When did they stop using AMPS and switch to VOLTS

First of all I know nothing about car wiring, the shit scares me. A friend told me there are no Ampmeters used today only Voltmeters. Could someone explain this to me?

 

my understanding is the made the switch around the same time as from generators to alternators. I couldn't tell you why or if this is correct. Just what I heard.....and I'm curious to know too.

 

In the six volt generator days, 30 was a big number. A ten gauge wire carried the six volts and the amps through the gauge. Later, when we got to 65 amps, the current was to great to safely go through the gauge. A small wire will tell you how many volts you have. To make the amp meter work, all the current for the whole vehicle needs to go through the gauge. A volt meter is safer, and less fire prone.

 

I measure amps at work all the time. Alt's develop ac that is changed to dc, I hope I don't have that backwards, but I'm sure I'll be corrected quickly if I do.
Generators develop direct current right off the bat.

When I check the alt I check amps, diodes, regulators, I'm tired trying to think.

 

It's not really an answer to your question, but I do know historically that in some vehicles, ALL the charging current went through the amp gauge. If the amp gauge quit then you had NO charging system. Personally, I say the volt gauge is better. When you drive a vehicle with an Amp gauge, it tends to show a charge when the vehicle is first ran (few minutes), then the gauge sits in the middle like it's not charging. A volt gauge should show 13.5-14.5 volts whenever the vehicle is running. If the charging system fails on a volt gauge system, you will see it right away due to the gauge dropping to 12ish volts.

 

Dont know when they switched over to volt guages but in my opinion its safer. With an amp guage current has to flow from the alternator through the firewall, through the guage itself, back through the firewall then into the battery with a couple of connectors in between, thats alot of places for bad connections and potential problems or worse a fire.

 

IIRC voltage gauges are thought to be safer to use on the high output charging systems of modern cars. An amp meter needs to be hooked up in series with all the circuits in the car, so all the amperage for all electrical on the car runs through one wire under the dash to and from the amp gauge. A volt gauge is hooked up in parallel, so there is a lot less power running through it, and a lot less chance for a short on the circuit to start a fire. Just my $0.02

Edit: damn I type slow

 

So you want to know when the cluster changed from an ammeter to a voltmeter? I'm curious too, but I'm sure each car company was different.
Any one know this?

 

There are a lot of reasons to switch from Amp meter to a voltage meter. The manufacturers probably did it as a cost saving measure. The main problem with an amp meter is that you have to run a big wire into the car behind the dash and if it shorts out you have a big problem. The original generators only put out 30 amp or so thus the wiring wasn't too big (10 gage). But as the output of the generators became greater the wire had to get bigger as well. When alternators were introduced then the problem became acute. It is nothing to have an alternator rated at 100+ amps which means the wiring to the amp meter would be the size of welding cable. This big wiring would be unwieldy and very expensive to install. By switching to a volt meter the wire stays the same size (usually 16 or 14 gage) regardless of the amperage. There is a "work around" if you want an amp meter and you have a large alternator. You install a "shunt" which is nothing more than a "electrical by-pass" for the amp meter. With a shunt installed the amp meter only reads a portion of the amps actually being produced. Older private aircraft often have shunts installed so it is a "known fix" to using an amp meter with a large alternator or large generator.

 

Thanks for the replies, but what I was asking is was the "Stuff" for lack of a proper electrical term that flows inside the wires AMPS or VOLTS? I know it can kill you or burn the car up, just wondering why the "Stuff" was changed.

 

If I am understanding you want to know the difference between amps and volts?

Check this out...


http://hyperphysics.phy-astr.gsu.edu/hbase/electric/watcir.html

http://www.windows2universe.org/phy.../electricity/circuit_analogy_water_pipes.html

 

The "Stuff" inside the wires never changed, just how it was used to tell you what was happening through the use of a gauge

Voltage is the amount of electrical pressure. Amperage is the volume of electricity that flows past a particular point in a given period of time.

Think of electricity like water in a hose. The water is pushing to get out of the hose through the nozzle. This is pressure is just like electrical voltage.

When you open the nozzle, the water flows out of the hose at a particular rate (lets say 9 gallons per minute). This is the equivalent of Amperage.

It is true that it's the amperage that kills you. The amount of electricity that flows through you is the dangerous part, not how hard it is being pushed.

 

Had a 65 Dodge Dart w/amp gauge and a melted cluster.

The car would intermittently quit running, then one day the dash was smokin'. At least after the repair it was a reliable car again. (installed a volt gauge)

 

The "stuff" that flows is electrons. More electrons = more amps. Voltage is the force pushing (or pulling) the electrons.

Electrons have a negative charge. They are attracted by a positive charge.

Nothing was changed except to measure the voltage instead of the current flow (Amps).

Well, anyway, hotroddon types a lot more & faster than I do........

 

Were you or are you a teacher, cause that's a very good answer.

 

I know the volt gage shows volts if it is charging but does it show you anything else?
My amp gage tells me if the battery was unusually low when I start the engine, It tells me when the battery has charged up, it flickers when I put on the brakes and that tells that my brake lights are working and of course it tells me when the alternator is not charging.
Can the volt gage talk to you like that?

 

So an AMPMETER is a piece of shit and should never be used but if I connect a VOLTMETER to the two wires everything is golden?

 

If you are going to run a low amp generator in a nice simple 6 volt hot rod, then you are golden with an amp meter.

 

No kid, that aint rite. I have been using amp gauges for 40 years on many of my old cars and will continue but I will be using the Delco SI one wire so I will have no worries about burning anything up

 

No. Don't put a voltmeter in where the ammeter goes. It will probably smoke. A voltmeter goes between ground and any hot wire. An ammeter goes in the charging circuit. I use both to get a more complete picture of the operation of the charging circuit. They each tell only part of the story.

 

The ideal Hot Rod IMO wouldn't have any extra wire, an Amp meter and maybe a dash lamp to view the gauges at night, if I desided to wire head lights on it.

 

Outstand reply

 

here's another thread on the same subject:

http://www.jalopyjournal.com/forum/showthread.php?t=244327

 

If I was to have only one gauge it would be an ammeter. It provides the most information. You can have an alternator or generator making good voltage but providing little or almost no current.

 

Exactly why I measure amps at work. Tells me a lot more of whats going on.

 

You do NOT have to run all the current for the whole vehicle though the gauge to get an accurate idea of whats happening to your charging system. I dont do that on my cars.

Is a volt meter safer and less prone to a fire if it shorts out? I dont think so.

 

ok ..so amps is to do with the size of the current, voltage is to do with the speed...but whats a Watt?

 

Chevy had what is called a shunt type amp gauge on the early to mid 60s trucks. It's all small gauge wire, so the full charging circuit does not pass through the gauge.

 

volt meter is safer, it reads voltage using very little amperage. that's not to say that using an amp gauge is unsafe, just a higher risk.

 

Everyone go read what Bruce Lancaster has to say on this thread http://www.jalopyjournal.com/forum/showthread.php?t=244327