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FE Power Forums => Non-FE Discussion Forum => Topic started by: Dubs1 on February 20, 2021, 01:22:51 PM

Title: Ammeter guage install
Post by: Dubs1 on February 20, 2021, 01:22:51 PM
Hi Guys


I have a question  for all the sparkies out there.  I about to install an ammeter guage on my 68 GT fastback with a tach dash cluster, ergo no ammeter guage. 
At what  two points  underdash/engine compt  do I run the two connecting wires?  Off the selonoid switch? If ignition switch, which

 post.

Other locations?

Pls advise

All the best

Dubs in Denver
Title: Re: Ammeter guage install
Post by: frnkeore on February 20, 2021, 01:39:32 PM
If your not dead set, on a ammeter, I would install a voltmeter.

You get much better feed back from a voltmeter and they are much easier to install. You only need a good ground and a good + source, such as the feed to the ign.

Then it will tell you how well the generator is working, by monitoring only the voltage.
Title: Re: Ammeter guage install
Post by: Tommy-T on February 20, 2021, 02:48:24 PM
If your alternator puts out more than 40 amps or so, an ammeter is a really good way to catch your car on fire.

Say no to ammeters.

A voltmeter tells you a lot more about your charging system. If it says 13.5 or more at any given time, you're good to go.
Title: Re: Ammeter guage install
Post by: 475fetoploader on February 20, 2021, 03:01:06 PM
My first hot rod had a 454, and a 100 amp alternator from the motorhome that donated the block. I let the smoke right out of some Autometer stuff. I was in the teenage stage where my dad let me discover the world on my own. I’m pretty confident I was s great source of humor for him. Ditto on volt meter.
Title: Re: Ammeter guage install
Post by: shady on February 20, 2021, 05:02:25 PM
The down side to an amp meter is that the whole electrical system of the vehicle has to pass thru it, hence the need for heavy cabling inside the cabin. The up side of it is that you can see any draw on the system. I'd go with a voltmeter, much easier and safer.
Title: Re: Ammeter guage install
Post by: cjshaker on February 21, 2021, 12:19:22 AM
+5
A voltmeter is a much better choice.

If you don't want an aftermarket gauge hanging down from your dash, you can take a simple voltmeter, wire it directly to a powerport plug (or cigarette lighter plug in the case of our old cars) and simply plug it into the lighter outlet when your driving. It'll give you a direct voltage reading, and you can unplug it and stuff it in the console or glove box when you park the car. Old gauges are pretty easy and cheap to find.
Title: Re: Ammeter guage install
Post by: turbohunter on February 21, 2021, 07:32:42 AM
If you are thinking/concerned about the clean aspect of a volt meter install, there are companies that make volt meters that look like the original ammeter.
Rocketmans Classic Cougar for one. They do volt meters for different vehicles. I used one in my truck.
http://www.rccinnovations.com/index.php?show=menu-volt-all
Title: Re: Ammeter guage install
Post by: cattleFEeder on February 21, 2021, 08:14:55 AM
+1 on rocketman gauges.
Title: Re: Ammeter guage install
Post by: BattlestarGalactic on February 21, 2021, 09:33:31 AM
Ditto.

In the sixties you only have maybe a radio and a pair of old sealed beam headlights.  Not much current draw.   Today, not so much.  It would take a battery cable run into the car to operate an AMP meter correctly.  Thus the fire hazard.

Little electric theory:

A Volt meter is placed in Parallel to the power supply.  Like measuring a battery.  It reads the potential power available.

An Amp meter is placed in series with a LOAD.  It reads the current running through the circuit.  If you put an Amp meter across a battery....Boom.....the meter releases the magic smoke.

(https://electricalacademia.com/wp-content/uploads/2017/07/Ammeter-Vs-Voltmeter-1.gif)
Title: Re: Ammeter guage install
Post by: Falcon67 on February 22, 2021, 01:03:28 PM
As above - use a volt meter.  You'll get proper feedback on charging system status.  Ammeter = fire hazard, even in the old days.  Now with dirt cheap 100+amp alternators, no way. 
Title: Re: Ammeter guage install
Post by: C8OZ on February 22, 2021, 01:17:58 PM
Not to drag it off topic, but did/does anyone market an automotive ammeter with the shunt at the battery and only a low-amp signal to the gauge? I haven't installed one in a car in decades, but that's the only way I'd be comfortable nowadays.
Title: Re: Ammeter guage install
Post by: cjshaker on February 22, 2021, 03:02:10 PM
If you are thinking/concerned about the clean aspect of a volt meter install, there are companies that make volt meters that look like the original ammeter.
Rocketmans Classic Cougar for one. They do volt meters for different vehicles. I used one in my truck.
http://www.rccinnovations.com/index.php?show=menu-volt-all

That's a neat upgrade. Thanks for that link, Marc. I was never comfortable leaving the battery cables connected on my Mach, just for that reason of the ammeter. That helps eliminate a fire potential on these old cars.
Title: Re: Ammeter guage install
Post by: RustyCrankshaft on February 22, 2021, 05:44:22 PM
Not sure you'll find any in the Summit catalogue, but you can find shunt or inductive amp gauges that do not need to be in series. It's not uncommon for a lot of the equipment we run at work to have them. Murphy Gauge, Stewart Warner industrial, Simpson, etc. all make them if you really want to see how much load is on the alternator/generator.
Title: Re: Ammeter guage install
Post by: BattlestarGalactic on February 23, 2021, 04:29:03 PM
Not to drag it off topic, but did/does anyone market an automotive ammeter with the shunt at the battery and only a low-amp signal to the gauge? I haven't installed one in a car in decades, but that's the only way I'd be comfortable nowadays.

Interesting.  You would think with all the new technology, that someone would come up with a system that just uses an inductive coil at the battery cable and some kind of device to send a signal meter. 

I have a similar kind of thing on my Onan generator.  It is a gauge system with power/amp/watts and uses a small coil on the output power lead.
Title: Re: Ammeter guage install
Post by: Dubs1 on February 23, 2021, 08:10:27 PM
WOW!!!!!!

What a helluva response    You guys  are great!!


MUCHAS GRACIAS  VOLTMETER IT IS.
Title: Re: Ammeter guage install
Post by: cjshaker on February 23, 2021, 08:18:32 PM
Not to drag it off topic, but did/does anyone market an automotive ammeter with the shunt at the battery and only a low-amp signal to the gauge? I haven't installed one in a car in decades, but that's the only way I'd be comfortable nowadays.

Interesting.  You would think with all the new technology, that someone would come up with a system that just uses an inductive coil at the battery cable and some kind of device to send a signal meter. 

I have a similar kind of thing on my Onan generator.  It is a gauge system with power/amp/watts and uses a small coil on the output power lead.

That is what is used on all the chillers that we run on campus, to monitor current draw on various stages of the big compressors and electric motors that drive them. I wouldn't think it'd be hard to adapt to an automotive system; you'd just have to come up with the right inductive coil and meter. Unfortunately, I'm not up on that stuff enough to know what's out there that could work on a low voltage DC system. I should ask the lead tech guy at work. He's a pretty smart fella and would know.