Turn ammeter into a voltmeter?

[MJS73]

So let's see if I have this straight.  Butt-connect the existing black and red wires that used to go to the ammeter.  Run one wire from the new voltmeter to a switched power source (radio?) and one from the new voltmeter to ground.  Do I have it?

Mike

[MJS73]

I just got off the phone with RLG, it turns out that they internally wire for the voltmeter when they do the conversion, so all that has to be done is connect the (now) disconnected red and black ammeter leads and tuck them out of the way.  No new connections are needed at the voltmeter.

Mike

[LAA66]

 Sounds like a nice, easy swap to a voltmeter. Please let us know how it works out. I have been to lazy to take the dash apart (again), maybe this will provide some motivation.

[71 DEPUTY]

use the dark blue wire that feeds the ing. system to the engine- it's the same power source that the alt's reg. gets it's power for a more accurate voltage reading. radio would work- but it is on a fused circuit- if it blows you don't know what is happing!!!! ( I would use a 1 amp fuse to the volt meter just to protect it as the dark blue wire is full power with only the fusable link to protect it!! )

John Mac

[LAA66]

 I agree, the flow directly from the alterator would be the best indicator of the voltage being produced.  These guys must have that incorporated in the install.

[nivvy]

So let's see if I have this straight.  Butt-connect the existing black and red wires that used to go to the ammeter.  Run one wire from the new voltmeter to a switched power source (radio?) and one from the new voltmeter to ground.  Do I have it?

Mike

thats what me and MEK said earlier... works fine 

[LAA66]

 If the feed doesn't come directly from the source there would probably be other draws such as headlights that skew the meter reading. Not that it really matters as long as the system is reading positive.   

[BruteForce]

I just got off the phone with RLG, it turns out that they internally wire for the voltmeter when they do the conversion, so all that has to be done is connect the (now) disconnected red and black ammeter leads and tuck them out of the way.  No new connections are needed at the voltmeter.

Yes, it seems that all one needs to do is attach the voltmeter to the 12V input to the voltage regulator mounted to the back of the dash panel (the one that converts 12V to 5V for the other gauges).

[BruteForce]

 

I agree, the flow directly from the alterator would be the best indicator of the voltage being produced.

If the voltage in the supply circuits behind the dash are measurably different from that at the alternator, you've got an electrical problem, likely one of:

1) undersized wires for the current flowing through them

2) corroded/dirty connectors

3) miswired components

4) frayed wires hanging on by a single strand

5) a short or near short somewhere

6) bad ground connection

You can track it down by measuring the voltage at various points in the circuit till you find the spot where it drops.

[MJS73]

Yes, it seems that all one needs to do is attach the voltmeter to the 12V input to the voltage regulator mounted to the back of the dash panel (the one that converts 12V to 5V for the other gauges).

Actually, they said that they make that connection for you, so no connections need to be made by the user.

Mike

[duodec]

Is there any source for small inductive type (clamp) ammeters, like an Amprobe but small enough to use in the dash?  It might be possible to disassemble one of the tool-type units and use the mechanicals to drive the ammeter pointer while the clamp surrounds the joined wire now bypassing the gauge.

I know voltmeters are more useful, and I also know I won't be able to safely run the ancient ammeter in my Challenger given some of the electrical upgrades, but I'd really prefer to keep the stock functionality if possible.

Found this one on Ebay; its unidirectional but otherwise what I'm looking for.  Anyone make a bidirectional?  Seems like it would be popular for solar-addon systems where you could monitor net flow in either direction...

http://cgi.ebay.com/Solar-Generator-Power-Monitoring-Meter-Ammeter-NEW_W0QQitemZ200190320478QQihZ010QQcategoryZ3240QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[BruteForce]

If you wrap wire into a coil around the main battery wire, the current going through the battery wire will induce a dc voltage in the coil. This can be connected to a voltmeter, and when calibrated, will safely show the amps running through the battery wire.

[BruteForce]

If you wrap wire into a coil around the main battery wire, the current going through the battery wire will induce a dc voltage in the coil.

What was I thinking? That statement is not true. Only a changing current will generate a voltage.

[LAA66]

 I was lost when y'all said electrical problem. 

[wunderless]

I made the switch this year. 
Works well, once i figured out that you have to connect the wires together that ran to the ammeter.
Man that was annoying, cause I did it all in dash too.  It's hard to reach up there.