voltage gauge potential fire???

[nsmall]

I am going to potentially have my factory tach and speedo gauge rebuilt by "Redline gauges" here in SoCal.  They want $425.  Heard they are a great outfit, does that price sound reasonable?

I have an electric fan that runs around 19 amps (I think).  Its a Spal fan, 1610 cfm.  Its a straight blade and way to loud in my opinion.  I just bought a curved blade so I hope that fixes the noise as it sounds like a massive bee hive in my engine bay.

Anyway, Redline gauges said the volt gauge was NOT made for the fan I'm running.  HOWEVER I am running the fan off a relay to the battery so is this a NON ISSUE???

  I have a stock alternator.  As for the volt gauge, they want $240 for a rebuild to handle the new electric fan which I want to avoid. I dont have the money to have this rebuilt.  Redline gauges said I should unhook the black and red wires to the voltage gauge, and I think they said wind them together and I know they said to shrink wrap them as there is a possibility the electric fan is running to much power to the gauge on the dash and it could cause a FIRE.  Does this sound correct or like I already asked...is this a non issue?  My fan runs off a sensor I have inserted in the aluminum radiator.    I dont mind the gauge not working as I obviously don't want a fire under my dash.  Any suggestions?

Thanks!!!!!!

[cataclysm80]

E bodies originally had an ammeter (Amps) in the dash, and all the power (except starter) runs through it.
That can be problematic.  I have heard of fires.  The ammeter in my 70 Challenger was melted in two pieces when I got the car, though I didn't see any other signs of damage beyond the wire ends and gauge itself.  I spliced the wire ends together, and ran it that way for a year or two before I took the whole car apart for restoration.  (not sure if that was a good idea, but it worked)

But you're talking about a voltmeter (Volts), and that's a little different.  If you have a voltmeter, it's not stock, and we won't know anything about the capabilities of your aftermarket voltmeter because we don't know who made it, or what model it is.
I've not heard of any problems from using a voltmeter.  A lot of people have changed their factory ammeter over to a voltmeter to avoid problems.


A wiring diagram showing how your fan is wired would be helpful.  You could just sketch it out and take a picture of it or something.
You mentioned a radiator coolant sensor and a relay to the battery.

[anlauto]

Why are you running an electric fan ?

[Cuda Cody]

   I'm going to be little help here.  I run stock set ups and never have any overheating issues.  I know you live in a hot climate.  Did you install the fan because the car was overheating?  If you have a good working radiator and the fan shroud installed, you shouldn't have any over heating problems.

There's also ways to make the thermostat flow better or you can run without one too.  Not everyone likes that, but if you only drive the car on nice hot days the thermostat is going to be running full open anyway.  If you drive the car year round it's good to run the stat.  But you can get a high flow or add holes to it to make it flow more.

[303 Mopar]

First, if you can, return your new electric fan and get a stock one with a shroud.

I had Redline restore my gauges, lens, install a Volt gauge and a their stock looking tach and move the fuel gauge.  They did a great job and would be my first choice again.  And yes, that price sounds about right.  I would double check with them the lead time because they continue to become more popular and more backlogged.

[screamindriver]

To directly answer your question...There's two reasons for the factory AMMETER gauge to be a concern...
First up is the one most common problem...Old wiring combined with bad connections/connectors and the gauge stud isolating insulation that's ready to disintegrate...Once the gauge shorts to ground it's an ugly situation..Check the gauge and wiring carefully and make a decision of what needs to be done..

Second up is adding circuits to the vehicle and running it through the ammeter{as in fuse box}...If you're running a fan relay and you're feeding it directly off the battery with an isolated, fused20A lead you should be fine BUT everything is still running through the ammeter to charge ...Also remember if you're installing a high amp alternator you need to upgrade the charge wiring for the higher load which involves bypassing the bulkhead connections and amp gauge anyway...

   So in closing the safe way out is to take the amp gauge out of the equation by either bypassing or converting to the volt gauge that's why Redline is suggesting that to happen...

[cataclysm80]

I had Redline install their stock looking tach and move the fuel gauge. 

That's a neat little tach.
Does their ammeter to voltmeter conversion also have a stock look?

