Beetle Battery Not Charging - Different STYLE GENERATOR

[iboesen]

Hello everyone,

Iv been searching up and down and looking through the forums and I cannot seem to get a concrete answer to this issue I am having with my charging system on my bug.

Ill try to show you guys in as much detail everything that I have found so far.

Currently when I have my bug running, the battery remains at the current voltage it was at while not running. Somewhere around 12V

I am running tests on my generator and this is what I have found so far.

Here is my set up, - which to me looks very different then the ones that I see on the forums.

Now, the voltage regulator I have in my bug is a motorola made regulator. I found a diagram relating it to the genereator that is already in the bug. Here is the diagram so this may make more sence to you guys.

So. ------------ This is what iv found thus far.

WITH THE BUG RUNNING ---->

When i have to beetle grounded on the DF Terminal-
And the volt meter plugged into the D+ i am getting about .5V with no change when I increase RPM.

Now one question I have is when I try this does it matter if I have the battery lead connected to the generator or not?? I have tried it both ways and I see no change in Voltage. See here \/ \/ \/

I am not getting any reading obviously when the car is shut off.

I guess my biggest question is, am I doing these tests correctly?

I have my volt meter grounded when i test the D+ side.

My biggest confusion is that this motorola voltage regulator and generator plugs dont look like anything else that I have encountered on the forums.

Anyhow let me know what you guys think, and input at all will be helpful.

Thanks!!

[busdaddy]

Until you have all the wires connected don't expect much of anything to happen on an alternator, they need external voltage to begin making a charge.
That diagram you have is correct, lets see the regulator.
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[Danwvw]

Ok that's the first Alternator that ever came on VW's It came out in late 1973 and 1974 then VW went to Bosch alternators.
The Motorola Alternator that this is is a very good alternator it just needs an external voltage regulator to work. It's hard to say what is going on here. It's rare to find one still in service.

The good news is this old Alternator can be rebuilt with a $2 brush set from the hardware store and some $5 bearings that you can find on e-bay.

Most likely what is happening with yours is the Voltage regulator is bad and the Alternator needs a brush and it needs it's Positive post cleaned both inside it and outside there. Also the screw inside in the back end of the alternator that grounds the Negative inside the alternator is probably rusted and not making a ground connection.

Start first with changing the voltage reg and the brushes but you will need to pull the alternator to get to the other parts.

Voltage Regulator ACDelco695 is what I think I used on my Motorola Alternator.

If you could get the 36mm fan nut in the intake to the fan loose. Then It's pretty easy to remove the Alternator and an Alternators bearings can be changed with hand tools.
VBX 6202,
VBX 6203
These bearings as well as the brushes are available on e-bay.

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[ashman40]

[iboesen]

Hey guys thanks for the updates.

I really appreciate all the responses that I have received from you all.

This is what I have found so far.

In response to the last post - reading through the article I have checked and It looks like my alternator light is NOT on at all.

I went ahead and checked the fuses and it was missing the fuse. after replacing the fuses it looks like the light is still off - but the oil check light did come on so I know that the fuse did fix sometthing.

I checked the bulb and it appears to be in good standing, I even swapped it with the oil check bulb and it worked for the oil light. so i know it isnt the bulb.

I went ahead and checked continuity for the blue wire that runs from that alternator check light and it seems to be in good standing as well.

My question is - where is it supposed to be getting power from when I turn the key to the on position?

is there supposed to be voltage coming from the D+ terminal on the alternator that supplies power to the 12v indicator light?

From what I read the light is supposed to be ON when car is on and OFF when car is running. As of right now it is on regaurdless.

I also checked continuity from the B+ wire that goes on the alternator to the plug that goes into the regulator and it looks sufficient/

any thoughts guys??

thanks for the help!

