bloodvette80

I knew something was up when i disconnected the battery with the car running and it stalled. So many times I've removed the battery, put it in my other car and switched their positions. That means that something is wrong with the charging system. I measured the same voltage on teh battery whether the car is runnig or not. It should go up to 13.5 volts while running, then down to 12 when off. I measure 12.3 the whole time. Later that night my battery died, i lost all lights and snuck home down backlanes. With a new alternator, and draw on the battery when engine off, does anyone agree that there must be a drain somewhere, (an unfused cct), and most likely near the starter or alternator. ps I ran 4 new wires for the starter-wiring harness the other day. they are in mint shape. There is no draw when that harness is disconnected, and there IS still draw with all fuses removed. ANY CLUES? getting frustrated. :mad

Dwayne 76

Okay this is going to come accross as very newbie like and you may have already answered this question in away thats beyond my knowledge, but. Have you tried testing the output at the generator? Perhaps theres not a good connectin? bewteen it and the battery, or more specifically, a bad ground between the generator and chassis? I know that dosn't make much sense.

bloodvette80

yes and no..... yes I've tried it and no it doesn't make sense. The alternator is Bolted to the motor, ie. gnd, although 2 other ccts bolt to it and use it as a ground reference. Thanks for the suggestion, I better double check my ground. I measured 12V on both red wires (respect to gnd), and 0V on brown and black (respect to gnd). removed the terminal (red and brown wire) and measured about .5V across, if taht means anyhting. Now that i think about it, i think the heavy gauge red wire with the rubber boot is the terminal that is feeding power back into the system. i didnt check that.


[Modified by bloodvette80, 7:46 PM 8/11/2003]

page62

Correct me if I'm wrong, but isn't disconnecting the battery with the engine running a sure-fire way to fry the alternator???

stpman

The battery is only a storage device. the engine should stay running when the battery is disconnected. you need the battery in order to charge the field windings before you can get anything out of the Alt.


Steve :steering:

Dwayne 76

Okay, one more thing. This is going to sound really dumb but, the battery you put in your car isn't a new battery correct? It came from another car? I ask becasue a few years ago we were changing a battery in a car, and the damn battery wouldn't charge, and couldn't get the car started, turns out there was a black plastic cap over the negative terminal. Buch of Newfies I know :lolg: Actually that wouldn't make any sense thought your able to start the car.

bloodvette80

:lol: yea your right, that made no sense because the car started. but thanks for the suggestions none the less. More often than not some of my problems have been real dumb so if you keep throwing out dumb suggestions :

A: you look dumb &
B: I look dumb when you you find it.

keep in mind if the plastic cap WAS on the battery and it WAS the problem i would never admit it to you or anyone. :lolg:

Dwayne 76

When it comes to me and cars, its a crap shoot. :lolg:

BSeery

Yes, the heavy red wire is a direct link from the alt, back to the battery via the post on the starter solenoid.

stpman

The large Red wire is a direct connection to the battery, the wire in the plug at terminal #1 (on left looking at rear of Alt) is connected through a light or resistance wire to the ignition switch, and the wire in the plug at terminal #2 is connected to the battrey but at the horn relay.

With the key OFF there should be 12 volts at the large wire (Bat) and the wire at terminal #2. there should not be any power at the wire on terminal #1

Indicator lamp test (terminal #1)
Switch - OFF Lamp - OFF Engine - STOPPED
Switch - ON Lamp - ON Engine - STOPPED
Switch - ON Lamp - OFF Engine - RUNNING

Hope this helps

Steve :steering:

Vette-Nut

Here is the best way of checking the charging system

1) test battery by charging batt with a 2 or 10 amp charger for 1 hour. Remove charger and place a load on the batt by turning on the headlights for 2 minutes, turn lights off now test the batt with a volt meter if voltage is less then 12.30 volts the battery is toast a good batt should read from 12.50 to 12.84 volts.

2) to test the alternator start vette, turn on the headlights have some-one rev. engine above 1500 rpm now take the voltage readings at the Batt the readings must be 13.4V to 15.5v if not your alternator is toast

If every thing checks ok and your battery still dies then you have an electrical short in your electrical system.

Vette-Nut

Sorry Guy generators were used in the 40's and 50's

Dwayne 76

An Alternator is also a generator. If your alternator didn't generate A/C power which via a diode rectifier bridge, is converted to DC power, your car wouldn't run for very long. Thanks for correcting my terminology.

And, DC generators were discontinued in the '60's not the 40's and 50's :reddevil

stpman

they were used up until the mid 60's

if there is a short in the wiring it'll chew up Altenators. I had a car 15 years ago would go through an alt about every month, never did track down the problem.

A car should also run if the Altenator is good but the battery is shorted.
(I speak from 1st hand experience on that)

Steve :steering:


[Modified by stpman, 10:13 PM 8/11/2003]

Dwayne 76

:iagree:

theandies

http://misterfixit.com/alterntr.htm

Everything you wanted to know about alternators and even some you don't. :D

page62

My '72 Beetle had a generator (not an alternator). I'm not sure if the Beetle was ever fitted with an alternator (and to think they finally stopped making them the other day).

I think max output was 5 amps or something amazing like that...

70ZZ3 96LT4

I don't know if there is any difference in the wiring of your 80 and my 70 for the alternator, however check the wire from your alternator plug that has a fusable link. A alternator once burned my fusable link and the replacement alternator would not charge until the fusable link was replaced.