Standard Gauge Cluster Ammeter to Volt Meter conversion video

[JunkYardFind]

Finally finished the video that shows my Ammeter conversion to a Volt meter! It's pretty cool, the conversion turned out great! Check it out here on our JunkYard TV YouTube channel ....

 

[72RoadRunnerGTX]

Nicely produced video but there are some serious points of contention stated here. I fear you are only perpetuating the “Ticking Time Bomb” Mopar ammeter myth. I see a perfectly good ammeter being cannibalized for an instrument providing far less useful information about charging system real time health. Not seeing any signs of any heat damage to the main ammeter bus, connection studs or insulators from loose or poor connections. All of the vehicle loads-alternator output does NOT flow through the ammeter as originally designed, only the battery charging/discharging current should be registered. With a fully charged healthy battery, heathy charging system, no added aftermarket loads connected directly to the battery, there will be little to zero current flowing through the ammeter and related connections. Ammeters don’t cause problems, poor/loose connections, over tightened stud nuts, excessive moisture exposure and general lack of understanding of the function of the ammeter cause problems at the ammeter connections.

A lot of folks like to refer to the “Mad Electrical article” when doing or promoting an ammeter by-pass, voltmeter conversion. I would suggest another read through, note it was specially addressing the late seventies Dodge truck “plastic” ammeter melting issue. The passenger car ammeters from the sixties and seventies a not constructed with plastic framing, they will handle a great deal of current with clean connections and a little care. While some of their opening assertions are flat out wrong, there are other “by-pass” suggestions in the article there I agree with, bulkhead Packard connectors in the charging circuit for example. Address the Molex connections at the ignition switch as well. In my experience, do that before by-passing a perfectly good ammeter.

 

[MoparCarGuy]

Now we need the same conversion for the Rallye Instrument Cluster.
There is a thread showing pictures using the SunPro CP7985 voltmeter gauge modified to fit.
I added another picture showing a similar conversion of same mod. Requires blacking out area behind faces to hide potmetal silver finish.

 

[Challenger RTA]

All of the vehicle loads-alternator output does NOT flow through the ammeter as originally designed, only the battery charging/discharging current should be registered

As GTX said above is correct.The amp gauge is not the problem. In a perfect world I would keep the amp gauge. No loose,corroded or overloaded connections any where.
That's not what I did.
In short. I opted for the volt gauge and the charging bypass. Used the alternator feed bulkhead connector to feed the load from the battery and left the battery changing wire in place as it was. Then connected other loads to the battery ( Headlight relay and others). Electrically the same as connected to the alternator. Alternator connected to battery in bypass.

Instead of posting a 1000 word I'll post pictures that explain a 1000 words for now.

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[72RoadRunnerGTX]

Not a fan of these conversions, at least a pristine E-body Rallye cluster ammeter wasn’t cannibalized for another one of these voltmeter conversions. Did that ammeter find a good home? Would have liked to have had one like that for my current E-body project.

 

[MoparCarGuy]

I am in the ammeter-to-voltmeter conversion process now on a Rallye cluster (Cuda) along with a solid-state Instrument Voltage Regulator (IVR) from Real-Time-Engineering.

I also used the SunPro CP7985 Voltmeter. Cut down the aluminum face and relocated it upward which requires cutting the area where the needle sweeps for more clearance plus drilling two new holes in the face for the screws. Also, unsoldered, relocated, and resoldered the diode and resistor combo so it was more compact (won't short out on the bottom of the gauge housing).

The SunPro needle was shortened, made more pointy, and then painted with Testors Orange Fluorescent RM11731 paint. Ordered the Testors Fluorescent Paint Kit (9132X with Barcode 75611 91320) to get the paint. Painted needle with three coats of Orange. Note: Some have said that the Testors Red Fluorescent RM11751 matched but it was too red for my gauge needles to match it (almost the same as the SunPro color).

I will post the final assembled results soon.

 

[MoparCarGuy]

Wrapped up the installation of the voltmeter in the gauge cluster today. Verified with a multimeter (Ω) that the posts were isolated from the gauge housing. It would have been okay if the NEG side post (toward the 8 Volt side of the scale) was grounded since that needs to be grounded anyway. Also, powered up the gauge afterward with a variable DC power supply. Need the needle color to be closer but after everything is back in the car it will be good enough.