Ammeter General Questions

[jforest1]

1.  What does a working Ammeter do?  I assume when I'm idling it sits somewhere in the middle between D and C and when I'm at WOT, I should see it move up, yeah?  If so, I think mine's not working.

2.  Why would I use a voltage meter versus an ammeter.

3.  I'm currently in an alternator upgrade from 60 to 200amp alternator.  It occurred to me that this may cause problems with the Ammeter.  Do I need to upgrade the ammeter as well?  Doing a quick search, I'm not seeing any for my rallye dash save the original reproduction ones.  What are my options here?
 
Thanks!

JF
 

[Jesus H Chrysler]

The ammeter measures current flow from alternator to the battery and vehicle electronics. The C and D stand for Charge and Discharge.  This is usually referenced from the battery.  When your battery is fully charged and you aren't drawing much current in the vehicle (headlights etc) it should stay in the middle.  Revving the engine usually doesn't make it move.  If it moves a lot that means you either have a discharged battery or are drawing a lot of power somewhere. 

The downside of the ammeter and why most people bypass it is that ALL of the alternators power has to go through it.  This means if you have a discharged battery or running a thumping sound system, all that amperage has to go through your firewall, through the gauge, back through the firewall and on to the rest of the system.  Wires can melt and connectors can fail this way.  Also most stock ammeters are only calibrated up to 60 amps or so.  Upgrading the alternator and leaving the stock wiring is a sure way to burn your car down.

A volt meter by comparison can be tapped in practically anywhere.  it measures the voltage present in the system (usually 12-14 V).  If your volts are high or low, it can indicate similar problems as if your amps were high or low.  The difference is when diagnosing problems the volt meter would read opposite of the ammeter for the same problem.   The plus side is that the wiring in the vehicle can be rerouted so the major power wires are shorter and more concise.  This means you no longer have to route through the firewall and less wire and connectors to melt or fail.  Another plus is you can upgrade the alternator all you want and the voltmeter will read the same.

Search around the internet and I'm sure you'll find lots of info on how to bypass the ammeter and rewire the charging circuit.  It may not be "factory correct" but if you are upgrading the car it is definitely one of the must do mods.

[Bullitt-]

You would see the ammeter go the the charge side if your battery needed charging (I saw in another post you have 2-wires coming off your alt which effectivly disables the ammeters function if one bypasses it)....YOU DO NOT want to use the stock ammeter with a high voltage alternator.... There are several people doing conversions to make a voltmeter out of a ammeter, Redline comes to mind.
In the mean time disconnet the two wires at the ammeter & connect together, run a new larger wire from the alternator directly to the battery

[jforest1]

Thanks so much for pointing me in the right direction!  I should be able to figure it out from here.

JF

[tommyg29]

 
there are numerous threads in here about the "alternator bypass" or "starter relay bypass".
You do not want to upgrade the alternator without this mod first!

[MEK-Dangerfield]

Have you upgraded the wiring any? That's a heck of an increase in power. I would take the advice posted above and install a voltage gauge in place of the amp gauge.

[dodj]

It occurred to me that this may cause problems with the Ammeter.  Do I need to upgrade the ammeter as well?   
Thanks!

JF

It will cause major problems. The ammeter as wired from the factory carries the full current load of the car. (except when starting the car). It was never designed to carry anywhere close to 200amps. Voltmeter conversion would be the only way to go.

[solarguy]

http://madelectrical.com/electricaltech/amp-gauges.shtml

some good reading here

[jforest1]

http://madelectrical.com/electricaltech/amp-gauges.shtml

some good reading here

Indeed it is!

JF

[jforest1]

Indeed it is!

JF

I've got a pretty big order going MAD's way.  That was an awesome article.  I hope their book is as good, cause I'm getting one.

Okay, so from that article and the chassis manual, it looks like I need to bypass the ammeter by connecting the wires together that were previously connected to the ammeter.  This effectively allows both wires to feed into the accessories or whatever that the alternator output wire previously fed by way of the ammeter.  So there is now an orphaned ammeter and two paths to the accessories or whatever whereas there was previously one with the ammeter inline.

The alternator's output is then connected to the starter relay, which forwards on (among other things) to the two aforementioned paths.

If that's all correct, there's a couple of question marks:
1.  i must have non-standard wiring, because i currently have on my 60amp alternator a ground wire going straight to the starter relay:

Old alternator used a set of wires (red on output terminal to starter relay/positive; black also on output terminal and goes to ?ammeter?, dark green on horiz field brushing to voltage regulator, dark blue on vert field brushing to voltage regulator (and carburator solenoid)).

2.  other problem with that is with the new 1-wire alternator, doesn't the carbeurator solenoid get orphaned?  It looks like there is an "OR" in the blue wire.  What does that mean?  Seems like the ignition coil, ignition ballast, and electric choke are all tied in.

3.  how do i get to the ammeter?  Do i need to remove the dash?  if so, does anybody have a good link to steps for doing so.  i attempted to do so when I was running my remote passenger-side mirror, but stopped after I removed a lot of the plastic panels because I figured out how to run the cable without removing the dash.  I remember spending 5+ hours trying to figure out how the dash could come off and lots of fruitless internet searches before giving up.

