Ammeter Quick Question and 95 AMP alternator question

[Nacho-RT74]

72RoadrunnerGTX was faster than me on the reply about that 100 amps ammeter LOL. That kind of ammeter was used on earlier 70 Chryslers and mids 70s A/B bodies ( and of course on next bodies productions, F, M etc… ) to replace the regular Full load ammeters. They are a remote reading gauge by milivolts variation between both ends of an external shunt wire being part of the engine wiring on engine bay. The coil built into the gauge is somehow a magnetic amplifier to allow the larger move to the needle by the smaller current ammount.

The use of diff models/bodies ammeters on some diff car is physically posible while the gauge is built similar. I meant if is pointing up or down for example. The distance between studs is the same on all or almost all ammeters, but not the indexing. Some cars have a lateral reading, like E bodies and I think A body Rallye clusters. 71/74 B bodies got even two diff gauges for the Rallye clusters. If they are Clock/tach cluster ammeter needle points down. If regular Rallye cluster, ammeter is pointing up, like the standard cluster

About the non centered needle... I have dealt with couple of ammeters with needles like that, hence why I know why I’m talking about.

 

[mrmolding]

That ammeter is designed to use an external shunt, movement is completely different, not a direct replacement for the ’70 rallye dash ammeter.

Any idea of what shunt to use if I can't find the other gauge?

Nevermind, I found one like in the pic. Thanks again!

 

[Nacho-RT74]

Any idea of what shunt to use if I can't find the other gauge?

I have being wondering about the same to change to the shunt system on my 74 Charger, using an M body ammeter which also got built in a warning led to indicate a low voltage rate. I guess the best will be get a donor harness from the right body To use the shunt wire And it’s wiring splices

Is not just the gauge but also the wiring which will require some mods. Not hard to do thought.

BTW, I edited my previous post while you reacted to it, so more info added

 

[mrmolding]

I have being wondering about the same to change to the shunt system on my 74 Charger, using an M body ammeter which also got built in a warning led to indicate a low voltage rate. I guess the best will be get a donor harness from the right body To use the shunt wire And it’s wiring splices

Is not just the gauge but also the wiring which will require some mods. Not hard to do thought.

BTW, I edited my previous post while you reacted to it, so more info added

Awesome! I look forward to seeing how you do it so I can copy it!

 

[Nacho-RT74]

Well, is a long therm project… first because I’m in Spain while my car is in Venezuela yet… and second because my car is in pieces right now… yet.

 

[mrmolding]

Well, is a long therm project… first because I’m in Spain while my car is in Venezuela yet… and second because my car is in pieces right now… yet.

Ok, so I've been thinking if I just put my OEM ammeter back in place for a while, and put in your mod with parallel wires or full bypass, is there anything inline that can be wired to the stock ammeter to prevent it from being knocked out of alignment like the OER gauge? Maybe I got a bad OER gauge, or the quality is not good. But I'm sure I'll still get the 40+ peg every now and then.

 

[72RoadrunnerGTX]

Ok, so I've been thinking if I just put my OEM ammeter back in place for a while, and put in your mod with parallel wires or full bypass, is there anything inline that can be wired to the stock ammeter to prevent it from being knocked out of alignment like the OER gauge? Maybe I got a bad OER gauge, or the quality is not good. But I'm sure I'll still get the 40+ peg every now and then.

You need to verify and correct the 40+ amp battery charging first, the OER gauge may not be that actuate, actual current may not be anywhere near that. A healthy fully charged battery is not going to draw anything close to 40 amps to recover from a start-up.

Again, as mentioned several times, an OE ammeter is not going suffer any damage if going over scale for brief periods of time.

 

[mrmolding]

You need to verify and correct the 40+ amp battery charging first, the OER gauge may not be that actuate, actual current may not be anywhere near that. A healthy fully charged battery is not going to draw anything close to 40 amps to recover from a start-up.

Again, as mentioned several times, an OE ammeter is not going suffer any damage if going over scale for brief periods of time.

Thanks!!! So OE yes, OER not so much.

 

[mrmolding]

That ammeter is designed to use an external shunt, movement is completely different, not a direct replacement for the ’70 rallye dash ammeter.

I know this is beating a dead horse, but I wanted to share other thoughts on using this type of gauge. Not sure if the OP found a solution, but encouraging!
Initial experimentation with external shunt ammeter

 

[Nacho-RT74]

just adding info... this would be the TIPICAL ammeter external shunt wire diagram. Some cars got some other splices to feed around some other devices, but this would be the tipical basic configuration.

As everybody can see, STILL on these ammeters setup, EVERYTHING is still feeded from the alt side of the charging netweork, NOTHING from batt side. This is on this case to keep the real reading on ammeter, since these ammeters won't be load stressed like the full load system


On these, the wires to the ammeter are tipically 16 or 14 gauge. Once the gauge has been changed, upgraded, installed, the wiring itself is not hard to make. The existant ammeter wires and bulkhead paths can be reused fo feed the ammeter. Yes they are 12 gauge on our full load cars, not a problem on that. The main splice path will need to remake from the existant one down the harness tape thought.

