ammeter upgrade (note to share with Tim/Charger RT and lot of ppl more )

[Nacho-RT74]

Maybe I mentioned Charger RT ( Tim ) because he recently floated on with lot of electrician knowledgement. Beside him I know more ppl like Brock, 71 deputy will be able to share opinions.

look what I found!

NOS 77 and later Lebaron ammeter!!!

even I'm in electricity world, I don't know everything about, so I wanted to share at least with all you guys( or whatever who knows about ) about the idea...

since we know about the low capacity of our ammeters ( up to 40 amps ) I was thinking about the idea to change the internals of the stock ammeter. Not needing now really, but on a later alt upgrade to 80-100 amps unit.

I think this lebaron unit is a heavy duty unit based on the coil I'm able to see on this, what I think is what is called SHUNT!!! but dunno if this unit is 60 or 80 amps scale. anyone of both will work because is way better than a 40 amps ammeter.

beside that, does have a bulb/led, that maybe is like the Batt lights on newer cars cluster. 

what do you think about ?

There are more of these ammeter units with the coil/shunt however dunno about lebaron units with the led/light, I know there are Aspen ones, without the light/led. Some other models too, but not everyone with needle coming from top or bottom. So if anyone is interested I could search more of these.

( studs width is the same in all units )





( note, this pic is being updated today Ap 16 2017, because previous image link was not working anymore )

[2Gunz]

A SHUNT is an electrical bypass device. Its function depends on what your doing.

In this case a SHUNT would be a bypass of a known electrical resistance used to allow a low amperage device to meter a much higher amperage circuit.

Basically you wire a SHUNT in parallel with the amp gauge. Most of the "power" flows through the SHUNT and what doesnt is metered by the gauge.

Since the SHUNT is a known value, by metering "whats left" flowing through the amp gauge it is possible to come up with a fairly accurate reading.

So lets say you have a amp gauge and a shunt wired in......

The meter reads 5 but you know that the SHUNT is flowing 10x that amount. So really the gauge is telling you that you are drawing 50 amps.

It could be tricky to accurately calibrate the amp gauge.  But since we are not launching a space shuttle and all your looking for is a very rough
charge/ discharge gauge it should be simple.

Anyway If you really want to do this.......

I would just use the stock gauge install a SHUNT and mess with the calibration of it. It might be easier in the long run if you remove the existing
internal shunt on the amp gauge.

Here are a few links for you.  I thought about doing this awhile ago, but Im not a fan of the amp gauge in general unless its done using the "hall effect",
so I didnt persue it.


http://www.jamestowndistributors.com/userportal/document.do?docId=126&title=Sizing+a+Shunt+to+a+DC+Ammeter

http://home.cogeco.ca/~rpaisley4/Ammeter.html

[2Gunz]

Oh and really the best way Nacho would be to build a hall effect amp gauge. However I dont think its possible to figure out if its a charge/discharge situation by doing that.

[Nacho-RT74]

I think I have some reading around about some shunts. will read these you posted later.


whats the coil for on the ammeter on pic then ? is a shunt or not ?

[2Gunz]

im not familiar with the gauge so I cant say for sure.

A shunt is just a fancy resistor so the coil could be.......

But my guess is the coil creates a magnetic field and moves the needle.

Have some better pictures?

[71_deputy]

yes the coil creates either a + or - magnetic field that moves the needle.  your right about the shunt in the later years- cars and trucks had the same setup.  basically there is a wire- size and resistance is made so that as stated- like 50 amps in the shunt will cause about 5 millivolts in the gauge- really the amp gauge is really a sensative current meter!!!!

the red led is a warning light that the voltage is above or below a set value- lets say about 11 to 15 volts to let you know something is wrong.  on the back of the guage is 4 terminals- two like our old beasts for the amp guage- other two are smaller pins types- one is for ground and the other is the sensing + voltage for the warning led.
temp gauge is the same as well as the gas gauge for warning except the sample the voltage from the gauge itself!!!!

John Mac- looking at this setup for a few years ago!!!

[Charger RT]

I like your thinking. It should be a higher amp meter. Can it be fitted into our dashes and appear factory?

