amp meter to volt meter conversion

[68gtx]

have read that our factory amp meters are a risky thing to have, can cuase dash fires and people were converting them to volt meters to get rid of the risk. anyone know hoe to do this?

 

[HT413]

Search the forums. One of the guys posted a step by step process where he modified and fitted an aftermarket voltmeter in the ammeter's place. Looks and works great.

 

[67 coronet]

easyest way is to disconnect the wires going to the back of the amp meter and hook them together.as far as the volt meter,you just need a 12 volt source that is activated with the ign switch and a good ground.(volt meter should come with directions for wiring)thats all you really need.

 

[ChgrSteve67]

Converting is easy. Just take the wires loose from the Amp gauge and connect them together.

I took a insulated ring, connected a wire to it then connected all three wires together with a small bolt and nut. I covered the bolt and wires with some heat shrink tubing I slipped on before connecting the wires.

Then you just connect one side of the volt meter to the new wire and the other side to ground.

As far as the gauge to use some have found replacement gauges that can fit in the dash, some have replace all of the gauges so they all look the same, others have found a place to locate the new gauge and left the factory amp gauge in the dash.

Last note: Some like to take voltage reading closer to the battery vs. the stock amp meter location. I find the stock amp meter location works for me and is easy to wire without having to modify the wiring harness.

 

[440roadrunner]

Read this excellent article which gives a how to as well as the why and the "whut happens:"

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

You should do more than simply jumper the ammeter wires, that really changes NOTHING.

What you need to do, if you do that at all, is also run a nice big direct feed from the alternator output to the starter relay battery stud. Depending on how big your alternator is, this could be anywhere from no10 and larger. If you cannot easily get no8 or no6 wire, you can also make the alternator to relay jumper out of two parallel no10 wires.

 

[Propwash]

Here's a voltmeter conversion post I have on my RR resto. Hopefully it helps. I took the two wires of the back ammeter and soldered them together, then heat shrink over the top of that. I also drilled out the bulkhead connector so that the main fusible link wire coming in off the starter relay no longer has the male/female connection. Just a solid wire running through. Key on +12V off the fuse block and a solid ground, voltmeter works great.

So I said I would post on the ammeter to Voltmeter conversion, so here they are....

Just to recap just a bit, I'm going this route because I'm going to a powermaster 140 one wire alternator as well as I don't want to sit and worry about this car going up in smoke


First off a couple pieces of the old ammeter....Pretty nuts isn't it?? This car had a 50 amp alternator when I pulled it out (nothing special), and who knows how close this came to lighting the dash up in flames.

Check out the heat affected zone on this....Obviously this metal got pretty hot!

Got a little a head of myself before pulling out the camera, but this is the Sunpro 2" Voltmeter (P/N CP8205), with it's guts ripped. To pull out the old meter, take off the two pal nuts for the fuel gauge (face plate overlaps the face plate for the ammeter), then take off the nuts for the ammeter..walla!
you'll need to drill out two very small rivets to seperate the factory faceplate from the ammeter. I used a cutting wheel to cut slots in the voltmeter case. Made the sealed unit come apart real easy.

The center to center holes n the back of the cluster assembly are further apart than the sunpro studs, but the voltmeters studs are smaller so they slide right down in the holes..

Being the studs of the volmeter ride real close to the inside of the cluster housing holes, I covered a good chunk of the studs with heat shrink as well as liquid electrical tape on the transition just to make sure there is no chance it can arc to the housing

I cut the original shorter needle off the sunpro at its base, cut the old one of the factory ammeter and used some JB Kwik Weld to secure in place on the new meter.
I also had to trim down a little finger on the plastic meter housing about an 1/8" of an inch which is used to hold the original sunpro face plate from sitting on the electrical wiring/solder on the unit. Makes the mopar faceplate stick out a bit too far.

I had to do some trimming on the original faceplate with a dremel to fit the meter in correctly. One this meter is secured from the backside, it doesn't budge so I didn't secure in any other manner from the inside. Also the face place is overlaped by the fuel gauge faceplate, so that hold it in place as well.

