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Michaellatini
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Joined: August 08, 2004
Posts: 227
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 Posted: Fri Jul 25, 2025 5:01 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Thank you for the response, Ashman. I put on the trickle charger for now till Sunday. I'll post an update on Monday.
M |
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Michaellatini
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| Posted: Mon Jul 28, 2025 4:18 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Okay, so with the battery topped off when starting the engine the gen light stays lit until it is revved past 1500rpm. Not a good thing for a cold motor. Had this problem originally before adding the LED into the mess. After revving the light does go out completely. I still have the 3 relays connected to the battery terminal on top and that could be why I am not seeing more than 12.9v at best from the alternator. When it gets really hot it drops to 12.5-6v without any accessories on. I will move the connection for the relays but, it will be connected to the wire going to the headlight switch before the split of the wire heading to the starter. I hope this will increase the output voltage and turn off the gen light without revving.
Thanks again,
M |
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Michaellatini
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| Posted: Fri Aug 08, 2025 12:41 pm Post subject: Re: Crazy Electric Issue/Alternator |
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So, finally I got the relays connected to the wire going to the headlight switch as shown in the picture below.
The gen light is still on upon startup and goes out after passing 1500 to 2000 rpms with a quick step on the peddle.
Will adding a second bulb or resistor in series with the currant bulb possible fix this issue? If so, should the second bulb or resistor be before the current bulb or after?
Thank you in advance,
M
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ashman40
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Joined: February 16, 2007
Posts: 16657
Location: North Florida, USA
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| Posted: Fri Aug 08, 2025 2:08 pm Post subject: Re: Crazy Electric Issue/Alternator |
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| Michaellatini wrote: |
| Okay, so with the battery topped off when starting the engine the gen light stays lit until it is revved past 1500rpm. Not a good thing for a cold motor. Had this problem originally before adding the LED into the mess. After revving the light does go out completely. |
Humor me...
Using your VM, measure voltage at the following spots BEFORE and AFTER you rev the engine to get the GEN lamp to go out...
- At the fuse where the bottom three speedometer indicator lamps get their power (fuel gauge fuse?). It will be one of the fuses powered by the ignition switch. If the voltage at all of these are the same it doesn't really matter which one you use.
- At the battery posts and battery terminals.
- At the B+ stud on the alternator. This should be nearly the same as the battery post before you start the engine. The voltage reading here should go UP once the alternator is charging.
- At the D+ wire on the alternator. Before the engine is running this will be the voltage coming from the fuse box that passes thru the GEN lamp. It may be quite low. Once the alternator starts charging the voltage reading here is the output of D+ which should be nearly the same as on the B+ terminal.
- On either side of the 2W GEN lamp bulb.
The voltage at the battery posts/terminals is a view of whether the battery is charging, or not. The initial battery voltage should be 12.6v (100% state of charge) with the battery at rest. When you turn the ignition switch ON and devices start to pull current from the battery the volatge reading should drop a little (say to around 12.0v).
The voltage at the B+ terminal of the alternator is a measure of the output of the alternator to power the electrical system and recharge the battery. The VR in the alternator should vary the output voltage to control the charge rate of the battery. 13.8v should be a min reading at B+ but often the voltage reading here could be in the uppper 14s of volts. If you get a higher reading at B+ but only see 12.6v at the battery posts it could mean something is pulling current away before it reaches the battery.
The voltage readings at the GEN lamp will give you an idea WHY the lamp remains ON even after the engine is running? For example, on the fuse box side of the GEN lamp you should get the same voltage reading as the fuse box. On the D+ side of the bulb the voltage reading will be lower until the alternator starts charging.
Once the engine is running, D+ should output voltage on this side of the GEN lamp and you should get close to 12v on both sides of the bulb (as long as the voltages are within 2v of each other you are good). 12v+ coming from the D+ terminal towards the GEN lamp turns the GEN lamp OFF. If you still get 12v on the fusebox side but much less than 12v on the D+ side you know the alternator is not outputting enough to turn the GEN lamp OFF. Rev the engine and check voltage reading once more. If the GEN lamp goes out it is because the D+ is now outputting enough voltage/current to balance the 12v coming thru the GEN lamp.
