Electrical Drain

[MotoManMike]

The alternator will cause a draw if the alternator has been changed to an internally regulated one and the pin configuration not changed properly to coorelate with the new regulator T plug configuration on the back of the alternator, my car did it when I first did my alternator swap because I had my constant hot to the wrong pin. Batteries will lose 1 percent of their charge on average a day once they have been put into cycle. I love drains, its what I diagnose weekly. Most DC electrical specialist can figure it out in an hour. Find an alternator starter shop, they usually can find them pretty quick, sometimes easier than trying yourself. You are replacing alternators because everytime you drive they are trying to charge a severely discharged battery which they are not meant to do. Good luck, I suspect like they have said alternator or stereo although I have seen relays "stick" because the voltage dropped so low and welded itself inside. Just for giggles unplug the T plug to your alternator and see if that makes a change, if you can see it on the ammeter its a decent size draw. Mine had an amp and a half draw when my alternator was not wired right, it would kill it stone dead in a day.

[SteveJ]

So took out the amp, and my amp meter is still slightly below 0, and when the lights turn on it drops even further below 0...

Suggestions?

Yes, look at my previous posts.

[boosd]

I. Do have a voltage regulator, I replaced it a few years ago.

What is the correct wiring for the alternator if it has been replaced?

and are you saying if it is internally regulated that could have to do with it not charging while driving?

[SteveJ]

No, if you had an internally regulated alternator with an external voltage regulator, you would have already been experiencing an overvoltage condition. You should consider hooking up an ammeter at the battery and quantifying your battery drain.

Common conditions for a slow drain include:

1. Replacing the alternator & regulator with an internally regulated alternator in a 73 or 74. Without adding a diode in the right place, you will likely energize the coil for the fuel pump relay & drain your battery.

2. A bad voltage regulator can cause a voltage drain. Unplugging the voltage regulator and measuring the current flow at the battery would tell you whether or not that was the cause.

3. A bad door switch or glove box switch would leave the dome light or glove box light (respectively) on. The glove box light could be tricky to detect. I have see this with a dash cap. The cap kept the door from closing fully, though it seemed to latch. Since the button on the switch was not fully depressed, the light stayed on and ran down the battery.

4. Circuits added to an unswitched source can run down the battery. This can include an amplifier, the memory function of an aftermarket stereo, a remote locking system, etc.

5. The cigarette lighter is constantly powered, so anything plugged into that could be draining power, too.

A less likely culprit would be a malfunctioning horn circuit. If the horn button was stuck and someone just disconnected the horns, the relay would still be energized and could drain the battery.

If you don't know how to use an ammeter, see this link: http://www.allaboutcircuits.com/vol_6/chpt_2/4.html.

[boosd]

Is there any chance a bad fan clutch could cause problems in this area? I am also having an overheating issue at idle and some have suggested it might be the fan clutch, if i am driving and put on the blinker it will flash really slow, if i rev up the blinker starts to flash at a normal pace, lights get brighter...... As well I have had the car die on me while out driving a few times and refuse to start afterwards when i notice the lighting is fading, radio goes out, and blinker slows to a crawl when on, when I notice that the lighting begins to fade, as long as I am driving (foot on the gas) the car will keep going but if I come to a stop, or take my foot off the gas the car dies I am unable to start to due the battery being dead...

Edited August 26, 2012 by boosd

[SteveJ]

Is there any chance a bad fan clutch could cause problems in this area?

No, unless you or previous owner put in an electrical fan.

I am also having an overheating issue at idle and some have suggested it might be the fan clutch, if i am driving and put on the blinker it will flash really slow, if i rev up the blinker starts to flash at a normal pace, lights get brighter...... As well I have had the car die on me while out driving a few times and refuse to start afterwards when i notice the lighting is fading, radio goes out, and blinker slows to a crawl when on, when I notice that the lighting begins to fade, as long as I am driving (foot on the gas) the car will keep going but if I come to a stop, or take my foot off the gas the car dies I am unable to start to due the battery being dead...

That's more of a sign of a bad regulator and/or alternator (undervoltage condition). You can test the VR as I described above. The FSM tells you how to test the alternator in Section EE.

By the way, do you have good tension on your alternator belt?

Test the battery voltage with the car off. Test again with the car at idle, and test again with the car at about 2500 RPM. Tell us what the voltage is.

I suggest fully charging the battery out of the car before running this test.

