67 Barracuda Heavy Electric Load

-
D

DallasMan2000

Well-Known Member
Joined
Aug 20, 2023
Messages
56
Reaction score
15
Location
Dallas
So my 67 barracuda has an electric radiator fan and I have noticed that the car wants to die after about an hour of driving then coming to a stop light when driving at night. Wondering if the extra electrical load is too much for extensive driving. There is a high output Mopar alternator on the car now. It seems like even a standard alternator should keep up. Last night I drove for about an hour with lights and wipers on and electrical radiator fan running. Usually I have a trickle charger on the battery before driving but did not this time. When I got back home the car would die when I stopped it at an idle. Usually it starts right back up but this time it would not even turn over. I charged it up for about an hour and it started right up again so I could get it back into the garage.

Do I need a voltage regulator that allows more amperage to pass through during normal operation?
 
Are you running all this through a stock wiring system???
 
wires are sized by load. Stock wires were sized by Chrysler to handle the load that they were built with. There are ways to isolate additional loads from things like electric fans, but they can't just be patched in to the original circuits without bad results.

Is there an amp gauge in the car? does it show discharge at low rpms? Is there a voltmeter in the car and what does it say when fully charged on your trickle charger, and does the voltage get lower as you drive the car? what is the idle speed in gear when the carb is off high idle? post a picture of your current voltage regulator.
 
What's the alternator output?
 
With the engine idling, & all of the accessories turned on, check the voltage at the battery. Should be 13 or higher. A fully charged battery is about 12.6-7v. If you read lower than this, then the battery is discharging.....
 
All good advice. You should definitely add relays for your lights, electric fans and other added high current drawing items. All your power goes through a most likely undersized stock wire that goes thru your amp meter, light switch to fuse box. This may not be your problem right now but it could very well be in the future. Lots of posts on headlight relays and more out there along with other wiring upgrades especially if your using a higher amp alternator. JMO
 
This sounds like the alternator is not able to put out enough current for the fans, headlights, and everything else on the car. If the voltage regulator is working correctly, changing it out won't help. Relays and heavier wiring won't help if the alternator doesn't have enough current capacity, either - removing resistance will help the fans and other parts operate at their full capacity, but your alternator isn't keeping up with the capacity they're operating at already. I'd test your alternator to make sure it's healthy, and if so, consider upgrading to something bigger (along with heavier gauge charge wiring).
 
With that higher capacity alternator, also use a larger gage field wire and larger gage ignition wire (feed from key switch to regulator).
Or maybe better, redesign the circuit to use a relay in the engine bay. That will take a load off of the bulkhead connectors, ignition switch, field wires - none of which were intended for the extra loads being discussed (electric fan and alternator with higher field current).

Ignore the MAD advice. While it has some good points, it has a some bad design advice. It's also plain wrong about certain things - one of which is the ammeter seeing 'all current'. It usually sees zero current.

Which gets back to one of the first questions - shouldn't the stock alternator handle the electric fan? Without knowing the alternator, and without knowing the load of the fans, the answer may be no. If the fans draw 2 amps, more likely yes. If 10 amps, more likely no. A plain jane '67 A body came factory with an alternator that could support running the engine and a little more at idle. At 1250 rpm it could run pretty much everything (heater fan, 40 Watt headlights, wipers).

Replacement alternators and A/C cars had slightly higher output but at idle all alternators are at their lowest output.

IF the fans are drawing power from the engine and alternator side of the main circuit, and the ammeter indicates battery discharge, then the alternator is not keeping up.
--------------------------------------
Why adding things like fans to the battery positive can cause damage.
www.forabodiesonly.com

Current (no pun intended) consensus on 1965 ammeters/wiring

My '65 Dart has come a long way. I have added the following: Mopar electric ignition Solid state voltage regulator A relatively small stereo (10 amps) H4 headlights (9 amps) Electric fan (8 amps) Volt gauge wired directly to battery Additionally it has a very old underdash A/C rated for...
www.forabodiesonly.com www.forabodiesonly.com

Alternator output and ratings.
www.forabodiesonly.com

67 Barracuda alternator with 2 FLD connections

The PO of this car and his junkyard parts are driving me nuts. He also played with the wiring. The alt that came with the car has 2 FLD connections. Both had wires, but on this car, that doesn’t mean anything (about to go chase the wires through the harness). The rebuilt alts I see online, my...
www.forabodiesonly.com www.forabodiesonly.com
note the factory test assumes 5 amps for ignition and field
 
Last edited:
Thanks everyone for the replies. Here are pics of the voltage regulator, electric fan connector, electric fan, and alternator.

IMG_5171.jpeg


IMG_5173.jpeg


IMG_5174.jpeg


IMG_5172.jpeg
 
The fan is an SPAL electric. Here is a data sheet but I do not see the amperage. I drove the car for about 15 min and the battery was measuring 12.24 volts. I will plug it back into the trickle charger and get another reading.

IMG_5175.jpeg
 
Here is the voltage gage with electric radiator fan running with headlights off, then second pic is with electric radiator fan running and with headlights on.

IMG_5180.jpeg


IMG_5179.jpeg
 
Does anyone know how to identify the alternator p/n and electric fan p/n? The fan blade is about 14” in diameter with 5 blades and the shroud is about 22”.
 
It says use a 15 or 20 amp fuse depending on fan style , which is low. But the bottom line is the alternator is not putting out more amps than are being used at idle. Since you've already got an aftermarket cooling system you may be willing to get an aftermarket alternator that puts out what you need. Check for rpm "turn on" and amps at low rpms. Although it may be cheaper to get the proper radiator,shroud and fan assembly .
 
Here are some voltage readings:
12.57 before starting and after letting the car cool off and electric radiator fan off
12.22 when I started the car and the electric fan had not kicked on yet
12.00 with the car running and the electric fan kicked on

It is back on the trickle charger now and will get another reading at the battery in an hour or two.
 
The previous owner mentioned that the alternator was recently replaced and is high output. Any idea how to determine the specs/health of the alternator? There is a picture of the alternator above and I did not see any other markings with various angles using my camera. I will pull the alternator off and look it over more carefully if it would be helpful.
 
A typical charging system should be charging at 14.4v, so 12.4 is pretty low. Without the amperage of the fan motor, and the amperage of the alternator, it’s hard to tell whether the se components will live together. Looking at the alternator, it appears to be no more than a 48a-60a unit. A stock alternator for a 67 would be a 37a I believe. So, 48-60 is marginally better. I personally would not run a higher amp alternator without upgrading the charging system wiring, and either doing the amp meter bypass or running relays for the lights and fan.
 
That 2nd picture of the amp meter shows it running at a discharge. It should be running at a slight charge
 
DallasMan2000 said:
The previous owner mentioned that the alternator was recently replaced and is high output. Any idea how to determine the specs/health of the alternator? There is a picture of the alternator above and I did not see any other markings with various angles using my camera. I will pull the alternator off and look it over more carefully if it would be helpful.
Click to expand...
You can take the alternator off and take it to an auto parts store and have it tested. They can tell you if it’s indeed charging, and the amperage of the unit.
 
Is a standard digital multimeter like this capable of measuring the alternator amperage?

IMG_5183.jpeg
 
You must log in or register to reply here.
-

Back
Top