I'm trying to understand if the GEN lamp remains ON after stating because there is NOTHING coming out of D+ (no voltage above ground) or if there is NOT ENOUGH voltage coming out of D+... until you rev the engine.
| Michaellatini wrote: |
| I still have the 3 relays connected to the battery terminal on top and that could be why I am not seeing more than 12.9v at best from the alternator. When it gets really hot it drops to 12.5-6v without any accessories on. I will move the connection for the relays but, it will be connected to the wire going to the headlight switch before the split of the wire heading to the starter. I hope this will increase the output voltage and turn off the gen light without revving. |
Do you have a good idea how much power/current these relays are drawing from the battery? It may be possible the relays are pulling so much current that it causes the voltage reaching the battery to read low (below 13.8v). Check that the alternator B+ output voltage reading is high but the voltage reading at the positive terminal is lower. Can you disconnect/disable some of the relays while the engine is running to reduce anything pulling current way from the battery? Does the voltage reading at the battery terminals go up to where the battery is charging?
Create a jumper wire with a 2W bulb inline. Disconnect the D+ wire at the alternator and install this wire+bulb between the ignition coil (+) terminal and the D+ terminal of the alternator. This is functionally the same as the dash mounted GEN lamp. Does this GEN lamp function the same as the one you have in the dash? Of does it immediately go OFF once the engine is running? If it doesn't have the same problem... you have to ask, what is different? Take voltage readings to try and understand.
Is the 2W bulb you are using for the GEN lamp the stock VW speedometer bulb or some off the shelp 2W/12v bulb? Everyone calls the speedometer bulbs 2W but I'm not sure I have ever seen them rated as 2W/12v.
Adding anything to the D+ wire will change the power flowing into the D+ terminal of the alternator. You probably don't want to do anything that will REDUCE the power flowing into D+.
Here is what I suspect is going on with your alternator...
Power flowing thru the GEN lamp and into the D+ terminal is enough to get the alternator charging, just barely. At idle, the minimal charge results in insufficient output from the alternator on B+ and D+. You should see this as low voltage readings at B+ and D+ immediately after you start the engine and the GEN lamp is still ON, before you rev the engine.
When you rev the engine the alternator increases the output on both B+ and D+. Higher voltage on D+ means more power into the field coil, which increases the output form both B+ and D+... eventually D+ output voltage is high enough that the GEN lamp turns OFF and the output at B+ and D+ are enough to start charging the battery. Once the GEN lamp is OFF, and you rev the engine to 2100rpm or more, what is the voltage reading at B+ and at the battery terminals? It is not so important that the alternator is charging the battery at idle, but once you start driving down the road and the engine rpms are up (2100rpm+) the alternator should be outputting enough voltage (13.8v+) to recharge the battery.
All of this is a guess. Some of the requested voltage readings above could confirm if this is happening, or it is something else.
Question: I think you said one of the relays powers the AC. Is that the AC blower under the dash? Or are you running an electric AC compressor? What other high load devices are you running off the battery? I'm just wondering if your are over taxing your charging system?
_________________
AshMan40
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'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!} |
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Michaellatini
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| Posted: Fri Aug 08, 2025 2:46 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Thank you, Ashman for all of the information. I will do all of what you instructed on Sunday and post a response. This car doesn't have the original speedo in it so, I just have the single bulb at the end of the blue wire from the alternator then connected to the fuse box on the ignition switch. The only relay that is turned on during startup is the one for the ECU. The other two are for the A/C fan and compressor and the cooling fans for the A/C evaporator.
M |
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Michaellatini
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| Posted: Mon Aug 11, 2025 11:55 am Post subject: Re: Crazy Electric Issue/Alternator |
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Hello Ashman,
Here are the results.
So, based on what you said above, the alt. will not put out more than 1.43V at startup. It's a $250 Pertronix, 90amp because I was leery of aftermarket.
Could it be the VR inside the alt?
IT JUST HIT ME! Is the problem in the wire from the lamp to the alternator and that's why there is only 1.43v at the alternator???
As for the one relay that turns on the ECU could I disconnect it and connect it to another battery not in the car, just to see if that would allow the alt to kick out more V on startup?
Installing another bulb between the D+ post and the wire to the post, no changes and adding bulb to the wire from the fuse to the wire from the current bulb, no changes. Second bulb does not light on the fuse test.
Lamp still stays lit until hitting 1500 to 2100 rpms. I even hooked the wire from the bulb directly to the fuse bypassing the other triggers that turn on when starting the car. No change.
The 2W bulb has, 14.2 ohms of resistance if that helps.
Thank you in advance again,
M |
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ashman40
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Joined: February 16, 2007
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Location: North Florida, USA
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| Posted: Mon Aug 11, 2025 3:18 pm Post subject: Re: Crazy Electric Issue/Alternator |
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| Michaellatini wrote: |
Here are the results.