[boosd]

I appear to have strayed from my original problem which is not so much a poor charge, but continuously failing alternators, I will test the alternator and regulator tomorrow, my guess is that the alternator has gone bad again. So if this is the case could a poorly grounded/malfunctioning amp be the culprit behind all these alternators going out?

http://www.autozone.com/autozone/parts/Duralast-Import-Alternator/1974-Nissan-Datsun-260Z/_/N-iopilZ93xme?itemIdentifier=334268_29983_10563_

Replacement alternator

Part Number: 14118

Weight: 12.25 lbs

Warranty: Limited Lifetime

Notes: 50 Amp alternatorPremium reman This unit has an external voltage regulator. It should always be replaced when replacing the alternator.

Alternator Diameter: 128mm Stator Diameter

Alternator Fan: External

Alternator Mounting Brackets Included: No

Alternator Output Amperage (A): 60

Alternator Regulation: External

Alternator Voltage: 12

ALSO....... Belt tension is something i am trying to figure out, belt is loose enough to turn on its side, but no further, there is little to no slack...

Edited August 27, 2012 by boosd

[Zed Head]

beerman made a good point - you might just have a bad battery. How many batteries have you replaced along with the six alternators, over the eight years?

[boosd]

beerman made a good point - you might just have a bad battery. How many batteries have you replaced along with the six alternators, over the eight years?

Battery went bad about 1 year ago, it was the 2nd battery in 8 years, and it went bad after less than 2 years, so this one is fairly new

I have a bit of new information, I was checking all of my wiring, disconnected and reconnected alternator and terminals.... I went back to start the car and the lights seemed brighter, and when i looked the the amp meter it was in the positive, with highbeams and blinker going. This lasted for a full 5 seconds or so, then everything suddenly dimmed and the amp meter dropped to negative. I did this a couple times with varying success of brighter lighting and positive amp reading for anywhere from 1 to 5 seconds before everything would dim and drop to the negative. Any new input based on this information? I have never seen this happen before....

[SteveJ]

Is it asking too much to try the tests that we suggest? It would help to know

1. How much is the current drain when the car is off?

2. Did you check for anything I did in post 16?

3. What are the voltages at the battery per post 18?

You're going all over the place. Be systematic and it is easier to track down the problem.

Edit:

I saw your post on the antenna. Check the FSM for wiring information. Also unplug the antenna and as one of your tests to eliminate the drain on your battery. A bad antenna motor/switch can drain a battery, too.

Edited August 27, 2012 by SteveJ

[Wade Nelson]

Unless you have a firm grounding (pun intended) in electricity, and know how to use your digital volt meter to measure milliamps, and haven't blown the protective fuse INSIDE your meter by accidentally measuring AMPS, I'd suggest you take your car to a qualified technician and tell him you have a parasitic drain.

I'm an electrical engineer, and, quite simply, this isn't the right territory for shade-tree mechanics. A guy who knows what he's doing can have your car diagnosed and fixed in 2 hours or less labor.

50mA or less is an acceptable drain on a battery --- keep alive memory inside the radio, etc. Anything over that and you have a problem. A 100mA drain will flatten a battery in 3wks to a month. 200ma, 2 weeks. 300ma (typical courtesy lamp bulb) one week or less. Newer cars pull 15ma or less when everything's off.

If you leave a door open, hence courtesy light, when measuring your battery drain, you're likely to poof the fuse in your meter. Like I said, diagnosing and fixing parasitic drains isn't territory for novices.

Your alternators are failing because they're having to work too hard, constantly recharging flat batteries. They are a symptom, not a cause. The cause is a parasitic drain.

Never "go for a drive" to recharge a flat battery, unless you like buying alternators. Use a professional recharger, or keep your car on a trickle charger. All the alternator is DESIGNED to do is to "top up" the battery after cranking, and to supply enough current AT NIGHT to run the lights, etc. without the battery getting drained.

You've already paid far too much buying batteries and alternators. Now's the time to hire a pro and get the problem fixed, IMNSHO.

[SteveJ]

Unless you have a firm grounding (pun intended) in electricity, and know how to use your digital volt meter to measure milliamps, and haven't blown the protective fuse INSIDE your meter by accidentally measuring AMPS, I'd suggest you take your car to a qualified technician and tell him you have a parasitic drain.

That's quite an extreme stance, Wade.

I am also an electrical engineer, and I learned how to measure current in a high school shop class. It's not rocket science. Start at the highest scale and slowly move down. Most inexpensive multimeters have a 10A range. That is more than sufficient for a car that is off.