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

[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