minimal... wouldn't the fusible link on the battery side only allow so much current to go to the battery before blowing therefore protecting your factory 40 amp ammeter (assuming it's still wired as per factory and the fusible links blows before 40 amps are allowed to flow in the circuit)??  As I see it, the flow of electricity has to go from alternator to ammeter back out to starter relay (through the fusible link) then to battery in order to recharge the battery.  So, wouldn't the fusible link protect everything in the circuit starting at the splice all the way to the battery regardless of where the fusible link is in the path?    


[/quote




Yes the link would protect the battery from receiving a large current. however...all of that current would be going back thru a small charging wire (#12?) from the alternator ,thru the bulkhead connector twice and the factory alt. gauge before getting to the fusible link right before the starter relay.From the starter relay to the battery is a short distance in a much larger cable. Each of those earlier mentioned items is a Resistance to the 100 amps trying to go where 40-50 was meant to. What will give up first?
You can probably get away with this a few times, but it will eventually catch up to you.

[68neverlate]

Yes the link would protect the battery from receiving a large current. however...all of that current would be going back thru a small charging wire (#12?) from the alternator ,thru the bulkhead connector twice and the factory alt. gauge before getting to the fusible link right before the starter relay.From the starter relay to the battery is a short distance in a much larger cable. Each of those earlier mentioned items is a Resistance to the 100 amps trying to go where 40-50 was meant to. What will give up first?
You can probably get away with this a few times, but it will eventually catch up to you.

OK, I follow you... so what would you think of this then. 

I replace my stock alternator with a rebuilt 70 amp Mopar alternator having the smaller diameter pulley to assist low output at idle.  I know it probably won't keep up to demands at idle, but it should be better than the factory set up.  I run a new #10 wire from the alternator straight through the bulkhead, bypassing the bulkhead connector to the splice and then continue with that #10 on to the one side of my factory ammeter.  From the other end of the ammeter, I also run #10 wire through the bulkhead (again bypassing the bulkhead connector) to the fusible link (#14) and from there to the contact point on the starter relay.  In conjunction with this, I also run a #6 wire directly from the alternator to the same connection on the starter relay.  On this wire, I have a #10 fusible link and a diode restricting the flow of current to one direction only (alternator to battery).
 
Would you agree that the increased wiring capacity should reduce wire resistance issues and the bypass going directly from the alternator to the battery starter relay should take at least half the load off of the current going through the ammeter circuit.  The decrease in current going through the ammeter will affect the degree that the ammeter needle moves, but it should still deflect somewhat, showing what state your system is in (charge or discharge).  If the #10 fusible link blows on the bypass from alternator to starter relay, then all the current needed to recharge a seriously discharged battery will go through the ammeter again.  Because of the #14 fusible link, that circuit would never see 40 amps before blowing the #14 fusible link, thereby protecting the ammeter.  That's only if the #10 fusible link blows in the first place, which is unlikely given that it should be able to handle the maximum output of the alternator even if the battery is taking everything the alternator can put out.   

What do you think??

[Nacho-RT74]

These are my thoughts

In conjunction with this, I also run a #6 wire directly from the alternator to the same connection on the starter relay.  On this wire, I have a #10 fusible link and a diode restricting the flow of current to one direction only (alternator to battery).

this is bypassing the ammeter... and no reason for a diode. Both together will make weird readings at ammeter.

Would you agree that the increased wiring capacity should reduce wire resistance issues and the bypass going directly from the alternator to the battery starter relay should take at least half the load off of the current going through the ammeter circuit.  The decrease in current going through the ammeter will affect the degree that the ammeter needle moves, but it should still deflect somewhat, showing what state your system is in (charge or discharge).  If the #10 fusible link blows on the bypass from alternator to starter relay, then all the current needed to recharge a seriously discharged battery will go through the ammeter again.  Because of the #14 fusible link, that circuit would never see 40 amps before blowing the #14 fusible link, thereby protecting the ammeter.  That's only if the #10 fusible link blows in the first place, which is unlikely given that it should be able to handle the maximum output of the alternator even if the battery is taking everything the alternator can put out.   