I brought my wire chart home but wanted to get my tape measure out to guess the the lenght of wire these charging systems use from alternator to amp meter, amp meter to starter relay and from starter relay to battery. Because the total of those 3 lenghts is what is needed to determine wire size for the charging circuit. Now keep in mind the chart I am using is what is used today. This was not the standard back when our cars were built. But the fact that in stock form our cars meltd plugs wires and what ever else they melted shows that the standards needed upgraded. To run 35 amps (I believe the size of the OEM alternator) a 10 gauge wire can run that load but only for 5.5 feet. 8 gauge wire for 9 feet. I don't think the charge wire was even that big. So now lets bump up to the 60 amp alternator and recheck wire size that would be needed. 10 gauge is good for 3 feet and 8 gauge is good for 5 feet. This is why I feel a short run straight to the battery is best. If you use a 6 gauge wire around the back of the engine and back to the battery 6 gauge can work for 8 feet. That might be able to be done. So as you can see with modern standards and old cars that prove the factory system was not up to the job. It is much better to think modern. I like my amp meter as much as anybody else. But I want reliability day in day out.

The type of shunt amp meter I was talking about is one where the shunt is separate from the meter. We could upgrade our under hood wires to run a decend size wire from the alternator to the starter relay. and the shunt would be installed in the run of wire from the starter relay to the battery. Then all that is needed is to run 2 small gauge wires from that shunt inside to the new meter. (but for my car it would have to be redone to match my dash perfect). That link where the guy bypassed the amp meter on the dodge truck has a good idea. with the way he redid the wiring on that car he doubled the size of the wire running inside to the load of the car and removed any alternator amps that would go back to the battery to recharge it. I would tie the amp meter wires together inside like he did. Cut the alternator wire near the starter relay and hook the piece going inside the car to the starter relay. the remaining piece from the cut to the alternator I would discard and run my new heavier gauge from the alternator to the starter relay. Then replace the run from the starter relay to the battery with the same size wire running from the alternator. with the shunt installed in this run of wire. With it this way all the high amp loads are kept under the hood in shorter runs. The amp meter would work correct too. I hope this ebay link works where you are because it shows a perfect example of the setup I was talking about. This one wouldn't work but the pictures of it wired up are very helpful to understand the setup.
http://cgi.ebay.com/ANALOG-DC-CURRENT-METER-AMMETER-30A-W-30-A-AMP-SHUNT-RV_W0QQitemZ310151317984QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item48367589e0&_trksid=p3286.c0.m14
Tim

[Nacho-RT74]

well yes... I thought LOOONG TIME AGO ON ADD somekind of resistor wire between ammeter studs ITSELF to help on the current throught the ammeter, giving at least an aproximatelly idea about the charging status, but that was just my personal idea without NEVER have heard about a "shunt" or whatever similar assembly. So I wasn't wrong when I though on that around 4 years ago. Not bad for me  



Well this is a Mopar ammeter used on lates cars FULLY equipped ( lebarons/diplomats ) with higher STOCK amperage alts, so should work. What I dunno is how much is the scale read. Somebody posted a standart 3rd gen rallye cluster from a Police package car with 80 amps ammeter and DID IT HAVE THIS SAME COIL!

Can it be fitted into our dashes and appear factory?

I'm talking about FIT JUST INTERNALS keeping the face. Studs width is the same in all Mopars, the only deal could it be the deep between face and back of studs. If measurement is the same will be easy like replace small rivets. The deal is try to find correct rivets LOL. The extra terminals only requires a small drill.

Honestly everything should fit, because along the years I have seen all the internals from ammeter to ammeter being basically teh same and just cahnging the face or needle size. I think even the rivets locations!

If this gauge is too deep, the housing where face is riveted is thick plastic so it could be milled down at least 1 milimeter.

If somebody is toward to this idea I can get you more of these, but dunno how many Lebaron Units still rest with the light. I know there are some Aspens but I can't recall if needle is toward up or down. I know there are another ammeter around from dunno what Mopar, but being needle toward up. Will work to 2nd gens and Standart 3rd gen clusters. Also Rallye clusters without clock/tach. Everyone of what I'm talking is with this coil on pic

So John.... you think THIS coil on ammeter is somekind of shunt ar really works to this purpouse ? then is the light VOLTAGE reading ? that will be great because will get somekind of two gauges on one!!!

I can find Lebaron diagram to check the ammeter 2 extra terminals hook up. Haynes manual carries those.

Gunz... I'll try to get you better pics

However will be GREAT try to get a non working ammeter gauge better to make this!!!! I don't need to make this job yet since RIGHT NOW my ammeter does have full headroom with what I have now, but looking forward.

[2Gunz]

Putting the shunt under the hood is logical.
Need to see what if any affect the length of the gauges wires would have.

But really IMHO the best thing would be to make the amp gauge into a volt gauge.

[2Gunz]

I think just using the original gauge makes the most sense.

I dont have one to take apart but it must have its own internal shunt device of some sort.
Just remove it.... wire the gauge add a larger Shunt and calibrate it.

