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Discussion Starter #1
I was wondering about using the horn relay as the second connection point behind the the alternator for the measurement through the gauge on my 67 camaro. Like the diagram in the link. Thoughts or experience anyone would like to share?

 

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Link no worky.
 

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david on my 68 i went from junction block behind battery, with the black wire from gauge,with a fuseable link the black with white stripe wire from gauge hooked to the large red wire on the horn relay lug, with fuseable link works great ralph
 

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Discussion Starter #5
Thanks for the info Ralph - the thing I haven't done is fuseable links. Sounds like that may be something I need to pursue for circuit protection?
 

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david you need the fusebile links for circuit protection,16 gauge wire with the fusebile links at battery an horn relay an it should work ralph
 

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Illustration shown will work fine as long as the existing wire going across the rad support is disconnected at both ends.

Make sure ammeter will show current shown, a 60-0-60 gauge will be fine.
Use 8 AWG multi-strand wire because of the length shown. I take it this gauge will be in the interior and not mounted on the rad support?

If you are using the ammeter to only show battery discharge/charge, you could bypass all the OE wiring and attach one lead to the BAT terminal on the alt to meter, the other side of the meter to solenoid post. This would also eliminate the positive pigtail from the battery clamp. Still use 8 AWG multi-strand wire. Be sure to disconnect pigtail at junction block or horn relay buss bar.

You will have to reverse the ammeter connections shown as current flow will be in the opposite direction to charge the battery.
 

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I would think long and hard about the wisdon of installing a series ammeter in the first place.

ALL stock ammeters in chevies were external shunt style, they did not install in series with the battery.

Running the car's primary charge wire that far is worrysome to me, just an opportunity for bad things to happens. Have you ever direct shorted a car battery?
Watching those 600 plus cold cranking amps arc to ground is awe inspiring, not something I'd ever want to see or hear, particularly if it was happening to 15 feet of 8 gauge wire where it passes through the firewall.

Get a voltmeter. It tells you more anyway.
 

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Yes, but aftermarket ammeters are not. The wiring precautions all depends upon the engineered safety placed into the installation.

If he is using an OE ammeter, then yes, the OE gauge is measuring millivolts of voltage drop on a length of wire, a parallel millivoltmeter.

Gauge selection is personal preference. Voltmeters are nice, but a series ammeter on the battery tells me the condition of the battery. A voltmeter measuring the electrical system pressure, won't tell me the internal condition of the battery whether it has a dead cell, shorted cell, or slowly aging as shown by the current being measured.
 

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Yes, but aftermarket ammeters are not.
That's unfortunate. I was not aware of that.

Personally I'm with Jim on volt meters are better though I know this could turn into a "cast-iron or aluminum head power" thread :D

My only problem with ammeters are that they read zero when all is well. That really doesn't tell you much about the health of your battery. Batteries usually develop high internal resistance when they fail or begin to fail. Ultimately that results in lower charging currents and gives the impression that the battery is fully charged. Volt meters on the other hand let you know what your cranking voltage is as well as the system running voltage.

Hopefully I don't start a war here, but feel that volt meters do in fact give you a better indication of system health, and internal shunt meters are inherantly more dangerous. The caveat seems to be that no one makes a replacement volt meter for the OEM ammeter.
 

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Yes, but aftermarket ammeters are not.
That's unfortunate. I was not aware of that.

Personally I'm with Jim on volt meters are better, though I know this could turn into a "cast-iron or aluminum head power" thread :D

My only problem with ammeters are that they read zero when all is well. That really doesn't tell you much about the health of your battery. Batteries usually develop high internal resistance when they fail or begin to fail. Ultimately that results in lower charging currents and gives the impression that the battery is fully charged. Volt meters on the other hand let you know what your cranking voltage is as well as the system running voltage.

Hopefully I don't start a war here, but feel that volt meters do in fact give you a better indication of system health, and internal shunt ammeters are inherantly more dangerous. The caveat seems to be that no one makes a replacement volt meter for the OEM ammeter.
 

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That's unfortunate. I was not aware of that.
At least on the outside of the gauge. One still has to install the gauge as a real ammeter. Internally, the high end gauges are a shunt meter, meaning the shunt is inside verses outside as with the OE design.
Personally I'm with Jim on volt meters are better, though I know this could turn into a "cast-iron or aluminum head power" thread :D
I agree. A voltmeter is nice and yes it indicates the system voltage of the mode in operation at the time of measurement and is safer to install. Personal preference.

If it be known, all the farm tractors we owned, AC WD, WD45, IHC M & MTA, Oliver 77 & 88, JD B & D, MH 44, & Ford 8N, had ammeters. First thing we would do to all of them is pull out the 6-volt battery and drop in an 8-volt and crank up the reg alittle to 9.5 volts. Never had a problem. When the ammeter started showing a charge all afternoon when in the field, suspect the battery after tightening the belt.
You are the environment you grew up in.

Let me get you people of this thread the next round.
 

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I would think long and hard about the wisdon of installing a series ammeter in the first place.

ALL stock ammeters in chevies were external shunt style, they did not install in series with the battery.

Running the car's primary charge wire that far is worrysome to me, just an opportunity for bad things to happens. Have you ever direct shorted a car battery?
Watching those 600 plus cold cranking amps arc to ground is awe inspiring, not something I'd ever want to see or hear, particularly if it was happening to 15 feet of 8 gauge wire where it passes through the firewall.

Get a voltmeter. It tells you more anyway.
Yeah! what he said!:hurray: I ran one of these old school ammeters back in the day. I never had trouble BUT the possibility exists to loose all power to the car with this set up. Someone else I know bought a Camaro with a fuel pressure gauge in the dash and the line ran thru the non-grommeted hole in the fire wall with all the gauge wires, Up In Smoke wasn't a movie for that guy!

Jeff
 

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Discussion Starter #14
Thanks all for the feedback. It is appreciated in decision making. However, while I had the time off but before the comments came in, I wired the ammeter up in series, sorry to say without fusible links, and tried to test out my gauges. I turned the key to the ON position and then turned on the headlights to see if the illumination lighting was working in the gauges, and the car went dead. After a couple hours messing around, found that the horn relay was lunched. (pretty sure it was 41 years old anyway). I ordered a new one and installed it. Disconnected the in series ammeter wires and now am back to where I started EXCEPT that I have no ammeter (no biggie – maybe a volt meter now :) ) and now no headlights. Fuses are good. From searching the forum, it looks like it could be the dimmer switch or the head light switch itself. I guess I’m off to the parts store again.
 

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If the car is dead, you might look at the fusible link on one of the two red wires connecting to the horn relay buss bar. It may be open or a bad crimp on one of the terminals.

Wire brush the terminals on the red wires.
 
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