What do you think??

as stated will affect ( if not totally neutralizes ) the ammeter reading.

Fuse link will start to blow mostly at the time being being of course the smaller the first to blow totally. I would ever use a 10 gauge fuse link. 16 or 14 MAX. If two fuse links being used, 16 MAX. SHORT WILL BE FEED BY BOTH WIRES at the same time, so will be like you have 14 gauge or even 12 fuse link in total. If you fit a 10 fuse link, plus 14, will be ALLMOST like a 8 fuse link... will take FOREVER to blown and damage will be even worst


one question... are you eliminating the stock wires from alt and bat going through the bulkhead ? or still using them ?

[flyinlow]

The #6 wire from the alt. to starter relay/w #10 link/ diode.....hmmm...
The wire is fine. The link is better than no protection, I used a fuse. The diode, I am not sure about . The problem is most diodes have a 0.7 - 1.0 volt drop across them forward bias. At least the smaller ones do. So which way would the power go? The voltage at the Dodie output might be up to a volt lower then what went thru the alt. gauge?

The problem with dual path wiring is this. If one of your two smaller wires breaks ,giving you an open in the wire ,you would not know it until the system was flowing a high amperage load. At that point the too small wire would get hot.

I think the way you talked about would show normal discharge readings,but only partial charge readings?  If I understand what you are thinking of doing.

[68neverlate]

Hey Nacho... appreciate your interest and feedback on this.          

I was thinking about what I posted yesterday on my way home last night and had a few more thoughts myself, but first to answer your question.  Yes, I was planning on eliminating the stock wires from the alt through the bulkhead to the ammeter and back out the bulkhead to the starter relay and replacing that all with #10 (passing it both times directly through the bulkhead - not using the bulkhead connectors).

So my thoughts... after posting yesterday, I remembered that current takes the path of least resistance.  With my suggestion to run a #6 wire directly from the alt to the starter relay connection point, when a battery wants current to recharge, even though a second path from the alternator to the starter relay exists (the #10 wire I mentioned I'd be running above), I'm convinced that most, if not all, the current wanted by the battery will travel through the #6 wire.  The reason is that it is larger and shorter (and therefore will have less resistance) than the longer and smaller #10 wire making up the secondary route through the ammeter.  I initially thought that about half the current wanted by the battery would still go through the ammeter, but now I'm pretty sure it will be almost nothing, if anything at all.  So I can see what you're saying about the ammeter not getting much, if any, current. 

My second thought about the path of least resistance is that if there is a significant demand on the alternator from both the battery AND the car, (at idle let's say so the alt can't keep up to demand), because the path along the #6 wire to the battery is the path of least resistance (the path on the #10 wire to the splice and on through the fuse box and through to whatever device is asking for the power will have more resistance than the shorter #6 bypass wire), the battery will win the battle for power from the alternator.  If that happens, it means the car systems will not receiving much power from the alt and will have to get the rest from the battery.  So, in that situation (battery wants power to recharge and the alternator is not able to meet the total power demanded by the car AND the battery), effectively what my suggested mods have done is transferred more of the load of car systems from the alternator to the battery, which is the exact opposite of what I'm trying to accomplish.  Would you agree with that reasoning??   

I have another simpler idea that I have to put some polish to.  I'll post shortly...

Cheers,           

[68neverlate]

The #6 wire from the alt. to starter relay/w #10 link/ diode.....hmmm...
The wire is fine. The link is better than no protection, I used a fuse. The diode, I am not sure about . The problem is most diodes have a 0.7 - 1.0 volt drop across them forward bias. At least the smaller ones do. So which way would the power go? The voltage at the Dodie output might be up to a volt lower then what went thru the alt. gauge?

The problem with dual path wiring is this. If one of your two smaller wires breaks ,giving you an open in the wire ,you would not know it until the system was flowing a high amperage load. At that point the too small wire would get hot.

I think the way you talked about would show normal discharge readings,but only partial charge readings?  If I understand what you are thinking of doing.

