alternator not charging battery

[wsr1961]

I have a 440 6-pack clone with Frankenstein wiring. The battery is in the trunk. It has a toggle operated electric fan, electric fuel pump, cheap aftermarket radio, and a modern instrument panel with a retro look that I had professionally installed. (Note that my problem existed before the instrument panel was added.)

If you drive it long enough, voltage falls to under 11 volts. It improves a little with everything turned off. When the problem continued after the new instrument install, I had someone look at it, and we went with a higher-amp alternator and smaller pulley to try to increase the battery recharge.

When the engine is iding (about 750 rpm), the voltmeter shows about 11 volts. If I accelerate to 1000 rpm, it goes to 12 volts. Once I get moving, it indicates between 13 and 15 volts, depending on rpm.

Any idea why the battery may not be charging properly?

 

[KATSAAR]

voltage regulator

 

[aussiemark]

2 ideas, check the output of the alternator with a multimeter should be around 13.5v . Run the charge wire from the alternator direct to the starter motor battery positive connection and make sure this wire is the correct thickness. Is the charge wire going from the alternator to the battery positive terminal (in the trunk) now? if so this could be the problem, if you run it to the starter motor battery positive terminal you will have a shorter wire (less volt drop - the longer the wire the thicker it has to be) and one less live wire running the length of the car (safer). When I do a battery in the trunk I use arc welder handpiece cable from a welding supply store for the battery positive to starter this cable is thicker and better quality then automotive cable and I run the shortest possible negative cable. I route the cable with safety in mind and use 3/4"reticulation pipe slid over it to reinforce it in any doubtful areas.

 

[aussiemark]

Spinning the alternator faster will have no effect on output it will just cause the brushes and bearings to wear out quicker.

 

[wsr1961]

Help! I changed the voltage regulator and the issue is still there. Here' a little background. Since I bought the car, it has had the same problem. Drive it around for a while and the battery drains, then you havde to jump it off, limp home and charge the battery. One shop claimed to have fixed it, but nothing changed. A second shop went with the higher-amp alternator. Problem NOT solved. In the last month I have bought a new battery, and today I changed the voltage regulator.

Keep in mind I know very little about electrical issues. Today I traced the positive cable from the alternator, and it runs in a wire harness over to the fender well on the drivers side. It has a hoop-shaped connector, and the wire, along with several others, are all bolted onto a nut on the fender well. I removed all the connectors from the nut, scraped off some minor built up tarnish, and sprayed them with electrical connector cleaner. There is another red cable connected to that nut that runs to the starter motor. It connects to a nut on the starter motor. Another positive cable connects to the same nut, and that cable also runs back to the battery in the trunk. The starter is very hard to get to because of headers, but I was able to remove both cables from the nut on the starter, and scraped them to clean them, then sprayed them with the electrical contact cleaner and reconnected them to the nut on the starter motor. I traced one of them along the car body back to the battery terminal in the trunk. The cable seems to have been ran well, avoiding heat sources, sharp metal edges, etc. I even cleaned the battery terminal. The problem is still there.

 

[wsr1961]

When I start the engine, voltage starts at around 11 volts, climbs close to 12, then slowly drains down to between 10 and eleven.

My thinking is, if I need to run a better cable to the battery to retain voltage, I would rather just buy a battery tray for under the hood and move the battery back to its original location. What do you suggest?

 

[aussiemark]

I have done many relocated batteries and have never had a problem. If it starts ok (cranks quickly and starts easy and the lead is not hot to touch) then the main battery positive lead is good enough, the problem is probably the wire that takes the charge from the alternator to the battery (is this wire going from the alternator all the way to the battery?) if it is disconnect it and go from the alternator to the starter motor (connect it where the battery positive lead is connected) then the main battery positive lead will carry the alternator current back to the battery and because this cable is very thick you won't suffer any volt drop remember the longer the wire is the thicker it has to be not to suffer volt drop another benefit is only one live wire running back to the trunk and if you don't want you car to catch fire run a 100 amp fuse as close as possible to the battery positive terminal. You really should have @ 13.5 volts from the alternator at all times so when the engine is running battery voltage should be maintained at this level the alternator cuts in and out in order to maintain this voltage the voltage regulator sets this level but the alternator cutting in and out is what maintains it.

 

[moparleo]

I think the key word here is " Frankenstein " wiring. The original wiring from the factory was marginal when new. With the addition of an electric fuel pump, electric fan motor, aftermarket radio, trunk relocation of the battery it really is impossible for anyone online to really know how to completely fix your problems. At least you admit that you have limited electrical experience. Most people don't either. I would find a quality electrical repair shop in your area. Research them for good referrals and the Better Business Bureau. They should know how to properly deal with your problems if they are good. It is tough to buy something that somebody else has modified and try to figure out what they did. Good luck.