[Nacho-RT74]

I have 8 parallel gauge plus the stock gauge running together on alt side. I'm not really worried about power loss. Enough gauge there to beat any resistance.

On red side I have 10 and the stock one... still enough gauge once you run together.

Come on!! the fuse links makes more resistance than all the wire lenght!

Lenght diff will be NO MORE than 40-50% if you run directly instead the original run to ammeter. I don't think that will be something to worry on a street car. The probably power loss on this it could be something to worry on a Race car.

If that is something to worry, put batts on trunk makes a non sense way ( beside save the batt from heat and win there something )

[Nacho-RT74]

sometime ago was posted this pic:



71/74 standart cluster B body police car gauges

now I'm hoping who post that will still have the ammeter to look at the back of and check for that coil. Just sent a PM to the owner.

this ammeter was mounted on a car with a Leece neville 100 amps alt

[2Gunz]

I have 8 parallel gauge plus the stock gauge running together on alt side. I'm not really worried about power loss. Enough gauge there to beat any resistance.

On red side I have 10 and the stock one... still enough gauge once you run together.

Come on!! the fuse links makes more resistance than all the wire lenght!

Lenght diff will be NO MORE than 40-50% if you run directly instead the original run to ammeter. I don't think that will be something to worry on a street car. The probably power loss on this it could be something to worry on a Race car.

If that is something to worry, put batts on trunk makes a non sense way ( beside save the batt from heat and win there something )

I ment the effect of wire lenght on the gauge if you put the shunt next to the starter really then run like 18guage wire inside to the meter.

[Nacho-RT74]

yes, you are right Gunz... dunno if I would make that modification myself, but is a good idea!

BTW

JUST REMEMBERED THIS thread!!

http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Board=QuestionAnswer&Number=5261042&Searchpage=6&Main=5257986&Words=ambulance+%2Bammeter&topic=&Search=true#Post5261042

[71_deputy]

Natcho- here is a pic from a 1980 car manual showing the shunt wire- most I have seen has the shunt wire right before the bulkhead harness- then two smaller wires go thur the bulkhead to the amp gauge. any other power required in the car went via a different wire thur the bulkhead!!!

so to do this you need to find a late years car or even truck to get the harness to do the changes with the shunt wire/meter!

[71_deputy]

my mistake- it's really a sensitive current meter!!!!

[Nacho-RT74]

so then DOES WORK like Gunz stated on his last replay.

if so, then the ammeter studs can't be done like splice point, as original are from factory are our cars. And this ammeter I got won't support the stock load!

I was thinking on this because took a detailed view inside the amm, and studs only get the coil leads inside, nothing more... definitelly wouln't support the regular load. Thanks God I started this thread

Will check some other diagrams around.

Does the 80 amps unit on pic from a police car would get the shunt too ? I haven't found ANY diagram from earlier cars showing Shunts, and who took the pic told the ammeter got on studs HEAVY WIRES to it.

[71_deputy]

so then DOES WORK like Gunz stated on his last replay.

if so, then the ammeter studs can't be done like splice point, as original are from factory are our cars. And this ammeter I got won't support the stock load!

correct!

I was thinking on this because took a detailed view inside the amm, and studs only get the coil leads inside, nothing more... definitelly wouln't support the regular load. Thanks God I started this thread

correct!

Does the 80 amps unit on pic from a police car would get the shunt too ? I haven't found ANY diagram from earlier cars showing Shunts, and who took the pic told the ammeter got on studs HEAVY WIRES to it.

now what I see for the early years cars is that the heavy power wires went throught the firewall( not the bulkhead harness connectors) via a grommet and then to the amp meter studs. not sure if the existing wiring was still there to the inside bulkhead connections and then also connected to the amp meter studs for power elsewhere in the car.- this would make sense as they probley didn't want to make a whole different harness for the dash!!!-they just connect the new haevy harness to the amp studs!!!  just my 2 cents here!!!

[71_deputy]

ok- looked at a 1974 manual- found the heavy power wires and the grommet going to the amp meter studs with power taken off the studs for inside power!!!!!   this was for the fleet cars- cops, taxis!

[Nacho-RT74]

Yes John, thats what I made here ( as you know )

http://www.dodgecharger.com/forum/index.php/topic,33574.0.html

I didn't invent anything as I always stated, just refreshed and made a public knowledgement about. AND STATED MADELECTRICAL website is wrong on some statements they do. I gave the theory about how the power runs throught the system

However as you can see the 80 amps unit pic from 71/74 B body I posted will be apparently driving the full power, being THERE IS NOT ANY SHUNT ON THESE YEARS MODELS  stated on diagrams, and who found the unit, stated it got HEAVY WIRES. Still waiting for backside pic view to check for that coil existance.