Hmmm... didn't realize that there would be a voltage drop on the diode.  I think you're right about the ammeter readings (normal discharge and partial charge)... although if you follow my last post, it's possible that there could be nothing at all on the charge side.  And yeah, I agree that as soon as one of the parallel wiring circuits go and there's only one left, the current flowing through the remaining circuit could easily cook it if you don't account for it. 

I do have a simpler solution in mind that I'm putting some final touches to.  I'll post that tonight and see what you guys think of that. 

Thanks for your continued interest... really appreciate hearing you opinions!        

[flyinlow]

If you look at why electricity moves thru thru system, it goes from highest potential or voltage to the lowest.( I am not trying to argue which way the actual electrons move )  Alt makes 14 volt potential to ground. If you turn on a light or run the wipers you have 14 volts to push the current. A low battery( enough to still start the car) would be around 12.0 Only a 2 volt potential for the alt. to push current into the battery and reverse the discharge reaction. In this case you are probably OK. A total flat battery (car jump started) 0 volts,is where the alt. has its full 14 volts to  push high currents into the battery. Depends on the resistance of the battery.
If you had a big enough wire to  handle 100 amps and  a 100 amp ammeter (cop car?) and you ran heavier gauge wire every where it was needed you would probably be alright. For my car that's up to 1400 watts (heat gun) going thru the inside of my car, when it does not have to.  I know you want to stay stock looking, however Ma Mopar used relays under the hood to keep the high current of the starter motor out of the cab.   

[68neverlate]

That all makes sense flyinlow.  My objective is to limit the high currents in the cab as much as possible too (that's why I'm making the headlight circuit mods that John Kunkel suggested with relays), but also make it safe for when higher currents do pass through the cab due to a higher capacity alternator, excessive demand or a faulty charging system (dead battery or dead alternator).  I'm trying to accomplish this through fuses, upgraded wiring capacity and a parallel run.  And ideally, I'd like to do this with as little visual alteration as possible (stay with a stock alternator if at all possible). 

The more I get into this, the more I'm realizing that staying with a Mopar alternator may not be possible.  I'm going to see if the electrical shop I'm dealing with can build me a special Mopar alternator that looks stock but can produce 80 amps at max output as well as providing at least 40 amps at idle.  If they can, then I might be able to make the mods described below work.  So, this is the simpler solution I was talking about earlier today.  Interested to hear what you guys think.

Starting at the 80 amp alternator mentioned above, I use #8 wire to replace all the wiring from the alternator through the bulkhead (bypassing the bulkhead connector) to the splice to the ammeter and from the other side of the ammeter through the bulkhead (again bypassing the bulkhead connector) to a #14 fusible link with the other side of the fusible link connected to the contact point on the starter relay (basically, just upgrading the stock wiring to #8 and bypassing the bulkhead connector).  Now, for the parallel run.  Run a parallel #8 wire from the splice through a 30 amp fuse to the battery side of the ammeter.  One further modification... install another 30 amp fuse between the splice and the alternator side of the ammeter.  This should permit up to 60 amps (30 down each route) to flow from alternator to battery or battery to splice without blowing any fuses.

This mod should essentially half the current going through the ammeter circuit.  If the alternator makes 40 amps at idle and the car asks for 80 amps, the 40 amps shortfall will travel from the battery to the splice.  Because there are two routes for this power to get the the splice (ammeter route and the bypass), each would carry about 20 amps (wire size is the same on both).  Neither carries more than 30 amps, so the fuses are fine.  The 40 total amps should pass through the fusible link without blowing it, the car gets what it wants... the ammeter is receiving half of what it would otherwise, but it is still enough to cause the needle to deflect to the correct side, therefore telling you what state your charging system is in (charge or discharge).  It won't read the correct current, but it will tell you what state it is in. 