Here's how she looks with the cluster lense installed...You cannot notice any kind of modifications from the outside..The need can be adjusted for a different starting point by just turning a little cam on the backside of the magnet on the guage. The needle right now sits a bit higher than the other bottomed out gauges. Not really that noticable at all.

This is at 12.75 volts...Like I mentioned you can adjust the needle starting point on the voltmeter... I set mine up to read like this being the powermaster puts out a regulated 13.2 volts and that should center the needle in the gauge. Also being the studs are a bit undersized for the holes, you can twist the unit one way or another when loosing it up from the backside and tweek the needle to meet center if need be

Here's the back...The heat shrink runs right up to the top of the nut. It also slides through the through wall grommets in the bracket, thus no arc's. The bracket came with the voltmeter for securing the gauge in a housing, I just cut off the ends. I'll probably dabble on some liquid electical tape on the bracket around the washers as well. Like mentioned, the through wall grommets work great for protecting a short.. I'll run another nut on top and a star washer to secure the wires.

A good idea to do on the backside is write on a + and -, being the positive is opposite what the factory has stamped on the back of the case. I also indicated the change over seeing you never know if the car may fall in someone eles hands someday.. I will take the two original wires that use to run to the ammeter, solder them together and heat shrink over. I also plan on drilling out the male/female connection in the bulhead for the wire coming in, run the wire straight through, solder together and heat shrink install a inline fuse.

So there it is.......If you were thinking about spending the $150-$200 after shipping with Redline (nothing against them), here's another option where you'll spend about $17 bucks on the voltmeter and maybe an hour or two depending on your skill level. I know for me this really gives me a good piece of mind I don't have to worry about any issues in that area any more. Hope it helps some one out someday....

 

[YY1]

Nice writeup and nice accompanying photos.

 

[440roadrunner]

That's great but why is your alternator only putting out 13.2? That is WAY low, should be more like 13.8--14.2, and in no case below 13.5, or did you mistype??

Here's some more ideas from FABO

My 67 dart is similar to the dash above, but other end of the cluster. Mine is adjusted so the old center scale is 14V

http://www.forabodiesonly.com/mopar/showthread.php?t=119480

 

[Propwash]

I set my gauge at 13.2V The Powermaster 140A im going with is a single wire/internally regulated (GM Style) Alternator. Pretty sure I finally have the mounting squared away. I went off the P.M. spec to set my gauge.

Chrysler Alternators
75A Specifications
45A @ 2,400 RPM @ 13.2 VDC @ 77F
Operating Range: -40C to 150C
Maximum RPM: 16,000
140A Specifications
80A @ 2,400 RPM @ 13.2 VDC @ 77F
Operating Range: -40C to 150C
Maximum RPM: 18,000
170A Specifications
110A @ 2,400 RPM @ 13.2 VDC @ 77F
Operating Range: -40C to 150C
Maximum RPM: 18,000

 

[440roadrunner]

I don't understand where you / they are getting 13.2. That is on the low side. In other words it should not be the TARGET setting, it should be the low side of a range

Here, a clip from the 67 , and below that, the 72 Chrysler shop manual:

 

[Propwash]

Again, this is a powermaster 140Amp one wire internally regulated GM Style alternator, not anything from chrysler or comparative to chrysler alternator specifications. As far as where they are getting their results, I imagine from their own independent product line tests. If you would like to further investigate their product line specifications, I would recommend visiting their site or give them a call.

 

[440roadrunner]

I may do that. What you need to realize is that it doesn't MATTER who made the thing. Lead acid batteries need the same charging voltage whether they are in Mopars, Fords or my Farmall tractor.

 

[Propwash]

Hey, I took the time to add to this post so maybe someone could use it down the road, stating facts as well as real information from a vendors site.