4.  Fast forward to the future, ammeter has been bypassed successfully.  Only wire coming out of the alternator is going straight to starter relay.  Now it's time for the big-3 upgrade and to put in the new 200-amp alternator.  I've been told NOT to run the alternator 0-gauge cable through the starter relay.  Is this correct? 

5.  If so, I would NOT have to upgrade any wiring at the starter relay, provided I had the correct fusible links/etc on it and I've got the 0-gauge running out of the battery to the amplifiers well grounded, correct?

6.  In the above scenario, if my 200 amp fuse going back to the amplifiers blows, doesn't that mean all the alternator output current is flowing into the starter relay?  Wouldn't that burn of the fusible links there?

JF

[Bullitt-]

]

The alternator's output is then connected to the starter relay, which forwards on (among other things) to the two aforementioned paths.

If that's all correct, there's a couple of question marks:
1.  i must have non-standard wiring, because i currently have on my 60amp alternator a ground wire going straight to the starter relay:
The Red wire has been added, the 0-gauge you describe later will replace this

Old alternator used a set of wires (red on output terminal to starter relay/positive; black also on output terminal and goes to ?ammeter?, dark green on horiz field brushing to voltage regulator, dark blue on vert field brushing to voltage regulator (and carburator solenoid)).If your 74 is like my '73 there is a connector near the rear of the engine that you could remove these wires from to clean things up & no cutting required.

2.  other problem with that is with the new 1-wire alternator, doesn't the carbeurator solenoid get orphaned?  It looks like there is an "OR" in the blue wire.  What does that mean?  Seems like the ignition coil, ignition ballast, and electric choke are all tied in.
Not sure, possible if the OE voltage regulator was in place it could still work but since your doing all the other mods I'd just remove it, doesn't really do much anyway
3.  how do i get to the ammeter?  Do i need to remove the dash?  if so, does anybody have a good link to steps for doing so.  i attempted to do so when I was running my remote passenger-side mirror, but stopped after I removed a lot of the plastic panels because I figured out how to run the cable without removing the dash.  I remember spending 5+ hours trying to figure out how the dash could come off and lots of fruitless internet searches before giving up.
Never done it...try this link http://www.cuda-challenger.com/cc/index.php?topic=51101.msg524526#msg524526
4.  Fast forward to the future, ammeter has been bypassed successfully.  Only wire coming out of the alternator is going straight to starter relay.  Now it's time for the big-3 upgrade and to put in the new 200-amp alternator.  I've been told NOT to run the alternator 0-gauge cable through the starter relay.  Is this correct? 
I'd take it straight to the battery to avoid a bottleneck
5.  If so, I would NOT have to upgrade any wiring at the starter relay, provided I had the correct fusible links/etc on it and I've got the 0-gauge running out of the battery to the amplifiers well grounded, correct?
Must be some Huge Amps...sounds good
6.  In the above scenario, if my 200 amp fuse going back to the amplifiers blows, doesn't that mean all the alternator output current is flowing into the starter relay?  Wouldn't that burn of the fusible links there?
Nope it will only draw the necessary power...just more potential present
JF

[jforest1]

Thanks again Bullitt-!!!

5.  Must be some Huge Amps...sounds good
6.  Nope it will only draw the necessary power...just more potential present

5.  Yes. 
http://www.cuda-challenger.com/cc/index.php?topic=75961
for:
http://www.cuda-challenger.com/cc/index.php?topic=75619.0

6.  Thanks.  For anybody else reading this that would like to understand WHY that is the case, here's an awesome read:
http://madelectrical.com/electricaltech/howitworks.shtml

JF

[jforest1]

I've connected W together, bypassing the Ammeter.
I think I'm confused about Z--misreading the wiring diagrams or something.
When I replace the 60A 3-wire alternator with the 200A 1-wire alternator, I lose the X and Y wires, which go to the Voltage Regulator.  Also connected to the field brush is the carb solenoid, electronic ignition control, and ignition ballast.  What do I do with them?


JF

[Bullitt-]

IF "Z" is the alternator output you would go straight to the battery, it appears you have it going in past the fusible link.
 Is the rectangle in the lower left the battery?
The Blue wire (XorY whichever is Blue) that goes to the ignition parts should be left as is.

[jforest1]

IF "Z" is the alternator output you would go straight to the battery, it appears you have it going in past the fusible link.
 Is the rectangle in the lower left the battery?
The Blue wire (XorY whichever is Blue) that goes to the ignition parts should be left as is.

I haven't confirmed Z exists in reality yet, this is my takeaway from the wiring diagrams.  The 'I' looking blocks are actually the bulkhead disconnects (labeled BD).

I cannot really leave Y (Dark Blue) as is because the new alternator has no field brushes--it's a 1-wire alternator.


Excuse my writing, this was (believe it or not), the second, cleaner version of the diagram.

JF