Now for the two extreme conditions, dead battery and dead alternator.  Assume the car asks for 80 amps and the alternator is completely dead.  All 80 amps will flow from the battery through the fusible link to the junction of the two parallel routes.  This time the battery is pushing 80 amps down the line.  If the fusible link does not blow on 80 amps, the #8 wiring will be fine because it is rated at much higher than 80 amps.  When the 80 amps arrives at the junction of the two parallel routes, it will half (40 amps) down each one.  Because the fuses are rated at 30 amps, they should both blow, protecting the ammeter.  If the battery is dead and the alternator is trying to push maximum current to the battery (assume car is asking for minimal power) then the same result occurs (both 30 amp fuses blow) protecting the ammeter.

Thoughts??      

[ChargerST]

I pictured it like this. It should work but it I'm not sure how accurate the ammeter would work as current would more likely flow through the bypass if the two lines don't have the same resistance (what's the internal resistance of the ammeter?).

Your mod is basically a fused shunt. in theory you can achieve the same result (although not fused) if you connect the two ammeter posts with a thin wire - it would take some load (like 10A) off of the ammeter.

[68neverlate]

Yup, that diagram pretty much puts a picture to my very wordy explanation last night!   

The only thing that I was picturing different is that I wouldn't be using the ammeter to connect to the battery side of the circuit with the bypass (trying to keep the current away from the ammeter to keep the heat down).  I'd be connecting a short distance away from the ammeter.

I follow what you're saying about the bypass taking more of the current because of the resistance of the ammeter.  It's important to ensure that each path takes half the current to maximize the efficiency of the bypass.  I think that's pretty simple to fix though... once the resistance of the ammeter is known, a resistor of the same value can be added to the bypass circuit.  With that change, each circuit would have the same resistance and, therefore, should carry the same amount of current.  I'm guessing the ammeter resistance would be quite low.

I have to give credit where credit is due... I looked back after writing this all out last night and noticed that my solution is very similar to the mod set out by Psycho Chryco earlier in the thread.  A slight variance on connection point of the battery side for the bypass and a few fuses is all that sets them apart.  And I'm sure if you look hard enough, other members have maybe made similar mods, so the idea isn't new.

Interested to hear if anyone knows the impedance of the factory ammeters so the correct resistor can be placed into the bypass circuit, although, I think I'd confirm my own ammeter reading to ensure the correct resistor size is selected. 

Thanks for the diagram ChargerST... I gotta get more savvy with the graphic part of this stuff so I can save a few keystrokes (and you guys some reading time)!           

Interested to hear from anyone else on any shortfalls/deficiencies that they can see of this latest mod...       

[68neverlate]

Apologies to Chryco Psycho... for ambi-dextering your name.  I can't even get my credits straight...    

[Nacho-RT74]

just one note... no matter what you do...all the power demand will go through the cab because the MAIN splice is inside the cab. There is not a way to change that unless a heavy mod or make a full relay setup all around. Being that the first and unvariable true, there is not something wrong on a heavy wire going into the cab.

once again, with a perfect iddle capacity of the alt you won't need ever to take care of the full alt capacity EXCEPT on a death batt, but since the alt you are getting you won't have ever a death batt, so don't worry about the full alt aoutput ever, trust me. I think you are overthinking this.

try first without the wire going to starter relay and if you are not satisfied, then go ahead with that extra wire, but I'm sure you'll be satisfied.

I kept the original wires simply for stock look, but I run 8 on alt side and 10 on batt side ( beside the stock ones still in use ) to the extras/parallel... I used those wires simply because a Coronet 76 I removed all the wiring had those and I reused for my car.

I call them PARALLEL just because I'm not removing the stock wires under the tape, but MaMopar didn't ever used those on the bulkhead bypass, and just used the ones through firewall even with 100 amps leece neville alts

[ChargerST]

I was thinking about adding an 8g or 6g wire from the the alt directly to the battery but switched with a heavy duty relay (100A). Then mount a small relay trigger switch inside the cabin. If I ever have a dead battery I just switch on the alt-battery connection to recharge the battery. That way there would be no current going through the ammeter. After the battery is charged I would switch off the connection and the ammeter would work again.