Again, those are factoral specifications from Powermaster, not some conjoured up little chart I made up for my own health. It's 13.2V at 2400RPM. With a 3:1 Ratio, that's roughly 800RPM on the engine side. So, around idle, the volt gauge should center. Now, if you want to call their tech department and have a pissing match
with their engineering department about the basics of automotive charging/regulation parameters, go for it.

As far as you statement about the same charging voltage, I don't know where you are going with that. Obviously batteries must have a maintained voltage which is regulated by the voltage regulator. My 13.2 volts at idle compared to the older 12V generator systems (that ran lead acid batteries), is 10 steps ahead of the 8...9 volts some systems would run at idle.

Now, if you want to further research this, make calls, write a book...I really don't care. I bought and own the product, and will be installing it on my car

 

[440roadrunner]

Methinks you are the one starting a pissing match. 13.8--14.2 has been the defacto default standard for lead acid batteries. I has nothing to do with who engineered what. It has nothing to do with who wants to be "right." You can't read the info posted right out of a Chrysler manual? must I also go find a Ferd/ GM manual and post that too?

Worse, you are arguing like a woman, making things up out of the blue sky. I didn't "make" those charts. They came right out of a Chrysler shop manual. Look 'em up. SURELY a smart guy like YOU has a Chrysler shop manual? Go get some sleep. You are either drunk or overly tired and are not thinking clearly.

Some light reading

http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

or

http://www.w8ji.com/battery_and_charging_system.htm

even wiki:

http://en.wikipedia.org/wiki/Automotive_battery

 

[Propwash]

Wow....some people really are this dense. I guess it's no news flash. Arguing with a woman? LOL Well, you could be on my end and be arguing with a someone with a childs mentality. Yes I can read chyrsler's shop manual, but again...and please read s..l..o..w..l..y.....this is not a chrysler product! That makes two times i've told you that. It's not a '67 or '72 chrysler. Not a Ford, not a GM. A GM Style alternator, engineered and built by powermaster. 40 year old shop manuals have nothing to do with it...Understand? I never said you posted anything out of the "blue sky"..I wasn't trying to imply you created the mopar spec's. You read the post wrong. The info I posted is a specification sheet from Powermaster, easily accessible by anyone on the internet. And yes, I have several service manuals..thanks for asking.

No, not drunk, not tired, but simply in awww I've wasted more of my precious time on this planet with you and your antics. Now I guess could sit here a take cheap shots like you or google 30 links that show the chart I posted, but that would lower me down to your unhappy little level. So, call Powermaster....go waste their time. Hope it works out well for you.

 

[Revhendo]

Hey Will, thanks for the post and the pics. I gotta lil project I was looking at doing this on and you answered some questions I had.

And just so I have it right....
If my voltage reading is low, I can just turn the needle up?

 

[Propwash]

No problem Rev. Glad it could get some questions answered for you. As far as setting the needle, you really can't see it in any of the pic's but the needle is connected to a magnet on a shaft. On the front side of that there is a very small flat plate secured in place by a couple very small dabs of adhesive (very easy to break the bond). Free that plate and it turns one way or the other. Moving that plate will allow you to set the start point where the needle rests when not powered. You can tweak that start point so that the needle will sit centered at a desired voltage.

Hope it helps.

 

[Revhendo]

No problem Rev. Glad it could get some questions answered for you. As far as setting the needle, you really can't see it in any of the pic's but the needle is connected to a magnet on a shaft. On the front side of that there is a very small flat plate secured in place by a couple very small dabs of adhesive (very easy to break the bond). Free that plate and it turns one way or the other. Moving that plate will allow you to set the start point where the needle rests when not powered. You can tweak that start point so that the needle will sit centered at a desired voltage.

Hope it helps.

It does and I actually bookmarked it.

It's also good to know I can adjust my idle voltage up from that dismal 13.2v by simply moving the needle.:grin:

 

[Lowhound]

Good information Propwash. Good explanations too.

 

[Propwash]

It does and I actually bookmarked it.

It's also good to know I can adjust my idle voltage up from that dismal 13.2v by simply moving the needle.:grin:

LOL........touche Rev!