[Danwvw]

The alternator light gets it's power from the (key on position) from the ignition switch. Same 12 volts that runs the oil light and others. It finds a ground at the alternator when the alternator is not charging. No alternator light at all even with the engine stopped says the alternator D+ is open circuit. Could be a broken wire or internal at the alternator. it's circuit completes through the diodes through the staters to ground. It could be the internal ground. I am not sure but It could be D- is not finding ground. Maybe it's a worn brush? If you pull those 2 screws and remove the brushes and have a meter you can check the armature etc..
See Alternators/Generators

here. Internal wiring for the Motorola Alternator:

The internal ground is between the diode array heat sink and the housing of the alternator and it is where there is a counter sunk flat screw. It's likely chroaded. This little screw mounts and holds the diode ground heat sink there and the other mount point that likely is rusted is the positive post where it is press fit into the diode positive heat sink or even just at the terminal nuts.

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[ashman40]

This thread has some great pics thanks to Danwvw!

The thing to remember when it comes to the Gen/Alt light in the speedo... it turns ON when current is flowing thru the bulb. That may seem obvious, but it is less intuitive when I mention that the Gen/Alt bulb may have 12v+ but be OFF. This is because it is possible to have voltage at a point in a circuit WITHOUT having current flow (or not enough current flow to light the bulb).

The reason you have voltage is because you have a difference in "potential" between two ends of a circuit. This difference allows current flow. Most circuits have ground (0v) at one end and battery positive voltage (12v+) at the other. The difference is 12v and current flows between the two.
This is analogous to having water pressure (voltage) in a faucet. When you open the faucet the pressure forces the water out into the air and you have flowing water (current flow). The amount of water that flows out is analogous to the amount of current.
Using this analogy, what happens if you connect a hose between two separate faucets and open both?

Is there pressure (voltage) in the hose and faucets? Yes. So there is voltage.
Is there water flow (current flow)? No. So there is no current flowing and any device like a bulb installed in the wire would NOT turn ON.. because the bulb lights up NOT because of voltage but because of current flowing thru it.

Looking at the pic above... when you turn the ignition ON you close the circuit allowing current to flow down thru the "Lamp" to ground on the other side. Some of this current flows thru the field coil (FIELD (Rotor)) creating a magnetic field inside the rotor. Note that this magnetic field is created by "flowing current" just as the bulb lights up with flowing current.

Once the alternator starts spinning, the spinning rotating field coil generates a charge in the stationary stator. A small part of this output passes thru the lower trio and feeds 12v+ out of the D+. Where you previously had current coming from the ignition flowing INTO the D+ terminal, you now have (around) 12v+ flowing OUT of the D+. This creates backward current flow TOWARDS the ignition switch. At the Lamp you have 12v+ coming from BOTH directions. Like the two faucets connected together, there is no longer current flow thru the Lamp. The Lamp turns OFF even through there is voltage on both sides of the lamp. The benefit here is that the voltage coming OUT of D+ is flowing down thru the field coil and maintaining the magnetic field that was initially created by the ignition switch current. The alternator is now self-sustaining.
So you see, the alternator initially needs voltage coming from the ignition switch thru the Lamp to start charging. Once the alternator is spinning and has started to produce its own current it is self-sustaining and maintains the field even if the voltage from the Lamp/ignition stops. But if there is no initial current flow from the Lamp to create the magnetic field in the field circuit, the alternator never starts charging... even if it is in 100% working order. This need for a small amount of current to get the alternator charging is called a "tickle charge".


TEST: With the ignition ON and the engine NOT running, disconnect the wires from the external regulator and with a jumper wire ground the blue #61 wire. This will complete the Lamp circuit and the Gen/Alt lamp in the speedo should turn ON. This shows the circuit is good up to the point that you grounded.
With a multimeter, test the green field wire in the wire harness that runs to the alternator (or test the DF terminal on the alternator) for ground. While the alternator is not spinning this terminal should be grounded at the internal end of the field coil. If this is not grounded there is an OPEN circuit inside the alternator. It will need to be rebuilt. If this is the case, I'd recommend you either find a local shop to rebuild your alternator, or buy a rebuilt INTERNALLY regulated alternator and get rid of the external regulator.
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AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[btracy]

i needed this post .thanks

[btracy]

where does that black wire go thats with the thick red one?

[cletus_zuber]

btracy

In your picture posted elsewhere, the black wire goes to a radio noise suppressor, you can throw it away if you want.

In the pictures in this thread it goes to the diagnostic socket, it can be eliminated with no worries.
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