Amp Gauge "Sorta" Bypass Question

-

RustyRatRod

I was born on a Monday. Not last Monday.
FABO Gold Member
Joined
Jun 7, 2010
Messages
104,330
Reaction score
101,465
Location
Georgia
Del @67Dart273 and other electrical gurus. I want to run a heavy gauge wire from alternator positive to the big lug on the starter relay. I've had NO issues whatsoever with the stock wiring, the firewall connector or amp gauge. I want to keep it that way. Will doing this help "unload" the amp gauge and help curtail any possible problems? I realize the amp gauge will not read "correctly" but I believe it will still read "good enough" to see that it is charging or discharging. Is all of this pretty much correct? Also, what gauge wire would be recommended?

Thank you drive through.
 
I’m no electrical guru by any means so I’ll state that right from the gitgo. So I reasoned if the factory used a single 12 gauge wire from the alternator, then 2 paired together should take the place of a larger gauge wire which I don’t have. Instead of running it as stock, i am running it through a maxifuse through to the battery positive as per wiring information I found through slantsixdanNo, I am not running an ammeter but a voltmeter in my Dakota Digital cluster. So your thoughts of running it to the stud on the starter relay I think it’s basically the same as what I’m doing except you’re not running through a fuse before connecting it to the stud.. waiting to hear what others think
 
Rob, i think what you will find is the accessories will be the only thing triggering the ammeter. Will likely show a continous discharge. personally i prefer a voltmeter,it provides more info typically.
 
but I believe it will still read "good enough" to see that it is charging or discharging.
No. It will only show discharging.
Battery charging will not show because the path of least resistance between the alt and the battery will be the new wire.
That's not just theory @Mopar Tim and others can tell you.
Stick one of those voltmeter's in the lighter socket. That will then give you some idea of whether the system is working. Might have to pull it out when the key is off. Sometimes they are wired to a fuse that's always hot.
 
Rob, i think what you will find is the accessories will be the only thing triggering the ammeter. Will likely show a continous discharge. personally i prefer a voltmeter,it provides more info typically.

I would like that, but as of yet, no one has been able to tell me how I can have my original amp gauge converted or if it can be done.
 
exactly what i did Rusty.
I used an 8 gauge wire and ran it through a fusable link to the starter relay.
You will quickly see where your new normal will be on the amp gauge...mine is a bit on the discharge side but still charges and discharges normally.
...been running this way for years now and indeed reduces flow through the bulkhead and ammeter.
 
exactly what i did Rusty.
I used an 8 gauge wire and ran it through a fusable link to the starter relay.
You will quickly see where your new normal will be on the amp gauge...mine is a bit on the discharge side but still charges and discharges normally.
...been running this way for years now and indeed reduces flow through the bulkhead and ammeter.

Does it always run on the discharge side? Even when going down the road? I want to know what "normal" is if I decide to do it. Thanks.
 
If you add a volt gauge you can tie it in to say your radio power (acc) so it only reads when the car is running. Someone bought a cheap autozone gauge and fit it to replace the Amp gauge in their cluster but damm if I can find it . I'd go 8 Ga to your starter jmo .
 
Does it always run on the discharge side? Even when going down the road? I want to know what "normal" is if I decide to do it. Thanks.
Normal will depend on the condition of each path to the items using electricity.
Imagine electrons flowing like a river.

Take your finger (any finger) and put it on the power source.
Now move your finger along the shortest path to whatever is using electricity.
Do this for every item using electricity.
upload_2021-7-16_9-43-32.png


Now do the same with the additional wire.
upload_2021-7-16_9-47-47.png
 
I understand that in this scenario the ammeter reading no longer provides any useful information.
 
Yes you can do it. It will work fine except the amp gauge.
 
Mine is a 64 Valiant. So far, unless I've missed it, there's not a conversion out there for it. I could be wrong. Kinds hope I am.
I'll have to take a pic of mine. But I don't thing you can buy one.
 
If the ammeter moves at all it won't tell you anything "truthful." Rob the big danger here is that you need to fuse/ breaker that bypass wire, as the fuse link is not protecting the new wire.

The "easy way" is to get a voltmeter

On a side note, a member here is sending me an "external shunt" ammeter out of a 76? car. My plan IF I LIVE LONG ENOUGH to get the 74 driving, is to experiment with it----I can "patch" the shunt ammeter into the STOCK harness and get some idea of how and "how easy" this can be implemented.

What this might mean EG is...........if you are like me and like ammeters, but want to fix the problem, you could (if this works out well) get an external shunt "junker" out of a Mopar/ Ford/ GM and adapt it into the ammeter shell the same way the voltmeter conversion was done........then wire it into the harness and "have your cake"

This would however, require some study to get the wiring "corrected" so the new shunt device would indicate correctly----same as the discussion here

Remember...........the general theory of car ammeters is...........

You want the alternator and all loads on one side,..........and the battery on the other..........

Sorry for the babble.........
 
Does it always run on the discharge side? Even when going down the road? I want to know what "normal" is if I decide to do it. Thanks.

Yes, just a tiny bit...but if your battery is low it will move to charge until the battery is normal. It will also move further in the discharge position when discharging.
 
Yes, just a tiny bit...but if your battery is low it will move to charge until the battery is normal. It will also move further in the discharge position when discharging.

I may have a solution. I had a volt gauge I forgot about. I tore the guts out, took the face off, swapped the face on from another amp gauge and glued the orange pointer on top of the volt gauge pointer. I just need to work out installing it into the cluster and wire it in. I'll go straight to the back of the fuse panel to the "acc" side so it's only hot with the key on and ground the other side. I'll go get pics of where I am now. That way, I can go ahead and just remove the amp gauge and bypass it altogether.
 
There is no shunt LOL

Yeah I noticed that. You've said time and again the amp gauge is actually a dead short and you ain't kiddin. That's EXACTLY what it is. LOL
 
I ran a 10 ga with a maxi fuse near each end from my alternator to the starter terminal. I left the original wiring. The ammeter stays close to center with very little movement to charge and discharge. I hung a volt meter under the dash to keep track of the charging system.
 
i don't think I have ever seen a volt gauge in any factory vehicle. Why do you guys want to
remove the ammeter? Just make sure your connections are clean and tight. If you're worried the by-pass will cut the current through the bulkhead and ammeter more than half.
 
i don't think I have ever seen a volt gauge in any factory vehicle. Why do you guys want to
remove the ammeter? Just make sure your connections are clean and tight. If you're worried the by-pass will cut the current through the bulkhead and ammeter more than half.
Actually Chrysler is one of very few who have a AMP gauge and not all of these have the shunt in the gauge.
I ran a 10 ga with a maxi fuse near each end from my alternator to the starter terminal. I left the original wiring. The ammeter stays close to center with very little movement to charge and discharge. I hung a volt meter under the dash to keep track of the charging system.
A fuse or fusible link at both ends is wrong unless one is lesser rating than other. Two of the same rating will protect one another.
 
-
Back
Top