Alternator wire, where does it run to?

Try this.

John

@jjones posted:

A previous owner installed a new alum rad & 3 fans which are putting a drain on my electrical system.  On hot days my battery will slowly drain instead of charge, leaving me stranded whereever I decide to shut the engine off.

Hence I would like to upgrade the alternator from 75A to 100A.  I also noticed a butt splice in the alternator wire so I thought I should inspect or replace it.  I assumed it would go straight to the battery or to the "batt" side of the starter solenoid.  It doesn't.  I recently replace the ammeter in the dash with a voltmeter and saw the size of those leads!  Perhaps one of those runs back to the alternator and other to the battery?  Any links to a schematic would be helpful.  Thanks

When you removed the ammeter did you connect the two heavy wires together?

Did you connect the voltmeter to a switched power source?

Do NOT connect it to the heavy ammeter wires.  Doing so will drain the battery, even with the ignition key turned off.

John

Thanks everyone.  I did connect the heavy Black & Red wires to bypass the ameter that I removed.  For now its a #10 bolt with double shrink wraps.  The voltmeter takes a acc wire for input.

Between the battery charghing system schematic and an older thread, volt gauge qustion, it made sense.  Although my brain was saying don't connect red to black, that is exactly what to do.

The schematic shows them running to + on the battery, although the symbol they use looks like a ground at first glance.

The voltmeter is working great now.

On the new fuel gauge I added a 10 ohm resitor to mimic the fuel level when I made the swap.  It's only one data point so I may increase the resistance later.  For now the gauge is working.

Temp gauge appears to work so I'll leave that alone for now.

The oil pressure gauge reads 0, so I will swap the oil pressure sender (240-33 ohm?) with a vdo sender (10-180 ohm) to see if that fixes that.

The fact that I can see the gauges at night is so nice.  BTW these gauges seem to be in limited supply.  Black face, chrome bezels, slip right into the stock holes.  The "spin-lok" mounting hardware is ok for the two middle gauges, but interferes top & bottom when trying to put the cluster back in the dash.  I had to take the retaining rings off the back of the voltmeter and oil pressure gauges and rely on a friction fit for now.  Thinking on a better solution without having to hack up the dash for more clearance.

VDO - Vision Chrome Series (being phased out?)

p/n 332-193 Voltmeter 8-16v

p/n 301-195 Fuel (240 - 33 ohm)

p/n 310-195 water Temp 100-250F

p/n 350-194 Oil Pressure 80 pis (10-180 ohm)

As a recommendation, I would wire your fans directly from the battery to separate relays.   You can also put a direct wire from the battery to the hot side of the relay trigger terminals allowing you to simply run a ground side wire back into the cabin through a toggle switch if you want to control your fans manually.  This eliminates all the fan amps running through the rest of the car's system.

Yes, I used a relay. The fans pull directly from the battery. That’s why the ammeter never went negative, showing me that the battery was slowly draining.

If the fans are powered from the battery an ammeter will show a positive charge when fans are running. On my car with everything running it pulls over 85 amps so you may be right in needing to go to a larger alternator.

I’m glad you said that. I could tell when the fans came on because the ameter would max out at 75A. A little alarming.

I have a 75 amp alternator along with big Spal fans and Pantera Electronics fan controller.  The fans pull a lot from the system and I am somewhat on the edge of running low on voltage but always seem to make it home with a little extra.  I have been using this simple volt meter to help me know how good or bad things are.  13.9 volts while driving is great and anything less than what you see below (12.7) is probably not good.  This volt meter just plugs into the cigar lighter.  My battery rests at 12.9 to 12.7 as you see here.

Also, you had originally asked where the alternator wire runs.  On this 72 car it starts at the alternator as a black wire and goes up to the ammeter.  Then it goes to the fuse block.  In the photo, label 1 is the black wire at the alternator, 2 is the black wire mated with the red wire where the ammeter normally is (the wires are taped together in the photo), and 3 is where the red wire joins the fuse block.

...3 Recommendations:

1. Replace Alternator with 100 amp alternator, with INTERNAL Voltage regulator, and INTERNAL Cooling FAN. 'Hall Pantera' use to have these. The Internal Regulator Totally Eliminates the 'External Regulator'! I Big Leap for Panterakind!!

2. Install a Battery Disconnect switch of ground wire in front Bonnet.

3. Use a 12 Volt Battery TENDER, at ALL times when the Pantera is Not Running. Especially when Sitting Over Night! This was My Biggest Help, in Our HOT Valley, and My Garage! Really Keeps the Battery ALIVE!

ALL of Your Problems will Disappear...and Every Morning and Stop, Your Cleveland will Fire Right UP First Time, Everytime!!

You have My Personal Guarantee!

MJ

...P.S. The 'Voltmeter' was Your Best Idea! I'am sure you have noticed, after a Start, Your Charging 14+ Volts, slowly creeps down to 13.6 Volts, Running, Shown on My LED Digital Gauge. 12.2 Volts Not Running, ALL Electricals ON.