So, based on what you said above, the alt. will not put out more than 1.43V at startup. It's a $250 Pertronix, 90amp because I was leery of aftermarket. |
You misunderstand the GEN lamp and the D+ circuit. With the ignition switch ON before you start the engine, the alternator is not outputting anything. The current is coming from the fuse box thru the GEN lamp and grounding thru the D+ terminal of the alternator. I expected the voltage reading on the D+ side of the GEN lamp to be low. And it is, only 1.43v. This is low, maybe too low?? The GEN lamp is consuming the current coming from the fuse box and turning it into light/heat. After the current passes thru the GEN lamp there is less so the voltage reading drops off by the time it reaches the D+ terminal of the alternator. The alternator D+ is NOT adding any current to this circuit because the alternator is not yet outputting a charge. You know this because the GEN lamp is still ON. The question is whether the alternator is not charging because there is insufficient power coming thru the GEN lamp, or there is a problem with the VR. I don't know if there is a specific minimum voltage reading at D+ before the alternator VR starts charging??? This is sometimes called the "tickle voltage" as it gets the alternator to start charging. Is 1.43v too low? Maybe someone who rebuilds these units has an answer?
Did a quick search and it suggests the input "tickel voltage" for D+ should be close to battery voltage (12v). If so, your 1.43v is too low. But if this is the case, how does your alternator START charging unless the voltage increases as you rev the engine?
| Michaellatini wrote: |
| Could it be the VR inside the alt? |
Looking at the D+ and B+ voltages while the engine is running and the GEN lamp has turned OFF indicating it is charging... 14.01v and 14.09v are okay readings (not great). But here's the question... where is the current going such that the voltage reading is only 13.58v when it actually reaches the battery?? It is not a bad wiring/high resistance problem because with everything OFF the voltage at the battery and B+ are the same. This indicates a near zero resistance in the B+ wire. If there was high resistance in the B+ wire the voltage readings would be lower at B+ than at the battery terminal with everything powered off, but its not.
Is your alternator charging? Yes, once the GEN lamp goes out. Is it charging enough? Barely. The voltage readings at the battery and fuse box are up from the battery reading alone. This says the charging system has increased the voltage across the entire system. The battery itself is only outputting 12.7v and is actually pulling the system voltage down some. If the alternator VR was not working you would only have a reading of 12.7v or less across the whole electrical system.
| Michaellatini wrote: |
| As for the one relay that turns on the ECU could I disconnect it and connect it to another battery not in the car, just to see if that would allow the alt to kick out more V on startup? |
You are focusing too much on the GEN lamp remaining ON until your rev the engine. Once you rev the engine and the GEN lamp turns OFF it indicates the alternator is now charging. Your voltage measurements indicate it IS charging with an output of 14v+ but what is not clear...
- Is the voltage difference between the B+ and battery post (0.43v loss) caused by a lack of current output from the alternator? Is it not charging ENOUGH?
- Is the voltage difference caused by something drawing too much current from the B+ circuit before it reaches the battery?
I recommend you disconnect any high amp draw devices and see if you can get the battery post readings to get above 13.8v? 13.58v is marginal. It will recharge the battery if not slowly. Can you get the alternator to output more than 13.58v if you raise the rpms above 2000rpm and hold it there? Ideally, your charging system recharges the battery WHILE you drive, not while you are idling.
| Michaellatini wrote: |
| Installing another bulb between the D+ post and the wire to the post, no changes and adding bulb to the wire from the fuse to the wire from the current bulb, no changes. Second bulb does not light on the fuse test. |
Adding a second bulb inline of the existing GEN lamp only reduces the current that will power the field coil in the alternator... making it harder for the alternator to start charging. Once it does start charging and the GEN lamp goes out it makes no difference. If the bulbs are slightly different in their wattage, the lower wattage bulb will light while the higher watt one will remain dim or not light at all. A 2W bulb will only flow 2W. If you put it in series (in line) with a 5W bulb the 5W bulb will only see 2W flowing thru it and may not light up at all even though current if flowing thru it. There is just not enough current to get the filament to burn.
| Michaellatini wrote: |
Lamp still stays lit until hitting 1500 to 2100 rpms. I even hooked the wire from the bulb directly to the fuse bypassing the other triggers that turn on when starting the car. No change.
The 2W bulb has, 14.2 ohms of resistance if that helps. |
Rather than using a power source all the way up front, have you tried a power source closer to the alternator? For example, putting the 2W bulb between the ignition coil (+) and the D+ terminal? You could even use the B+ as a 12v+ power source, placing the 2W bulb between B+ and D+. Leaving it connected only for testing.
If placing the 2W bulb on a short length of wire results in the normal behavior of the alternator charging as soon as the engine is running (voltage on D+ and B+ go high) then you know it is a problem with the wire or fuse box power source. If the alternator behaves the same (only turning the GEN lamp off when you rev the engine) you know it is an alternator issue.
