Electrical Help

[PhillipM]

My alternator is not charging the battery. I think I have been facing this issue for a very long time. I had this issue during homecoming. Today I put the second Alternator and voltage regulator on the car, still same issue.
This is what I have done so far.
1. New Alternator
2. Had the Advance Autoparts test the new alternator before I took it home.
3. New Regulator
4. Tested new alt/regulator with a volt meter and had Advance Auto parts test it as well. This is after I excited the alternator. Between 2000 and 2500 rpm, no voltage increase.
Could I have a grounding issue?
If I take a voltmeter and remove the red wire from the alternator, will I see voltage if I reconnect battery? I am trying to determine if I have a broken wire.
I am trying to determine the best troubleshooting techniques. Other that this issue the car runs great. Also, no blown fuses and all other electrical components work fine.
Phillip

[Aggressor]

Phillip
1st Refresh our memories as to what alternator and regulator configuration you are running.

Check for grounding issues first and then check the continuity of wire connections.
Also if you have aluminum mounting brackets for your alternator mounts - especially billet types - you may have to run a separate ground cable to the alternator housing. I worked on a customer's 53 Chevy street rod a few months ago. The battery terminal showed 12.5 volts prior to starting, jumped to 13.7 when the excitor kicked in, and then steadily fell to 10.5 on a short hop around town. About made me nutz until I called Powermaster and the tech asked about the mounts for the alternator. Separate ground installed - no more problem. Also if you're running a separate regulator mounted on glass, ground the housing to the frame as fiberglass is even a much worse ground than aluminum. Make sure your engine is grounded to the frame also.

- Geary

[Slither]

if you have aluminum mounting brackets for your alternator mounts - especially billet types - you may have to run a separate ground cable to the alternator housing. I worked on a customer's 53 Chevy street rod a few months ago. The battery terminal showed 12.5 volts prior to starting, jumped to 13.7 when the excitor kicked in, and then steadily fell to 10.5 on a short hop around town. About made me nutz until I called Powermaster and the tech asked about the mounts for the alternator. Separate ground installed - no more problem. fiberglass is even a much worse ground than aluminum.

- Geary

Not sure I follow this... aluminum is an outstanding conductor, commonly used in the power-distribution industry. In fact, my house runs on it... underground aluminum cables. Most of yours do as well! It seems that paint or some other non-conductive bushing would be the cause of this, rather than an aluminum bracket... unless maybe there was some serious corrosion at the mating surfaces.

The aluminum bracket is not the ground, but becomes part of the ground node along with the engine, frame,and anything else connected to that part of the circuit and the negative battery terminal. Such is the wire that you used to bypass the alternator bracket.

What did the tech say caused the issue? Is the billet stuff a non-conducting alloy? That would do it...

[mkassab]

Hi Phil.... I've heard of this problem before. In fact, I already purchased a ground strap for the Cobra build.... (from engine to frame).... here's a link. http://www.summitracing.com/parts/TAY-148014/
Even if this isn't the issue, it sure can't hurt. Mark

[JeepSnake]

Not sure I follow this... aluminum is an outstanding conductor, commonly used in the power-distribution industry. In fact, my house runs on it... underground aluminum cables.

Paul, you are right: aluminum is a fine conductor. But, the sticking point is that aluminum sucks in regards to making a good connection to it. It is extremely reactive - it is more quick to oxidize than iron. Every piece of exposed aluminum in your engine compartment has a thin layer of non-conductive aluminum oxide on it; if that's not penetrated in the connection, no conductivity. (Conversely, this thin oxide layer protects the aluminum underneath; rust does not do this for iron. That's why an iron piece will rust away faster, even though it's not as reactive as aluminum.)

And then there's the issue of keeping the connection once you've established it. Remember the fiasco of aluminum building wire in the '70s? The connections loosen up over time, corrode, build resistance, heat, arc, burn the house down... I know the industry tried various types of special connectors and even copper-plated aluminum wire in an attempt to get the connections to last over time, all without much success.

You service drop cable (about a 40% chance it is Southwire cable manufactured on a production line that I installed, BTW! Please go buy more! We need the business!) is indeed aluminum, but you'll see that it stops at your breaker box. From there on you'll have copper. You'll also see that where the aluminum is lugged into the box that it has gobs of conductive joint compound on it to increase condutivity, lube the lugs, and protect the connection from corrosion.

So, even though the aluminum itself is great, the various intermediate connections can kill you. A ground wire straight to the alternator case is an easy way to avoid a lot of potential headaches caused by the connections. (Also, always use a serrated lock washer for your ground wire connections - you know, the washers that look like a Skil saw blade. At the alternator case, these will cut through the oxide layer; at the frame, they'll cut into the steel for a better connection as well.)