It would be even better if the relay would be switched on automatically by some sort of amperage sensing device (triggers the relay if it senses a certain amount of current at the + pole of the battery - starter motor shouldn't be a problem as it isn't used when the engine is running). A warning light could be added as well to tell the driver that the ammeter is not functioning momentarily as the battery is recharged. 

[68neverlate]

Thanks for the feedback Nacho... appreciate you keeping your hands (and brain  ) in this.   

I understand what you're saying with the power coming into the cab... I'm not really reducing anything because I'm increasing it (80 amp alternator compared to the original 46 amp) more than I'm reducing it (10 amps for headlights that will now come straight off the alternator with the headlight relay mod).  So, my main goal is to just make everything safe and still have the use of the ammeter to tell me the state of the charging system (it's not important to me to have an accurate reading on the ammeter, I just want to know what state it's in and if it's an extreme condition).  I think the mod stated should do that.

I got some news on the alternator front today... I talked to the head tech at the electrical shop and he was pretty confident he could build me a Mopar alternator that looks stock that meets the 80 amp max output and 40 amps at idle specs I gave him.  He said I wasn't on the hook for it if it didn't generate the minimum 40 amps at idle.       If he can't satisfy the specs, I'm probably going to have to break down and go with a different alternator.  Hopefully he comes through...

Now, I looks like I have a wiring project to get started on   ...

[flyinlow]

Looking at you diagram , I think your new ,larger direct routed wires will work. Still would leave the original fusible link near the starter terminal. If you ran a 75 or the 80amp Mopar alt. you are talking about and did have to jump start a flat battery, just let it idle for awhile before you hit the road. This is always a safer course with a low battery anyway. In case the engine stalls you are somewhere safe with the vehicle. After 15 minutes of so I would think you would be good to go. You could turn the headlights on if they where powered from the alt. directly reducing the power available to run thru the car to the battery. The best way is to recharge the battery before driving the car.  At work I can not take off if the the battery's are Charging at a high rate ,would have to wait until it drops or the better way and sometimes faster way is to have  maintenance swap in fresh battery's first. Don't want an overheated battery or thermal runaway in flight .
Good luck.

[68neverlate]

I was thinking about adding an 8g or 6g wire from the the alt directly to the battery but switched with a heavy duty relay (100A). Then mount a small relay trigger switch inside the cabin. If I ever have a dead battery I just switch on the alt-battery connection to recharge the battery. That way there would be no current going through the ammeter. After the battery is charged I would switch off the connection and the ammeter would work again.

It would be even better if the relay would be switched on automatically by some sort of amperage sensing device (triggers the relay if it senses a certain amount of current at the + pole of the battery - starter motor shouldn't be a problem as it isn't used when the engine is running). A warning light could be added as well to tell the driver that the ammeter is not functioning momentarily as the battery is recharged. 

This would be really cool (the detection of the low battery and automatic switching of the power)!  The direct link from alt to the battery is kind of where I was going in my first suggestion, however, I started having second thoughts about it when I thought it through a bit further.  I became concerned that I may be creating some further problems.  My first concern... the battery may win the battle for power over the car systems because there would be less resistance in the direct circuit from the alt to the battery than there would be from the alt to the systems in the car.  Second, if the systems in the car are not being satisfied by the alternator, it may attempt to draw the power from the battery.  It's even arguable that the new path provided via the direct bypass might have less resistance between the alt and the splice coming from the battery side of the ammeter than the factory path from alt to the splice.  If that's the case, you may be pushing all the power to car systems through the battery side of the ammeter, which may blow the fusible link, or worse yet, cook the wiring or the ammeter.     

I really like the idea of automatically detecting the low battery and having an automated switch to redirect power away from the ammeter and to the battery.  I'd just be concerned that it may create other problems while the battery is recharging.  I'm not sure these things are a concern or not, but it bothered me enough to rethink my original plans.  For what it's worth my friend...     