 

[wsr1961]

Thanks, I am probably heading in that direction. I do notice one thing. The positive wire that (I think) should run directly from the alternator to the starter motor runs instead to the fender well, where about five wires converge and are all attached to a bolt on the firewall. One of those wires continues on to the starter. I have a gut feeling that if I pick up a multimeter and test voltage at various locations, I will find correct voltage running from the alternator to the fender well bolt. I also believe that several of the wires connected to that bolt are bleeding the charge to power aftermarket add-ons, and the cable that leads from the fender well to the starter motor will show a drop off in voltage. If that is the case I probably lack the skill to reroute those wires to draw power in a way that doesn't interfere with the battery recharging, but at least I will have some idea as to how to intelligently discuss the problem with an electrician and perhaps save them some initial testing steps. I also hope to trace those smaller wires to see if they are leading to the electric fan, etc. Whether my theory is correct or not, one thing I do know is that I do not have a wire running uninterrupted from the alternator to the starter.

 

[wsr1961]

I bought a multimeter and found that the voltage at my alternator is the same as at the battery, so I am not losing power in the wiring. However, the alternator will start out around 13.5V, but after a few minutes it dips into the 12s. If I turn on electric fans and headlights, I drop to 11V pretty quickly. This is the second alternator. The belt is tight. Two wires run to it from the voltage regulator, then I have a positive wire going to the starter and a negative wire grounded to the fender well. I have cleaned all connectors, the ground is metal to metal, so I am clueless. What tells the voltage regulator to make the alternator put out more voltage? It only has the two wires running to the alternator. Does one of the wires run from the alternator to the voltage regulator to tell the regulator that voltage is dropping, and the other one run from the regulator to the alternator to tell it to kick up the volts? I am wondering if I should replace those two wires. One of them have voltage about the same as the alternator, and the other barely registers. I don;t know if that is right or wrong.

 

[moparleo]

There are 2 different electrical terms that are being used and should be defined so as to understand better what is going on. I am going to use a couple of analogies that should work fine in this case. First thing is Voltage. This term is telling you what the push/pressure of the electricity is. Think of your outside water spigot turned on, all the way up with usually a 3/4" pipe and your garden hose that is connected to it is 5/8" i.d. .
Now Amperage. Think volume. Think a 3" i.d. fire hose connected to a 4" hydrant that has the same pressure as your garden spigot. Now if the pressure is the same for both the garden hose and the fire hose, which one do you want to use to put the fire out that is burning your house ? The fire hose. Why ? Because it will flow gallons of water in the same time that your garden hose will flow pints. So the amperage or flow capacity is what we are dealing with when we add more load/electrical items to a cars electrical system. A wire is like that hose we were talking about. Or as they say, you can't put 10 lbs of *** in a 5 lb bag. The bag will bust, the wires will melt...
Point being that the electrical wiring/connectors must be upgraded first before you can flow more load through it or it will fail. One way to lighten the load is to use relays that only need enough power to flip a switch instead of carrying the complete load. Myself. Too much headache and too much at stake if I screw up. I would take it to an expert and just pay the Piper.At least you can blame someone else when things go wrong.

Or for the guy who must do it your self. Educate your self first. Go on line, buy books and read, read, read, and then ask lots of questions from people who are qualified to answer them intelligently/with actual knowledge .
Domino effect if you do the first thing wrong, every thing after it will fall as well..........

 

[AUSTA]

When you test the positive output on the alternator are you testing the ground of the alternator or the vehicle body.
To test for loss in the ground circuit place 1 probe on the alternator housing & one on the frame of the vehicle while running if you have any voltage present it would indicate a bad engine earth to vehicle frame ground.
The blue wire on the regulator is switched 12 Volts Positive it also goes to 1 brush (FLD) on your alternator
The green wire (FLD) on your alternator goes to the voltage regulator ,the frame of the regulator is connected to ground
If the 12 volts on the blue wire is low say the wire is 2 small it will heat up after a while & cause volt drop to the regulator & alternator which will in turn also cause the alternators output to gradually drop.

 

[wsr1961]

Well after about 20 hours of working on the issue I glanced at the specs on the decal under the hood. Idle should be set to 900 RPM. It was running at about 650. I found the idle screw on the six pack and idled it up. Now I am able to run with all accessories on and no apparent voltage loss. It holds its own at idle and recharges under acceleration.

However, I now have a ton of fuel in my exhaust - I have always had a fuel smell at the exhausts, but now when I accelerate that fuel is causing exhaust backfires, especially from 2000-4000 RPM. Very fast popping. It also has lost power for a few seconds a couple of times.

So, I guess its time to move on to timing, distributor cap, vacuum advance, coil, carbs, fuel pump, fuel filter, plugs, plug wires........and I know nothing about six pack carbs.

 

[AUSTA]

That would help.
I would do a compression test you could have a sticking or burnt valve causing it to fire with the valve slightly open ,also check you haven't got a couple of swapped or plug leads or the leads are too close causing crossfire