Amp Guage Questions

[vping]

I have an aftermarket amp gauage that came with my '67 but was not hooked up.

What are the benfits to having an amp guage?

If I were to hook it back up, are they positive or nagative ground? The car has been converted to negative ground but I am not sure how long it has been with the car so I do not want to hook it up incorrectly. Actually I am not even sure if it is possible to hook it up incorrectly.

 

[1965_MGB]

Some find amp gauges helpful, but I personally prefer a voltmeter. Amp gauges are wired directly through the charging system, and can cause some problems if they go bad (like a fire).

I'm not sure if there is an issue with positive or negative ground, but I would do some research before hooking that one up to your charging system.

Also, make sure the gauge is not going to be overloaded with amperage by your charging system, such as if you have changed to an alternator with a higher charging rate than the gauge shows.

 

[vping]

Another question I just tought of is that I am running a Generator and not an alternator. Should you run on or the other?

 

[jlaird]

It makes no difference at all. Gen or alt. nore does it make any difference on pos or neg. If you get it wrong just reverse it.

 

[David_DuBois]

If you decide to use the ammeter, make sure that the wires going to it are heavy enough to handle the charging current from your generator and that the wires are routed such that they are not in danger of being chaffed by anything. If the insulation gets rubbed through, you are in for a spectacular display of sparks and smoke.
Cheers,

 

[Steve_S]

Amp meters get a bad rap because some people with old wiring have suffered under-dash fires. If the gauge and wiring are in good order it should be fine. A countless number of cars have used them with no problem. I enjoy the one in our TC and wish my other cars had them installed.

You can connect the gauge either way. If it reads backwards, just flip the two wires around.

 

[Stewart]

From my avation experince I prefer the volt gauge over the amp guage as I find it easier to read. Once the battery in recharge from starting the needle is going to be just on the plus side of the center mark depending on load and when your bouncing around your going to have a tough time reading it. With the larger scale of the volt meter its very easy to read and you can quickly pick up any problems with its larger movement. In the end however both do the same job well.

 

[Dave Russell]

If I were to hook it back up, are they positive or nagative ground?

Just a note:
The meter does not connect between anything & ground. If it was, there's sure to be fire. The ammeter usually goes in line with the generator output to battery wire. Or sometimes in line with the main battery to "rest of the car" wire.

I'm sure that's what you meant anyway.
D

 

[PAUL161]

Read the little article I posted on Volt Gage verses Amp Gage. Amp meters have been around since the first automobile had a charging system installed. Amp meters are an in line instrument and I've never heard of an automobile being destroyed because one of them went bad. Bad wiring yes, but not a bad gage. their not grounded! Volt meters have been around forever, but in automobiles, they are a "new generation" idea, along with idiot lights. Not that their bad, but should be paired up with other instruments.

 

[Ed Kaler]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]If you decide to use the ammeter, make sure that the wires going to it are heavy enough to handle the charging current from your generator [/QUOTE]

Not necessarly so, Dave /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif!!

It DEPENDS on whether the Ammeter is of the "shunted" type or "NON-shunted" type/bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

"Shunted" can be used with either 14 awg or 16 awg wire BUT, NON shunted REQUIRE wire size to be at least one size HEAVIER guage wire than the genny/alt is capable of outputting!!

/bcforum/images/%%GRAEMLIN_URL%%/cheers.gif

Ed

 

[DrEntropy]

NON shunted REQUIRE wire size to be at least one size HEAVIER guage wire than the genny/alt is capable of outputting!!

And THAT's why a voltmeter is in my cars in lieu of an amp gauge. If the voltage indicator does something 'funny' I can always use a REAL ammeter to test output. Plumbing up a gauge for amps is a bit overkill for most LBC's, IMO.

 

[David_DuBois]

Ed - If you are talking a remote shunt, I'll agree - in that case you essentially have a voltmeter inside the car, calibrated in amps and the shunt is mounted somewhere near the generator (a much better set up IMO, than a non shunted meter inside the car with heavy current carrying wires routed to it).
Cheers,

 

[Ed Kaler]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] If you are talking a remote shunt, I'll agree - [/QUOTE]

Yep, Dave. /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

At one time in my glorious past, I designed Small Rescue Trucks and Ambulances AND said electrical systems /bcforum/images/%%GRAEMLIN_URL%%/grin.gif !!

And the use of "shunted" vs "remote shunt" styles was actually dependent on chassis choice and/or elec. gear spec'ed..

Firemen and amb. Co. Owners/Operators ALWAYS KNEW that all they designed and/or spec'ed was PERFECT /bcforum/images/%%GRAEMLIN_URL%%/hammer.gif,
which was more often then not entirely WRONG!! /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif

Me

 

[Sarastro]

I like having an ammeter. It indicates directly whether the battery is charging, or how much it's draining. That's really what you want to know. The voltage can vary a lot throughout the electrical system, depending on where you measure it. It's hard to determine whether the battery is charging simply from the voltage.

I have both an ammeter and voltmeter. As far as the shunt issue is concerned (and, any high-current ammeter has a shunt somewhere), I circumvented it neatly. Here's how.