[nsmall]

 I have a stock set up so I guess its called ammeter.  Sorry for calling it the "voltage guage"

http://www.jegs.com/i/Derale/259/16759/10002/-1?CAWELAID=1710651302&CAGPSPN=pla&CAAGID=15769068431&CATCI=aud-179164184951:pla-210019240631&gclid=Cj0KEQiAzZHEBRD0ivi9_pDzgYMBEiQAtvxt-G0nkDoFGeTL9zbu2DSYojY-35QS_7Y3iLZIjzY1Yv4aAnB38P8HAQ

AKA...
Derale 16759
Adjustable Electric Fan Controller 150-240°F


Thats the sensor/relay I am running off the battery.  I can run it off the ignition as the fan does run a little after I turn the car off as the sensor still reads it needs to keep the fan on.  Running it off the battery was easiest so thats where I am at now.  I am unsure if it runs any power through the ammeter gauge????

My alternator is stock.

Alan, I have an aftermarket Aluminum Radiator with a aluminum fan shroud and the clutch fan will not fit now. 

I am assuming I dont have to have an active ammeter gauge?  On that note, may be best to unhook it like I originally stated and get a 3/8 wrench, take the black and red wire to the ammeter gauge, wind them together, tape and shrink wrap them as Redline suggested until I convert the gauge to a voltage set up?  I dont need a fire and if that means no working gauge...so be it unless I that wrong???

I am probably going to pass on the conversion as I dont want to spend $240

As for my Tach, I have rally gauges, the tach runs way higher than it should and I heard the speedo is notorious for breaking and making noises once broken so I will probably spend the $425 to have those two rebuilt when the dash is out.  Does that sound like a good idea?

As always...THANKS

[cataclysm80]

Thats the sensor/relay I am running off the battery.  I can run it off the ignition as the fan does run a little after I turn the car off as the sensor still reads it needs to keep the fan on.  Running it off the battery was easiest so thats where I am at now.  I am unsure if it runs any power through the ammeter gauge????

Feel free to listen to what others have to say, but here's my opinion, based on the info you've provided.

Your yellow relay wire is hooked to battery (power all the time) instead of to a switched ignition source.   The result is that your fan will continue to run after you've shut off the ignition, until the radiator temp gets low enough to shut the fan off.
The downside is that running the fan with the car off drains the battery.  It's probably not enough of a drain to leave you with a dead battery.  If it were, you'd probably already have been stranded somewhere with a dead battery.  When you start the car, the alternator will have to kick on to charge whatever amount of power has been drained.
The engine temp will normally increase after you shut off the ignition because the water pump is not circulating coolant.  Having the fan continue to run after you shut the ignition off does not help to cool the engine, it only cools the radiator, and that coolant is not going into the engine unless the engine is running.
With the yellow relay wire hooked to the battery, it isn't getting power through the ammeter, so that's sort of ok, see more notes further down...
Having the yellow relay wire hooked to a switched ignition source would be getting power through the ammeter, which is what you're trying to avoid.
Other than wasting a little battery power after you shut the ignition off, having the yellow wire hooked to battery seems ok as long as you don't end up with a dead battery.   I'm not sure what temperature you have the fan set to turn on at, but if it's the lowest setting of 150 degrees, and the turn off temperature is 10 degrees less at 140 degrees, AND you live in a very hot climate, then there is some potential for a metal car parked in the sun on a hot summer day to reach 140 degrees and operate the fan non-stop until the battery is dead.  Since the turn on temp is adjustable, setting it to a higher temp setting would decrease the chances of that happening.