[mkassab]

Phil, I agree with all the above on Alum. and Oxidation. So her's what I would recommend. Go to Lowes or Home Depot electrical section and buy a small tube of Ox-Gard. This is "grease" like stuff that prevents alum oxidation. Then clean any area you have alum connections, add OX-Gard, then clamp tight. I'd also run a seperate ground wire from the alternator.... I'm just not sure the gauge size you should use? My guess would be is to use the same size as the copper + (positive) coming from the alternator. One thing I do know is too big is much better than too small.

Mark

[mkassab]

Phil... I may missed it, but did you have your battery checked? Maybe something wrong on that end?

[JeepSnake]

Good point on checking the battery, Mark.

Phillip, do you have an Optima? They had a rash of quality control problems a few years ago. Thought they would have them ironed out by now, but you never can tell.

[PhillipM]

Ok, here is what I have done so far and will do over the next day or so. I did a voltage check at the battery and it read 12.50 volts. I disconnected the red wire on the alternator, reconnected the battery and at the alternator it read 12.50 volts.

Where the ground was connected did have a lot of powder coating and I removed it to get a better ground. When I re-tested the alternator with the car running, output was still not charging. I plan to move the ground to a better spot over the weekend.

Alternator - Standard Ford 60amp - (Part# P7078)
Voltage Regulator - F7078
Battery - Optima Red top

I will have the alternator and battery re-tested this weekend.

Phillip

[mkassab]

Phil, What's the latest status on your electrical situation?

Mark

[Aggressor]

Conductivity.

Silver, Copper, Gold are the best in that order. Aluminum is listed as good and has about 1/2 the conductivity of copper. Relative conductivity ratings for aluminum alloys are 30-50 verses 89.5-100 for copper alloys.

Housing codes actually started to change in the 1950's due to aluminum oxide related house fires. This yielded the all-copper home statutes in place today.

- Geary

[Slither]

Conductivity.

Silver, Copper, Gold are the best in that order. Aluminum is listed as good and has about 1/2 the conductivity of copper. Relative conductivity ratings for aluminum alloys are 30-50 verses 89.5-100 for copper alloys.

Housing codes actually started to change in the 1950's due to aluminum oxide related house fires. This yielded the all-copper home statutes in place today.

- Geary

Yes, but y'all will notice that I mentioned the words "underground" and "corrosion" in my initial response. I did not suggest that aluminum was used inside the house, merely that it is an outstanding conductor, which it is.

It may help to look at the inverse property of conductance. The inverse of conductivity is resistivity, i.e. from which we derive resistance. For Cu it is on the order of 1.6 and for Al it is 2.6, corresponding to what Geary suggests (with the exception that his Cu value is inflated... conductivity for Cu should be around 60 - 61, unless he is looking at percentages as related to Cu, which could be the case).

At first glance 1.6 and 2.6 seems like a large difference. However, it is important to examine the units associated with these numbers. That would be 30 - 50 Mega Mhos (Mega Seimans) conductivity for Al and 60 - 61 Mega Mhos (Mega Seimans) for Cu, corresponding to 2.6x10E-8 ohm for Al (read as "2.6 times 10 to the minus 8"), and 1.6x10E-8 ohms for Cu (read as "1.6 times 10 to the minus 8").

How many of you have a meter that can detect the difference between 0.026 micro ohms and 0.016 micro ohms, which also can be read as 26 nano ohms and 16 nano ohms, respectively?

So the choices for corrosion are conductive grease, as used in the power industry, or a separate grounding conductor to bypass the bracket corrosion... no big deal either way.

[RJacobsen]

Yes, but y'all will notice that I mentioned the words "underground" and "corrosion" in my initial response. I did not suggest that aluminum was used inside the house, merely that it is an outstanding conductor, which it is.

It may help to look at the inverse property of conductance. The inverse of conductivity is resistivity, i.e. from which we derive resistance. For Cu it is on the order of 1.6 and for Al it is 2.6, corresponding to what Geary suggests (with the exception that his Cu value is inflated... conductivity for Cu should be around 60 - 61, unless he is looking at percentages as related to Cu, which could be the case).

At first glance 1.6 and 2.6 seems like a large difference. However, it is important to examine the units associated with these numbers. That would be 30 - 50 Mega Mhos (Mega Seimans) conductivity for Al and 60 - 61 Mega Mhos (Mega Seimans) for Cu, corresponding to 2.6x10E-8 ohm for Al (read as "2.6 times 10 to the minus 8"), and 1.6x10E-8 ohms for Cu (read as "1.6 times 10 to the minus 8").

How many of you have a meter that can detect the difference between 0.026 micro ohms and 0.016 micro ohms, which also can be read as 26 nano ohms and 16 nano ohms, respectively?

So the choices for corrosion are conductive grease, as used in the power industry, or a separate grounding conductor to bypass the bracket corrosion... no big deal either way.

corresponding mega nano seimans micro converse Cu .... Huh

[Slither]

Come on Rod, get with the program! Don't you speak geek?