I don't consider the fuse link running to the main splice REALLY necesary, since the system is still being protected by the main one on starter relay line, but doesn't hurt to have one there anyway.
as you noticed on the Abodies forum, the last Dart built ( 76 ) got this ammeter and they are really close to the 68/70 ammeter. Still rated at 40 amps thought.

76 Darts got in fact 32 circuits bulkhead instead 24 of previous models. This was because the main line also run throught the bulkhead, not throught the firewall with a grommet, along with some other accesories added to them like the pacer fuel warning light ( using the left fender turning signal indicator ), and stuff like that.

Honestly, 40 amps ammeter is still quite enough to get the car nicelly monitorized still having a 100 amps or more alts As mentioned what rules the amperes request is the car demand not the alternator output. I can understand the exiting idea about having a larger reading ammeter thought. Your batt will never suck 30-40 amps for long time still being fully discharged, only on inital stages, then will stay on 20-25 amps recharge rate for sometime getting lowered and lowered throught the running time. This has been my personal experience being on that scenario using a 80 amps alt. Recharge a fully discharged batt on car is not a right procedure anyway, AND if you still are in need of that ( because you are on the road ), having lights on or heater-AC blower turned on while charging the batt will get the ammeter less stressed because these added loads will take part of the extra alternator sourcing. Firewall path will be stressed anyway to feed the main splice into the cab allong with the load running to the discharged batt, hence why bypass the bulkhead.

 

[4406bbl]

That diagram is the way they all should be fed even with a voltmeter and no external shunt wire. Not to disagree with Nacho on both fusible links, but with a high output alternator I would run a 4 or 6 GA wire from the alternator to the battery or starter relay with a 10 GA fusible link, and also protect the internal car wiring with the 14-16 gauge fusible link, size depending on whether you upgrade the internal wiring. It is wise to put the small fusible link on the alternator side of the large fusible link and eliminate the original fusible link so you do not end up with fuse links in parallel at the battery or starter relay, as that is unsafe.

 

[4406bbl]

I should also add that all fusible links belong under the hood, not inside of the car.

 

[mrmolding]

Thanks as always! In my case, I'm pretty convinced that the 95 AMP Powermaster caused the OER ammeter to get out of alignment, so getting another OER might be a waste of money.

So, what about a more voltmeter type of update approach on using the 1976 ammeter. What about using a charge wire from B+ to the starter relay and leaving everything else in place. If I wanted to remove the original ammeter and put in the 1976 style ammeter and consider it more like a new gauge, how would it be wired in? Just trying to think about how to do this and not drill through the firewall and/or not waste money on another OER gauge. My car was very happy with the charge wire from Crackedback and an under the dash voltmeter. Wondering if I could just add in the 1976 style ammeter, change the face, and use it as a new gauge, but in the original ammeter/alternator opening in the dash.

Apologies in advance, if I'm thinking of crazy ideas.

 

[Nacho-RT74]

That diagram is the way they all should be fed even with a voltmeter and no external shunt wire. Not to disagree with Nacho on both fusible links, but with a high output alternator I would run a 4 or 6 GA wire from the alternator to the battery or starter relay with a 10 GA fusible link, and also protect the internal car wiring with the 14-16 gauge fusible link, size depending on whether you upgrade the internal wiring. It is wise to put the small fusible link on the alternator side of the large fusible link and eliminate the original fusible link so you do not end up with fuse links in parallel at the battery or starter relay, as that is unsafe.

Voltimeter is tipically attached on a switched line.

once again, the high output alternator doesn’t rule the load running throught the circuits, but the load requested by the devices. The car will request the same load with a 50 amps alt than with a 500 amps alt, but the higher unit will source a more stablish power and the car will never require battery assistance from the batt when alt is not capable.

The only source able to feed without fail a big short is the battery because aside the fuse link or any other protection, nothing will stop the batt to feed the short. If a car runs just with alt and a big short floats on, engine will stall because regulator and ign system will fail trying to keep on the system and short will be gone. Hence why a fuse link is not really required on alt line.

into the cab, everything is protected by the fuse box, except ign switch and all the wires coming in/out from main splice, but the devices they source are protected.

 

[Nacho-RT74]

If I wanted to remove the original ammeter and put in the 1976 style ammeter and consider it more like a new gauge, how would it be wired in? Just trying to think about how to do this and not drill through the firewall and/or not waste money on another OER gauge. My car was very happy with the charge wire from Crackedback and an under the dash voltmeter. Wondering if I could just add in the 1976 style ammeter, change the face, and use it as a new gauge, but in the original ammeter/alternator opening in the dash.

Apologies in advance, if I'm thinking of crazy ideas.

already posted on diagram. And yes, I’m pretty sure you can use the later amm onto the existant provision changing the face. Studs gaps is pretty much the same so no mods to the cluster… now diff stuff is if the A body amm is the same deepness than the 68-70 B body. Maybe will need to trim out the needle and paint it white too.

A body cluster never changed between full load and external shunt amms. Sure the PCB changed to source it diff, but not the housing or bezels, so this amm is a straight change into the older and last A body cluster.

on both cases… stock full load amm or newer external shunt amm, the bulkhead bypass through the firewall is the best way to go.