A generic UPGRADE diagram for shunt and "coiled" ammeter units will be then:

[Nacho-RT74]

for a car with already all the wiring upgrade made OR WIRED IN THAT WAY FROM FACTORY and make an easier mod over on an already job made this could work.

THE FACT IS, SHUNT AND "COILED" ammeters go HAND BY HAND. You can't mount a later ammeter with this coil WITHOUT a SHUNT, and you can't fit a SHUNT with regular ammeter because won't get any reading ( or will be incorrect ). Would it be allmost the same than run a direct wire from alt to starter relay/batt.

So make JUST the ammeter inners upgrade won't work for me by the moments

[tan top]

sorry for the hyjack sort of  guys , just  reading , how would you wire up a battery/ ignition lamp , like modern cars have , in our old mopars   with the original alternators , been trying to figure out for a while ,

[Nacho-RT74]

keeping in fact the heavy wires on ammeter studs and just runing the shunt between them should work too.

I already thought on this LOOOOONG TIME AGO, but I didn't know all the details about all the diff ammeters came out later and the Shunts, but is a fact I thought on tie somekind of wire resistor stuff between amm studs and making able to drive more power with wire and ammeter together

Everything on this is because the fact I preffer ammeters to know the charging system status. Ammeter readings are WAAAAY more sensitive to the charge status than voltimeters, so then changes are more noticeable. More less like compare an oil gauge and an oil light ( that was extreme LOL )

[71_deputy]

looks good to me!!!!!!!!!

[Nacho-RT74]

Now... How I determine the SHUNT spec, resistance or whatever ?

[Nacho-RT74]

sorry for the hyjack sort of  guys , just  reading , how would you wire up a battery/ ignition lamp , like modern cars have , in our old mopars  with the original alternators , been trying to figure out for a while ,

yes, that will be nice to know too.

[tan top]

sorry for the hyjack sort of  guys , just  reading , how would you wire up a battery/ ignition lamp , like modern cars have , in our old mopars   with the original alternators , been trying to figure out for a while ,

yes, that will be nice to know too.

yeah   , been trying to work out if & what any late model mopars have them , with the same type of alternator as we have  , the try following the wires to see where how they hook up      

[Charger RT]

sorry for the hyjack sort of  guys , just  reading , how would you wire up a battery/ ignition lamp , like modern cars have , in our old mopars   with the original alternators , been trying to figure out for a while ,

are you saying you want to add a light to light the ignition switch when you open the door and shut off automaticly after 20 seconds or so after the door is closed like modern cars?
Tim

[Nacho-RT74]

no, he means about the BATT light that turns on when some electrical fail ( and when engine is shut off )

[Charger RT]

If that is the case it can be tough. The idiots light s usually work with a stator wire from the alternator. Our alternators do not have a terminal for stator. They were wired key power to one terminal of a light bulb the other terminal of the bulb goes to the stator terminal. key on and not charging the stator provides a ground or actually enough of a ground to complete the circuit andd the light comes on. Start the engine and the alternator starts to charge and the stator wire changes to a hot wire. now with the bulb having a hot wire on each terminal the light goes off. Too bad we don't have a stator wire because they also work great to power an electric choke.
Tim

[Nacho-RT74]

well on squareback alts stator have eyelet terminals arriving to diodes bank studs ( not solded like earliers ). If you need a stator lead, you need just to take a wire from there to outside the alt through diodes square holes.

with some more imagination it could be done on roundbacks too thought.

coming back to topic...

is the shunt simply a regular wire or does have some special specification ?

Will the shunt work the same between amm studs being shorter lenght like on last diagram I posted ?

is it some diagram I made wrong ?

[2Gunz]

I would say that any amp gauge has a shunt in it.  Running 40+ amps through a wire the size of a thread just isnt going to happen.

As far as the amp gauge being more sensitive I agree. But in reality what is it that you need to know? The battey is charging or
its not.  And that can be done with a volt meter.

There is a reason that new cars dont have amp gauges..... and its not because they where a great idea.


The one page I linked you had the formula for figuring out what you need.



If you REALLY want to know what is going on......  why not put in a volt gauge in the stock location then use a Hall effect meter and clamp to
figure out amperage.