[68neverlate]

Looking at you diagram , I think your new ,larger direct routed wires will work. Still would leave the original fusible link near the starter terminal. If you ran a 75 or the 80amp Mopar alt. you are talking about and did have to jump start a flat battery, just let it idle for awhile before you hit the road. This is always a safer course with a low battery anyway. In case the engine stalls you are somewhere safe with the vehicle. After 15 minutes of so I would think you would be good to go. You could turn the headlights on if they where powered from the alt. directly reducing the power available to run thru the car to the battery. The best way is to recharge the battery before driving the car.  At work I can not take off if the the battery's are Charging at a high rate ,would have to wait until it drops or the better way and sometimes faster way is to have  maintenance swap in fresh battery's first. Don't want an overheated battery or thermal runaway in flight .
Good luck.

Thanks flyinlow... all really good practices to be sure.  I hope never to have to recover a fully discharged battery without charging it outside the vehicle first, but if I'm stuck and have no choice, I'll remember what you said.  I particularly like what you said about turning on the headlights to cut down the amount of power that's available to recharge a completely discharged battery.         

So, you did say "batteries" in your post... right?  Exactly how many batteries do you have in that trunk anyway??     

[flyinlow]

So, you did say "batteries" in your post... right?  Exactly how many batteries do you have in that trunk anyway??    

No trunk, electronics bay , was talking about being at work . A lot of commercial airliners used two 14V. nickle cadmium batterys in series for the 28V DC part of the electrical system.  Just one battery in the trunk of the Charger.   I guess Charger would be a good name for an electric car. 

[John_Kunkel]

I was thinking about adding an 8g or 6g wire from the the alt directly to the battery but switched with a heavy duty relay (100A). Then mount a small relay trigger switch inside the cabin.  

Why use a switch? I would run the #6 wire directly from the alternator lug across the core support to the battery. The ammeter won't be accurate but it should still show some charge/discharge.

[68neverlate]

No trunk, electronics bay , was talking about being at work . A lot of commercial airliners used two 14V. nickle cadmium batterys in series for the 28V DC part of the electrical system.  Just one battery in the trunk of the Charger.   

Wheew... that's a relief!  I thought for a moment there you had gone over to the dark side... trading your internal combustion for electric!       There would just be something terribly wrong with one of our cars rolling down the road to the whine of an electric motor rather than a ground-pounding big block!     

I guess Charger would be a good name for an electric car. 

Put the Charger on the charger!!   

[Nacho-RT74]

any late 70s alt is able to provide 40 amps alt at iddle. In fact Beck Arnley 78 amps replacements are spec'ed in that way. Now diff is try to build your stock 60's alt on those spoecs what will be really cool

to feed headlights relays you can feed ( and in fact will be the right way to the right amm reading ) from alt stud OR any portion of the wire on alt section of charging system.

However if you decide to fit a wire line between alt and starter relay, you are already modifying the ammeter reading so won't care at the end where you source the relays because its already bypassed.

[68neverlate]

I got some news on the alternator front today... I talked to the head tech at the electrical shop and he was pretty confident he could build me a Mopar alternator that looks stock that meets the 80 amp max output and 40 amps at idle specs I gave him.  He said I wasn't on the hook for it if it didn't generate the minimum 40 amps at idle.       If he can't satisfy the specs, I'm probably going to have to break down and go with a different alternator.  Hopefully he comes through...

An update on the alternator front... I just got my alternator back from the electrical shop and it looks great!        
All stock paint and look with a custom stator that puts out 100 amps and a whopping 50 amps at idle!!  All the while, looking completely stock.   

I'm really impressed with these guys... they sent alway to Toronto to have the stator custom built and then painted up and assembled everything when that came in.  All the power with the stock look...  I can hardly wait to get it in.  Still haven't started the wiring mods... life interupted those the past couple of weeks.  Hoping to get at it this week.  Looking forward to hearing the big block fire up again!   

[Nacho-RT74]

GREEAAAAT, some chance to get me built one for me ?

just teh stator is good enough, I can keep the rest of my pieces and built by myself

[68neverlate]

GREEAAAAT, some chance to get me built one for me ?

just teh stator is good enough, I can keep the rest of my pieces and built by myself

Anytime Nacho, you just say the word and I'll put the order in for you!   

Of course, shipping from me to you might cost you as much as the stator....     

[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!