Alternator gauge

[mikeydf14]

This has probably been asked a thousand times on here but here we go again. As most Charger owners know the alternator/amp gauge loves to dance wildly especially as I depress the accelerator.  My gauge is going crazy and we checked the battery and volt reg for correct output and it's doing the job correctly according to the service manual.  Several years ago some one was telling me of a way to get the gauge to stop it's bouncing dance by installing some sort of giddy gapper in the charging system.  My problem is I cannot remember what he said I could use to make the gauge stop the wild dance.  Now please realize that I do no know and ohm from an amp so electrical talk is beyond me.  Any help would be greatly appreciated.

[Nacho-RT74]

read this and will understand how it works, and how to solve it on a Mopar way

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

the first missconception it is... the ammeter is not really an alternator gauge, is a batt gauge... a simple idea can take you to the conclusion: AN ALTERNATOR IS NOT AN ACCUMULATOR THAT CAN BE DISCHARGED. AN ALTERNATOR CHARGES OR NOT, BUT NEVER GET DISCHARGED, HOWEVER WHY WE HAVE A DISCHARGE READING ON AMMETER ?

please, make yourself a favor... check the gauge on back for conditions ( loosen studs, rusty, dirty, loosen terminals ), same as bulkhead conectors, main red and black.

disconect battery first.... if amm studs are some loosen can short out with cluster housing

[mikeydf14]

Well one thing for sure is Nacho has a great mind for electrical issues....  At least from what I can read.  I will have to get this info to my buddy who knows how to read electric and then put it all to good use. If it leaks and I can see it and I can fix it. But those little electrons aren't easily seen.  Thanks for the assist Nacho!

[K9COP]

Mikey, read my recent post on the AMP gauge. I hear  ya re: electrics, they're a mystery to me too...

The AMP gauge, at this age, appears to be a sort of 'Mopar Russian Roulette' so please check, check and check again.

Good luck!

CS

[Pete in NH]

Hi,

The ammeter dancing between charge and discharge is really a function of the alternator producing little or no output at engine idle. The older original Chrysler alternators do not produce much output at idle so any load on the electrical system must be provided by the battery. So, the gauge reads discharge. As engine speed increases, so does the alternator output which can now pick up the electrical load, plus replace what has been taken out of the battery. In replacing that energy taken from the battery the gauge now reads charge. When accessories like  big sound systems and lights are added to our older cars the alternator can not keep up with the increased load at engine idle and tends to make this issue more pronounced.

Newer cars with their bigger electrical loads have bigger alternators that can provide more current at engine idle. Our cars have alternators in the 30 to 45 amp range from a day 40 years ago when there were fewer demands on a automotive electrical system. Putting these newer alternators on older cars can lead to other issues such as the wiring systems capacity to handle higher currents and the ammeters current rating, so alternator upgrades must be done with caution. Wiring upgrades and possibly changing the ammeter to a voltmeter might be required if going to a really high output alternator.

These 40 year old systems are what they are and trying to make them do what they were not designed to do is not a good idea. Some upgrades in the wiring and system maintenance are a good idea but, you are not going to make them into a modern automotive system  without a lot of work and careful planning.

[K9COP]

+ 1. What he said. I like this guy... 

CS

[Nacho-RT74]

everything will depend on what you want to do with your car.

-keep ammeter on car like stock is, which is not bad as far YOU KNOW AND UNDERSTAND how must work the system. And upgrade acording with it... that was my way because I'm an A$$h**e stockish guy LOL

-bypass ammeter because you don't care keep it like work stock your car

[mikeydf14]

Gentlemen I sincerely appreciate ALL of the inputs.  I finally had a talk with my electrical guy and I think we may have this licked so to speak and we are getting a new alternator (one wire?) that has a built in voltage regulator and retired the one on the firewall.  Thanks again.

[Nacho-RT74]

that's just a solution just if alternator sources enough.

The problem is not the regulator location or if internal or external, one wire or not... is the alternator hability to source the car at minimun RPMs as posible. If WHATEVER KIND OF ALT is able to source most of the car at minimun RPMs, you are done

[mikeydf14]

Would installing a Mopar Performance electronic ignition system make a difference?  If so, I have one in the car.

[mikeydf14]

Once the new alternator is installed we will have to see if this solves the low RPM issue.  I wish I learned more about electricity!!!!!!

[Nacho-RT74]

ignition system doesn't affect the charging system, but a bad charging system can DEFINITELLY affect the ignition system, overheating modules ( hence the lot of ECUs with back paste melted ) allong with some other problems

[mikeydf14]

Yes I do know that a bad charging system can mess up the ignition system so that's why I started this post to get specifics and everyone's helped.  Thanks Nacho for yours.

[69wannabe]

I have had good luck with the factory charging system on my charger til recently. I ran a 60 amp alternator with a plastic box looking regulator on my 69 for ever it seemed like. That regulator kicked the bucket a few years back so I went to the store where I purchased it and got the same part number (VR101 standard brand) but it was a points style regulator that didn't last no time and it went bad. Tried another one and it didn't last long either. Ordered a printed circuit style regulator supposed to be for use with electronic ignition conversions and it worked great and I thought I had it licked but it shorted out while driving one day and burnt the ignition feed wire up all the way back to the ignition switch!!! After hanging under the dash for and hour or so and repairing the wiring in and outside under the hood of the car and replacing regulator's I decided I was done with external single field regulators. My first thought was to do a dual field alternator and regulator (70 and up design) but that wouldn't necessarily look right on my car so started looking at one wire alternators. Didn't want to do a denso style since it was small and wouldn't look right either. Powermaster sells a natural finish double pulley one wire alternator for bout $160 bucks and its a 75 amp which shouldn't be too many amps for the factory wiring. I bought me one a few weeks ago and so far I like it and it charges good even at idle with the headlights on too. The alternator gauge doesn't bounce around as much as it used to either. I put another regulator on the firewall and ran some dummy wires to it so it would look like its there anyway. If this is what you are going to do let us know how it turns out!!!