[tan top]

no, he means about the BATT light that turns on when some electrical fail ( and when engine is shut off )

yeah thats it Natcho  was thinking it would a quicker warning if i lost a water pump / alternator belt at speed ,  so i would not cook the motor
sorry for the hijack 
back to shunt & ampmeter stuff 

[Charger RT]

no, he means about the BATT light that turns on when some electrical fail ( and when engine is shut off )

yeah thats it Natcho  was thinking it would a quicker warning if i lost a water pump / alternator belt at speed ,  so i would not cook the motor
sorry for the hijack 
back to shunt & ampmeter stuff 

Well back to the hyjack. If you want to protect your motor just add a shut down system. Diesel trucks have used add on systems for years and now that they are computer controlled they are built right into there computers. The add on systems can be used for a gass engine with no issues.


Now back on track. The whole idea of the shunt is to put it under the hood and shorten the alternator wire lenght back to the battery. Adding the unit in the dash still requires a much longer wire. This would require a heavier gauge wire. Also the run back to the battery should have as few or no splices as possible. Thats why I said run one solid wire from the alternator to starter relay. Replace the wire from the battery to starter relay and put the shunt there. This way it shortens the run from alternator to battery as short as is possisble and does not require the system to need a heavier gauge wire. The amp meter would work just like it did to begin with. As far as wire size from the shunt into the the gauge the circuit now becomes a low current circuit and a small gauge wire will work just fine.


I still think a volt meter is more then enough to check a charging system and can be hooked up inside the car without running wires all over the place. But for the diehard amp gauge people this to me is the most sensible way to keep a gauge and upgrade the electrical system to a more reliable system.
Tim

[71_deputy]

I'll check my truck harness in the shop this weekend to see if I can measure the resistance of the shunt wire.  length of the wire is about 6-8 inches- will measure too. if the wiring is the same size all the way to the amp meter I guess you could put it on the back of the meter studs.  purpose of the shunt in the engine bay was to prevent all the power thur the meter and the stock firewall harness as each year the demand for power in the cars outweighed the stock wiring and terminals!!

the led light in the later guage for warning is really just a voltage comparator- when it is out of range the led lights up!!!it is power via the dark blue ing. power

[Nacho-RT74]

The wire I used for my parallel wire up to ammeter was removed from a 75 or 76 Coronet from where I took several harnesses and used some of its wiring to replace mine about 6 years ago. Is there a chance I ALREADY HAVE A SHUNT WIRE between the sections of wiring ?

On those days I still din't know what I know now, so dunno if 75/76 coronets got that kind of assembly and I got everything without know it.

[Nacho-RT74]

I would say that any amp gauge has a shunt in it.  Running 40+ amps through a wire the size of a thread just isnt going to happen.

Our cars doesn't have shunt in amms. The ammeter is in fact like a wire. but being a metallic strip where studs are conected. I wouldn't consider that a "shunt" simple because if a shunt is a "bypass" when the metallic strip is not a bypass, is the main run that gets the full power to create the magnetic field to move the needle.

As far as the amp gauge being more sensitive I agree. But in reality what is it that you need to know? The battey is charging or
its not.  And that can be done with a volt meter.

I still trust more on a ammeter whatever volt also works . Both together is better of course, but would it be like getting an oil gauge and an idiot oil light

There is a reason that new cars dont have amp gauges..... and its not because they where a great idea.

also because newer cars are made for new idiot drivers LOL that suppossely doesn't need to know what is happening oon his car. Whatever problem TAKE IT TO A DEALER OR MECH SHOP.

Also is one more gauge, more cost, then susbtituted by idiot lights. Not too much cars get voltmeters either

The one page I linked you had the formula for figuring out what you need.

YES! Thanks!... I bookmarked, will read later. ( sorry I have been some lazy LOL )

If you REALLY want to know what is going on......  why not put in a volt gauge in the stock location then use a Hall effect meter and clamp to
figure out amperage.

naaah, I don want to modify anything or get hanging out a non stock gauge below the dash. Just have a tach ( the smaller I could get ) because I couln't find an affordable hood dixco tach.

And I like the stock cluster working like suppose it is from factory. Got an ammeter, then will keep an ammeter on cluster. Isn't great get an old car working like designed from factory ?

[71_deputy]

OK- FINALLY GOT SOME TIME TO DIG THUR THE SHOP AND FIND THIS 80'S TRUCK HARNESS- sorry about caps!!!

measured the shunt wire- couldn't get exact ohms as the meters these days can't do it below 1 ohm!!! so it measued 0 ohm's!!!!!

check the diagram posted!

[Nacho-RT74]

mmm you know that I was thinking the real "resistance" would it be the diff gauge ?. With a multimeter allways will get 0 ohms because the power going through from a multimeter is too small to get some resistance on wire.

not sure though