OK, so as is, your fan is drawing power straight from the battery, not through the ammeter.   Here's the problem.  All the power that your fan is taking from the battery has to be put back into the battery by the alternator, and the alternator is sending that power through the ammeter.  If that's more power than the ammeter can handle, you'll fry the ammeter. 
I'm not sure how much power the stock ammeter can handle before it's toast, but if Redline Gauges says you're putting to much through it, then they're probably right.  It sounds like your current setup is risky and should be changed.
The simple solution is to not run the alternator charge wire through the ammeter.
It's not unusual to have ammeter wire problems at the bulkhead disconnect anyway, so this will also prevent problems in that area.
Instead of running the alternator charge wire through the firewall, just run it to the battery stud on the starter relay.
(If you run a new wire from the alternator to the starter relay, remember to disconnect the alternator wire going through the firewall.)
Make sure the wire is the right gauge for the amps of your alternator output, and that you have a fusible link on the wire by the starter relay.  (see chart below)

Having the alternator bypass the ammeter should mean that the ammeter is no longer functioning as intended. 
I think it would read on the Discharge side all the time.
I think that normal power would still go through it for all of your interior electric stuff.
As screamindriver mentioned, the paper gauge stud isolators are probably ancient and ready to disintegrate, which is hazardous.
Since you're going to have the instrument cluster out for speedometer and tachometer work, you can inspect and replace the paper stud isolators, or just connect your two ammeter wires together to bypass the gauge.  If I remember correctly, the two ammeter wires each have an eye, so you could probably hook them together with a small bolt and nut, and then electrical tape over it like crazy to keep them from shorting against anything in the dash.

[Cuda Cody]

 

[nsmall]

cataclysm80, dang, that was an awesome response.  I know very little about wiring, but you just took care of business.

I have a few questions for you.  please feel free to provide a quick response, I hate wasting peoples time.

Any idea of what size of gauge wire I should run?  My Alternator: ripple...18 amps, output @ 6000 RPM 58 AMPS, Output at 2000 rpm 41 AMPS.  Part Number 213-2012

    I am assuming an auto parts store like Napa or Orielly's sells the wire with the a fuse set up in the wire or is this something I have to special order?

Lastly, assuming I can make this switch, as long as my grounds and wires and connections look clean, leaving the ammeter stock should "most likely" be okay?  Otherwise I can unplug it like Redline said and wind up the black and red ammeter gauge wires.  Redline suggested this originally because I think they thought the new electric fan I installed was hooked to the ignition.

Thanks for your help.      You are good at explaining information as I often get confused easily.  Plus you just saved me some 

Neil

[Cuda Cody]

@cataclysm80  is a wealth of knowledge and he's super happy to share it!  People like him make this hobby so much more enjoyable.   

[cataclysm80]

Again, this is based on the info you've provided, and also it's been a few years since I've regularly worked on cars, but here's my thoughts...

You had mentioned that your alternator was stock.  The stock wire used by the factory was 12 gauge.  If your alternator is really stock, and 12 gauge was sufficient then, it should still be sufficient now.


Then again...
The highest alternator output you listed was 58 Amps @ 6000 RPM. 
That falls around the range of 10 gauge wire on the chart I posted.
Smaller gauge wire (bigger numbers) would be bad because it's unable to carry the current load.  (It would get hot, melt the insulation off, and short out.)
Bigger gauge wire (smaller numbers) won't hurt anything.
Wire resistance increases with length.  The chart I posted is from an old Richard Ehrenberg article. 
( http://www.allpar.com/history/mopar/electrical.html )  He really knows his stuff, but there's no mention of wire length.  It's probably correct if your battery is in the stock location.  If you've relocated your battery or starter relay further away (trunk?) you'll probably need bigger wires.


Then again...
Here's the chart that Powermaster (alternator manufacturer) uses as a guide for alternator wire sizing.
According to this, 10 gauge wire is ok if it's not longer than 4 feet.  4 feet sounds like it wouldn't be long enough to route the new wire back along the firewall along with the existing wires.  This chart suggests 8 gauge wire up to 10 feet long.

[cataclysm80]

Then Again...
There is this chart

It seems that which wire is the correct size just depends on who you ask.    

[cataclysm80]

I'm sure that there must be a correct answer somewhere.  It's probably found in an electrician's technical journal somewhere.
What you're looking for is a wire capable of carrying about 60 amps of current safely.
Perhaps it would be best to check with the manufacturer of the brand of wire that you intend to use.

https://www.tessco.com/yts/industry/products/itm/automotive/get_wired.html
https://www.wirebarn.com/Wire-Calculator-_ep_41.html
http://www.rowand.net/Shop/Tech/WireCapacityChart.htm