[Guest]

Since the RC ammeter is useless.... I am trying to substitute a 12 Volt.... digital volt meter...

The 1st digital voltmeter was installed in place of the ammeter.. I ran it outside the old schematic design re the ammeter..
I feed it power from the (under the steering column) wiring connector that carries the circuit for "Hot In Run Only" .. I say it operated for about  an hour maximum.. while I checked other circuits to begin final hook ups re dome light etc etc.

SO now this newly installed digital gauge suddenly quits..a check of the circuit from source to the back up to the gauge shows hot..and the other side black wire..  is correctly grounded..  I am wondering if this digital volt meter became "fried"  by too many amps from the Alternator...?  Since it gets unfused raw power from the battery which in turn ...gets fresh power direct from the alternator..   

  I will run the power to the new digital volt meter No# 2  through either an in-line fuse holder re 10 or 15 amp fuse or through an unused fuse in the fuse box provided it's a "hot in run only"..feed.  I sent a message asking the on-line auction... vendor what the maximum amps this digital volt meter can carry.  Will see wht reply I get. 

If above plan A fails, Plan B, is to install the analog gauge.. see pic...  Plan C, will be to buy a combined Digital  Volt meter / Ammeter gauge.    I am thinking that any dual function digital ....like the ones I saw from 12V to 24V will have the same equivalent on the amp side.. enough to handle any that the RC alternator could possibly spike, short of the RC getting hit by lightning.. 
Since I'm in FL that's only a partial joke..      Will post my progress..
Ed K

 

[SuperBurban]

I replied in  the other post, but will repeat here.

The voltmeter should not have anything between the power source (besides switches), and the ground. It should only draw the power it needs to run, if fused, I would run only an amp or two. If you have a multimeter, many have a way to measure small currents, and you could measure how many amps it actually draws.

I suspect it died from run of the luck bad unit, rather then something from your engine. unless the alt, is putting out spikes, but that would be buffered by the battery, so they should not be more then a few volts.

Regarding the analog voltmeter, that particular one, and most, are designed more for stationary use, and the needle will bounce like crazy as you drive.

 

[SuperBurban]

The two terminals from the old ammeter, are not hot, and ground. They are battery, and load/ charge. Pretty much both hot. Best to do it like you did, with bringing the wires out, and hooked up separate from the cluster. Alternatively, you could have used one of the ammeter terminals for the hot, and ground brought out like you did, or attach to a ground circuit on the cluster (one side of the gauge lights should be ground).4

Looks good.  Now I gotta get my rear going, and do mine, I've only been sitting on the meter for a few years.

 

[Guest]

    2nd Attempt...
I used another original ammeter face on this 2nd attempt. If you don’t have one a thin sheet of tin trimmed out will do. I took more time to cut the four sides of the “window” more carefully.  I ruined the first ammeter face by moving too fast. The second attempt I took a lot of time to allow room for error around all four sides. As I worked my way out to the final shape of the “window” I test fit the digital module behind the opening to keep checking that no edges were lopsided. I traced the outline of the exact area of the digital readout, marked it and gradually worked my way out to each edge using the face of the dremel cutting disk, (not the thin edge) eventually I got a good even rectangular opening. I used the lower part of the cutting disk so the metal fragments / disk particles would be cut and thrown downward not up into my face-eyes. Remember to use a high quality mask and eye protection. I used a NIOSH N95 surgical type mask covering my nose / mouth and ample eye protection.  Then,  sprayed several thin coats of flat black paint to cover the old ammeter white markings, leaving time for each coat to dry. Next.. on the rear of the old ammeter face plate are the electric parts of the old ammeter gauge. I removed them using needle nose pliers & small metal cutting pliers. I used a dremel to carve away just enough of the old gauge support base to mount- support the new digital module.  I glued it using a little Goop, on the left and right side and top, then held it in place using plastic clamps to gently hold the digital flush up tight against the back of the face plate until the Goop dried. 
To install the “digital” gauge back into the cluster housing, I used the two threaded studs of the old ammeter to mount it exactly where the old ammeter was. I used a soldering iron to melt a hole in the underside of the cluster housing to route the two wires from the digital out that way instead of going near the old printed circuit board on the back of the cluster. I then connected the red (power) lead from the new digital voltmeter to the fuse box, using an unused fuse cavity. This fuse got power by connecting it to a "Hot in Run" circuit …I found it by checking the factory service manual electrical schematic for the year of my truck. I double checked it also using a probe to positively determine that the intended circuit would be powered up when the engine is running "Hot In Run Mode" only. The black lead, I attached to a good metal chassis ground. If you don’t feel qualified an auto/truck electric shop can do this....  P.S.  Another way to monitor voltage might be the following..  On searching that on-line auction, I observed volt meters that plug into a cigarette lighter port which is also seems like a decent solution.