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Ammeter to voltage meter.

Discussion in 'The Hokey Ass Message Board' started by Cabbie, Sep 1, 2012.

  1. BJR
    Joined: Mar 11, 2005
    Posts: 7,242


    That is what I did with my 49 Buick. I found a volt gauge that would fit into the cluster in place of the amp meter. The cluster still says amps but I know it is reading volts.
  2. donsz
    Joined: Nov 23, 2010
    Posts: 223


    I still have the stock ammeter (shunted) in my 1957 truck. It uses an 100 amp alternator. Never had a problem. In my opinion and experience, properly installed, safety is not an issue (although the ammeter wire is heavier guage than the other instrument wires, so I can see why some might have a concern). I know there is much debate on this, but I prefer the ammeter, it tells me right away if the system is charging or discharging. Each to his own. Now I am going outside and look for any pre-1955 vehicles passing by.
    clunker likes this.
  3. arkiehotrods
    Joined: Mar 9, 2006
    Posts: 6,604


    My '66 Caprice with factory console gauges had an ammeter. A vacuum gauge, too.
  4. Exactly. Ammeter is as useful as a voltmeter. Both give different info. Ammeter will tell you if the cut out relay points in an old regulator get stuck closed after your car is off, or if your generator is putting out too much/little current. One that uses a shunt and a fuse before the meter is a lot safer. Only a small percentage of the current is going into the cabin.

    Volt meter tells you if cut out relay isn’t closing, if voltage regulator isn’t working right, or your generator or battery is fried.

    Sent from my iPhone using The H.A.M.B. mobile app
  5. jack_pine
    Joined: Jan 20, 2007
    Posts: 352

    from Motor City

    Old thread but I wanted to share some experience: Dodge trucks are particularly vulnerable to problems associated with "all the current through the ammeter" problem because the junction block at the firewall gets crusty, corroded and melted over years of high-current loads such as: running a winch, a snowplow, etc. All the current for those loads comes through the ammeter; unless very unusual steps were taken to avoid it.

    Anyway...years of decay causes voltage drop so....dash lights are dim, headlights are dim, yer fancy Pertronix deal runs a few volts low to the coil, etc....

    THE FIX: we Sweptlinesmen have learned to route alternator output direct to the battery. Everything brightens right up. For the former feed into the cab, take the line that runs into the cab and run it through a fuse right to the battery.

    Here are two wiring diagrams for reference:

    DODGE SAID SO: in FSM, they describe "heavy duty wiring" which basically did the same change as outlined in the above diagrams for Camper Special and Police packages.

    Ammeter: mine stays in the dash. It's dead. I install a voltmeter. It tells me if the charging system is working because I see 14+ volts...healthy!

    On my A100 van, I had the ammeter converted.

    Attached pic: my wife checking out my butt while I am trying to do the wiring conversion by the side of the road. Truck would not re start after roadside stop. Battery dead. Ammeter was in the middle since the truck has no options...running off the battery didn't look much different than "fully charged" on the ammeter. Battery was still at 12.x volts but didn't have reserve to crank the starter. 20200614_205604.jpeg

    Sent from my SM-G892A using The H.A.M.B. mobile app
  6. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 2,593


    Pontiac used a gauge similar to a amp probe.. They called it a "Battery" gauge.. This was one of the best set ups for checking the charging system I ever saw.
  7. Work In Progress
    Joined: Dec 14, 2010
    Posts: 167

    Work In Progress

    After I installed a 70 amp alternator, I figured my ammeter's days were numbered. Here is how I installed a volt meter guts were my ammeter used to live.
    Original ammeter
    ammeter 1.JPG
    New voltmeter installed, never mind the mismatched screws It was that way when I took it out...
    ammeter 2.JPG
    Another shot
    ammeter 3.JPG
    Old needle epoxied on
    ammeter 4.JPG
    A little paint work... When the needle is straight down it's battery voltage. Anywhere to the left, it's charging.
    ammeter 5.JPG

    Attached Files:

    Charlville likes this.

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