So I have my just completed top bottom restore 46 dash sitting on my bench next to my new American Wire - wire kit. A buddy of mine stopped by with his friend who wires off road cars on the side. He was looking at the dash and said Surely your not going to run that amp gauge are you? That wire that go's through the gauge is hot all the time and I have seen it start more fires than any other device. I Said Damn, I've been running them just like Ford did for years without a problem. Have any of you guy's heard this before?
Yes, it happens, but done properly, with the right size wire and good connections, it will be no problem. Chrysler also did it for years. Bones
1959 Ford F250, previous owner moved the wiring to an aftermarket underdash ammeter, a common modification back in the day. The ammeter shorted internally and started shooting sparks while I was driving down the road. Fortunately, it was a case short and melted back the cars before the wire insulation melted. Common causes are ammeter short (the original ammeter has ancient insulation and some aftermarket ammeters are cheaply made, even before the manufacture was off shored to the Peoples Republic of Tinpanistan. If the alternator develops a short, the battery drains thru the main wiring harness, creating a big melted mess. In a somewhat OT IH 3/4 ton pickup, had a wiring short burn several wires together in the main wiring harness. It was a pain working under the dash. For the last 30+ years, the ammeter is bypassed and a Voltmeter is added.
It depends.... If it's the type that has no direct wire connection to the gauge but merely passes the wire through a metal 'loop' on the back of the gauge, you'll be fine. If it is a direct connection, you may still be OK as long as you're still running a OEM generator. Where guys get into trouble is upgrading the charging system with a bigger-amp alternator that can put out more current than the gauge is designed to measure. That will get you a fire.... Also keep in mind these things do fail on occasion... And with an alternator upgrade and the 'loop' style gauge, it may kill the gauge, but there shouldn't be a fire hazard. If you're running an alternator that puts out 60 or more amps, you really should use a voltmeter instead.
They also start fires when the load you put on them is a lot higher than what they are designed to handle and that is most often the issue. If the car has very limited accessories and you run anything that draws any real power through a relay that is connected directly to the battery (though appropriate junction block and what not) rather than running though the amp gauge you should be ok. That is AC if you run it or Halogen headlights or an amp or other high power draw units.
I'll also point out that which type of system you have will make a difference in the gauge. Alternators and generators don't output the same way because of their design differences. An ammeter is a better choice on a generator because a generator will do a better job of maintaining voltage even if it's struggling to meet current needs, a voltmeter won't show the low current. An alternator works just the opposite, it will deliver the current but voltage will fall off if it's failing or at it's output limit.
I had a wiring fire in my coupe. Always thought it was caused by the amp gauge. I have no idea how old the gauge was. At that time I didn't know you were not to use an amp gauge with an alternator, but I had run the car that way for years.
Most , if not all, oem application's in the 60's and 70's used ammeters with alternator's. If the gauge and wiring matches the output of the alternator, what's the problem?
Not all ammeters are made the same...the ammeter on a Dodge scares me, but those on old Chevy trucks seem to wok great for a long long time. Been running the stock ammeter in my 59 with an alternator since 1980, no issues at all.
I will agree with squirrel, the dodge ones are prone to melting, the other problem the dodges have is any resistance in the bulkhead connectors and they melt there as well. I have had more than one Chrysler product that the ammeter has come close to starting a fire, I now run a wire from the alternator directly to the battery to take the majority of the load off of the ammeter, it is no longer accurate however. Sent from my iPhone using H.A.M.B.
Might want to mention that voltmeters are basically voltmeters, either analog or digital and will read voltage anywhere you put it. Amp meters come in a variety styles. One reads amps with just a wire running behind it. Another reads amperage by running the amps into the gauge and back out. Still another runs the amps through a “ shunt” , then small wires leave the shunt and indicate amps with just a signal. It also depends where the amp meter is placed in the circuit as to what it reads. Again if everything is in good shape, good connections, and properly sized,all will work. Bones
A amp meter in a Ford back in the 40’s was an induction meter meaning no current flowed through the meter. Worked on magnetism. In fact all 6 volt Fords were like that. But an alternator puts out way more amps than the original gauge is capable of measuring. So if you have an 12 volt alternator on your hot rod putting out more than 30 amps you need a volt meter.
There was a giant fiasco in the 60's with Amp meter fires on stock Mopars. I spent a good portion of my beginning career replacing a BUNCH of them under warranty. Corrosion of connections was the cause but the problem was they were always "hot", power going to them, and caused fires even in unoccupied vehicles.
We had that problem with Police cars, in the late sixties and I believe the early seventies. With the heavy load on the electric system carryings the radios, lights sirens, burned amp gauges was common. We were lucky, no fires, but had a lot of “ no charge” problems. Bones
This is the right advice. A voltmeter will tell you everything you need to know about how your car is charging Sent from my moto g(6) play using The H.A.M.B. mobile app
An idiot light tells me all I really need to know--it's working, or it's not working. If it's not working, I get out my hand held volt meter and troubleshoot.
A bigger question what gauge wire are you running? I see a lot of 10 gauge it is good for 35 amps 8 gauge 50 and you have a 100amp + alternator. Most systems see big amps only after start up but people add killer sound systems power wires that look like battery cables hooked to the battery and expect the stock wiring from the 150 amp alternator to keep up.
An ammeter should be connected between the battery, and the rest of the electrical system. The high current from the alternator to the big accessories should never go through the ammeter. Sent from my Trimline
This is the problem that Chrysler had, it went from the Alternator through the ammeter then to the battery, with a bulkhead connector in the middle of this mess.
Where you place the amp meter will tell you two different things.If you put it between the alternator and the load it will tell you what your alternator is putting out, but not what’s going into or out of the battery. If you put it between the battery and the load it will tell you what is going into or out of the battery. Myself I like it to show what the alternator is putting out, as it moves more. Just my preference. I agree that Chrysler was a little light on their gauge. Stewart Warner made shunt equipped amp meters that could easily handle 250 amps. I also agree that a volt meter is really all you need. BUT, if you want an ampmeter, you can properly install the right one the right way with the right wire and good connections and have no problem doing it. I personally like an amp meter. Just my .02 Bones
Personally I like my amp gauge. I can tell by the draw that headlights are working, even distinguish between Hi and Low beam and directionals. I also use the kind that works off of electromagnetism, not the direct wire kind.
You are right Jim But I see countless cars with sound systems wired to the battery even from custom installs.
Most of those are on cars that don't have ammeters... and it's better for the stereo, to be connected to the battery directly.
I had this problem with an electric fan Switched to a voltmeter and it worked But my car had an ammmeter before that with no fires
Panteras were professionally built. Ammeters were the inline fuse...Poof! Car dead in its tracks, sometimes fire; sometimes lucky. Fixed a lot of those...Some were Fire jobs. (most) Yes, Chrysler Motors also.
I disconnect the battery of my '69 GTX for just that reason, the wiring is in great shape but there's no sense tempting fate. I never want to come home to the charred remains of my house and cars.
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