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replacing ammeter with a volt meter?

Posted By: NEVjr

replacing ammeter with a volt meter? - 09/30/14 12:16 AM

i am looking to upgrade the alternator on my 62 valiant, and i would like to make the ammeter into a volt meter.

i am an electrician by trade and i understand the theory of both types of meters, and i know how to do the conversion on a portable analog ammeter, but i am baffled by the spare ammeter i have in front of me, it seems to have no coil, and the shunt is the aluminium gauge face?

i would like to keep the original gauge, is there a conversion kit or anything available?

thanks
Posted By: Cudajon

Re: replacing ammeter with a volt meter? - 09/30/14 01:34 AM

Amp to volts Try this, see if it helps.
Posted By: NEVjr

Re: replacing ammeter with a volt meter? - 09/30/14 03:38 AM

that is a pretty good solution if you ask me
Posted By: ahy

Re: replacing ammeter with a volt meter? - 09/30/14 05:38 AM

Two basic approaches I know of. 1) Pull the guts of an aftermarket voltmeter and install in your cluster 2) Have gauge shop do it (and silkscreen the volt markings).

Both can work... I did the latter and it works great. MA had an article on the DIY method... maybe check back issues.
Posted By: Cab_Burge

Re: replacing ammeter with a volt meter? - 09/30/14 08:32 AM

Does all the amps from the alternator go through the amp gauge like it does on the later Mopar cars? If so that needs to be addressed to safely get the current back to the battery, correct? I recently added a 100 amp alternator to my race car that didn't have a charging system on it when I got it so I used a 8 gauge wire ran directly from the alternator output to the positive post on one of the batterys so the car would not run when the battery cut off switch was turned off. I ran a 18 guage,I think, through the main ignition switch to the voltmeter so I can see if the alternator is working or not when the engine is running. I had a old race car that a guy bought and added a voltmeter in series to the battery in the trunk with no cut off switch or activation switch, it would run the battery dead in a couple of days, it wasn't digital. All electrical gauges use current to run them, correct
Posted By: dodgy

Re: replacing ammeter with a volt meter? - 09/30/14 11:48 AM

like others I changed my system to volt meter, moded the dash and fitted a volt meter, got the local sticker mob to make me up an overlay.


have a few left but I'd say they would be different to your dash.
Posted By: NEVjr

Re: replacing ammeter with a volt meter? - 09/30/14 01:54 PM

it does go through the ammeter in the dash on #10 wire like later cars

my dash is orange needles over brushed aluminium with black markings
Posted By: Cab_Burge

Re: replacing ammeter with a volt meter? - 09/30/14 06:06 PM

Quote:

it does go through the ammeter in the dash on #10 wire like later cars

my dash is orange needles over brushed aluminium with black markings

You have two choices, splice or replace those leads If your going to keep a stock Mopar low amp alternator splicing with solder may be a good choice If your going to hop up the alternator(80+ amps or or more) maybe replacing the stock wires for bigger wires ran direct to the battery may be a better choice Good luck either way
Posted By: NEVjr

Re: replacing ammeter with a volt meter? - 10/01/14 12:16 AM

i have some nice big #4 welder cable to go direct to the battery, i want to pick up a better alternator, maybe 80 or 100A, the stock one wont run all the accessories at once according to the ammeter, (heater fan, headlights, wipers)
Posted By: Cab_Burge

Re: replacing ammeter with a volt meter? - 10/01/14 12:47 AM

I used a 10 ft. piece of #8 wire on my race car with the 100 amp alternator. There is not a huge load on the charging system when racing it, maybe 35 amps total On the splicing I should have mentioned splicng the two wires behind the amp meter in the former post, replacing it is a better deal with anything over 45 amps load I might consider a # 6 if it is from the front of the car to a battery in the trunk, if the run is less than 10 ft I would probally go with #8 or #10 . I think Powermaster, Tuff Stuff or one of the other aftermarket alternator companys has a chart with lemgth, load and wire gauge sizes recommended for there bigger alternators
Posted By: ahy

Re: replacing ammeter with a volt meter? - 10/01/14 12:56 AM

In general, the later mid/late 70's square back is a lot stronger than an early 60's round back and will bolt right in. The factory rated them up to 78 amps. You could get a reman at the parts store but I wouldn't recommend it as quality is not good on the ancient cores. I'd go with a Powermaster usually rated 75 amps.

The late style square back will make 50 amps or a bit better idle output. Plenty with near stock accessories. If your future includes electric fan, big electric pump or massive sound system not enough.

The later alternator with two voltage regulator terminals will work with the 60's style single wire regulator. Just hook the original regulator wire to one terminal and ground the other with a jumper. Doesn't matter which is which.

Good luck!
Posted By: Supercuda

Re: replacing ammeter with a volt meter? - 10/01/14 01:30 AM

You realize the battery is only a part time load on the alternator, once it's charged back up it is no longer a load. The rest of the system is the load, so running big wires to the battery doesn't fix the issue just masks it as the ammeter does not measure output from the alternator to the rest of the system, just to/from the battery.

If you truly have large electrical loads you should run them via relays directly sourced from the alternator output.
Posted By: NEVjr

Re: replacing ammeter with a volt meter? - 10/02/14 01:16 AM

i dont plan to use the #4 because of load, i plan to use it because its around, and i dont have any big loads planned, just basics like maybe a fan and fuel pump, third brake light and the controller for a gear vendors unit. EFI is in the cards as well, and i dont want to worry about putting the car in neutral at every stop light on a rainy night to keep the alternator charging

sound system is going to be a 10w bluetooth amp and speaker set up hidden in the dash behind the original speaker grille, so i can hear my music over the road noise, i can buy a modern car if i want modern distractions
Posted By: GeorgeH

Re: replacing ammeter with a volt meter? - 10/02/14 08:41 AM

Quote:

You realize the battery is only a part time load on the alternator, once it's charged back up it is no longer a load. The rest of the system is the load, so running big wires to the battery doesn't fix the issue just masks it as the ammeter does not measure output from the alternator to the rest of the system, just to/from the battery.

If you truly have large electrical loads you should run them via relays directly sourced from the alternator output.



I'm assuming something like what is like the wiring diagrams on the Mad Electrical website? Where the alt feeds the fuse box directly and the regulator is sensing volts at the fuse box? Supposedly more stable voltage throughout the system.
The info i'm looking at is on www.madelectrical.com and its towards the bottom of their tech page " bypassing amp gauge".
If anyone has tried these mods chime in please.
Posted By: BulletBob

Re: replacing ammeter with a volt meter? - 10/02/14 09:23 PM

Quote:

like others I changed my system to volt meter, moded the dash and fitted a volt meter, got the local sticker mob to make me up an overlay.


have a few left but I'd say they would be different to your dash.



I do all my Amp to volt changeovers like that Harbor Freight sells a small diameter one that I put in 72-80 Dodge trucks
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