 

[mrmolding]

Voltimeter is tipically attached on a switched line.

once again, the high output alternator doesn’t rule the load running throught the circuits, but the load requested by the devices. The car will request the same load with a 50 amps alt than with a 500 amps alt, but the higher unit will source a more stablish power and the car will never require battery assistance from the batt when alt is not capable.

The only source able to feed without fail a big short is the battery because aside the fuse link or any other protection, nothing will stop the batt to feed the short. If a car runs just with alt and a big short floats on, engine will stall because regulator and ign system will fail trying to keep on the system and short will be gone. Hence why a fuse link is not really required on alt line.

into the cab, everything is protected by the fuse box, except ign switch and all the wires coming in/out from main splice, but the devices they source are protected.

Fair enough! I figured it was worth a question! THANKS AS ALWAYS!!!

 

[4406bbl]

Voltimeter is tipically attached on a switched line.

once again, the high output alternator doesn’t rule the load running throught the circuits, but the load requested by the devices. The car will request the same load with a 50 amps alt than with a 500 amps alt, but the higher unit will source a more stablish power and the car will never require battery assistance from the batt when alt is not capable.

The only source able to feed without fail a big short is the battery because aside the fuse link or any other protection, nothing will stop the batt to feed the short. If a car runs just with alt and a big short floats on, engine will stall because regulator and ign system will fail trying to keep on the system and short will be gone. Hence why a fuse link is not really required on alt line.

into the cab, everything is protected by the fuse box, except ign switch and all the wires coming in/out from main splice, but the devices they source are protected.

We will have to disagree on that, the line to the alternator needs fusible link protection, and should be sized to handle the max alternator output. I understand the battery cannot accept that much charge but a rubbed thru wire, or an accident as in a wreck could cause a short and a fire.

 

[Nacho-RT74]

There is room to be disagree, not a problem ;). Add a fuse link there won’t hurt anyway. But you can try test. Start up the engine, disconnect the battery and make by yourself an intentional short between alt stud and chassis. You’ll see the engine coughing then stalling almost immediatelly. No engine running, not power anymore. So the batt if connected will be the only source able to feed the line, then fuse link would blow

 

[mrmolding]

So I wanted to share...not sure if I'll ever do this with a newer ammeter. But, since I was not able to find a 77 Monaco service manual on mymopar, I bought one off eBay. It has the factory wiring diagram with the newer shunt that Nacho mentions above. I wanted to include that section from the manual just because I find it VERY interesting! Again, who knows if I'll do this but nice to have the info from the factory.

 

[69_A12_6BBL]

In my 70 RR, I have all new harnesses, new OER gauges, except the rebuilt speedo from Redline (just wanted to plug the awesome work), and a new PowerMaster 95 AMP alternator, new NAPA battery, new Voltage Regulator and a Voltmeter that I added under the dash.

I actually like seeing the Ammeter since I grew up with one. I also know that Nacho has outlined an improved way to use an ammeter -- thinking about doing that.

So here is what I observe -- When I first start the car, the ammeter needle jumps to pegged right/positive but then settles down quickly and just slowly moves down to the 0 position and stays there.

What I think is happening -- I'm not an expert, but I think that the Voltage regulator is doing its job and bringing down the AMPs. I could be wrong, but I've read a few threads, and this seems to be what is happening.

Other things I've tried -- I do have a charge wire that I got from CrackedBack as part of his headlight harness. When I use the charge wire the ammeter of course just does not work but the concern goes away.
I've also tried a NOS 65-amp alternator I got from another member, but it squeaks, so I put the PowerMaster 95 AMP back.

Here is my question -- Do I need to be concerned about the initial high reading? Use a 100AMP shunt? Do Nacho's change so I can have the best of both worlds? Find a better older 46 AMP alternator?

Thoughts? In my day I was mainly a body/fabricator and mechanic's helper in my twenties so I'm slowly learning everything else.

NO. This "Pegging out" or Regulator On condition is there with all of us who don't start them 2 times a day as with driving it Back/Forth to work. Personally? I can't see any need for a Voltmeter. Espacially since that AWESOME factory Ammeter is just, the coolest guage in the dash! Voltmeter also may cause a little more resiatance in your Alternator feed side of harness. Probably not a big deal yet? I run a Powermaster 95 amp Alt. Only due to getting caught out after sunset a few times & needing the lights on. (OMG No! Right?) If that "Squeek" from the 65 amp is over annoying? May try a squirt of "Belt Dressing" (spray can from parts store). The squeek or squeal CAN also be something else such as BAD bearings in the alternator! Always carry a spare belt for everything. Along with, fuses, few Lug Nuts, HOSES & clamps and definitely 3/8" and or 5/16" fuel line Hose! (Ya never know!)
[I'd take one of the non-being-used alternators with me as well!] Hope that was some help. You'll find the ones that know a lot of electrical? Will usually all think the same way. "Gut it and go with New Harnesses". Have a fantastic weekend!
#moparOrNoCar