Have you tried measuring the voltage on D+ as you slowly raise the rpms? Does the voltage reading remain 1.43v all the way to 1500rpm and then jump to 14v+?? Or is there a gradual increase in the D+ voltage reading? Until the alternator is charging, the voltage reading on D+ is coming from the fuse box. Could the voltage be too low to kick the alternator into charging? I noticed you have a nearly 1.0v loss between the battery at rest and the fuse box voltage with the ignition switch ON. That's a rather large voltage loss. This means there is less than 12v making it to the GEN lamp and even less passing thru it to reach the D+ before cranking.
Starting at the battery, take voltage readings at the following points. There should be small voltage losses along the way but I would normally expect 12.0v would make it to the fuse box once passing thru the ignition switch. Where is the bulk of this voltage loss coming from? A common source is the ignition switch internal contacts are burnt and carbonized creating high resistance thru the contacts. If the input voltage on the red #30 wire at the ignition switch is much higher than the output voltage of the black #15 wire you know the cause is internal resistance of the switch. Also look for dirty terminals along the path from the battery to the ignition switch to the fuse box. Clean all of these connections and you may be able to get back enough volts to make a meaningful difference in the voltage that makes it to the D+ terminal of the alternator.
Your alternator is not working normally but it is charging. The way I see it you have two problems:
1) The charging system does not start charging until 1500rpms+
2) Once it starts charging, it produces a minimal level of charge 13.5v at the battery. This is above the default battery charge of 12.6v so DOES charge the battery but it may not be outputting the full 90A capacity the alternator is rated for.
While I agree the charging system SHOULD start charging w/o having to rev the engine... this could be indicating a troublesome VR inside the alternator. You still need to clean up the contacts and see if it is not a wiring/connector problem reducing the voltage that eventually makes it to the D+ terminal. If it is a wiring/resistance problem, connecting D+ directly to B+ with an inline 2W bulb as a mock up of the GEN lamp should produce different (more desireable) results. If connecting it this way results in the charging system working as soon as your engine is running... you know there is a problem in the GEN lamp/D+ wiring. If there is no change and it still doesn't turn out the GEN lamp until you rev the engine... then suspect your VR.
_________________
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!}
Last edited by ashman40 on Mon Aug 11, 2025 3:31 pm; edited 1 time in total |
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Michaellatini
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Joined: August 08, 2004
Posts: 227
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| Posted: Mon Aug 11, 2025 3:31 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Thank you, Ashman, for all of the explanations. I will do as suggested and let you know. The ignition switch is the original part from 1968 so I will try the bulb across the B+ to D+ and see what that does first. Then test from there.
M |
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ashman40
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Joined: February 16, 2007
Posts: 16657
Location: North Florida, USA
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| Posted: Mon Aug 11, 2025 3:37 pm Post subject: Re: Crazy Electric Issue/Alternator |
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| Michaellatini wrote: |
Thank you, Ashman, for all of the explanations. I will do as suggested and let you know. The ignition switch is the original part from 1968 so I will try the bulb across the B+ to D+ and see what that does first. Then test from there.
M |
I updated my post. Did some searching and it suggests that the "tickle voltage" from the GEN lamp that reaches the D+ should be close to "battery voltage" (12v). If this is true then your GEN lamp output of 1.43v is not producing enough voltage to get the alternator to start charging.
I don't know if I would recommend directly connecting D+ to a 12v power source, but you could try a 5W parking light. A 5W bulb only allows 5W to flow thru it. This would be 2.5x the power of a 2W bulb but still a limited current flow thru the field coil.
Like I suggested, first try the 2W bulb between B+ and D+ and see if it makes a difference.
_________________
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!} |
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Michaellatini
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Posts: 227
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| Posted: Tue Aug 12, 2025 10:32 am Post subject: Re: Crazy Electric Issue/Alternator |
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Hello Ashman,
Thank you so much for all of your help with this issue.
Here are the results.
Yesterday I checked the voltage at the D+ while the wire was still connected to the alt terminal. Today with it disconnected and the key on engine off, 11.27 volts from the fuse box.
With the 2W bulb connected directly from D+ to B+ the bulb stays lit when starting the engine and goes out when it is revved above 1600 or so and the voltage at D+ does not increase when revving the engine with the wire connected. I guess bad VR, YAY for the solution.
Today the battery had 12.6 volts at the battery terminals with the key on not running and the voltage going into the ignition switch was, 12.59V. Voltage coming out of the switch to the fuse box on wire #15 was only, 12.1 so, seems that the switch is the culprit for the V drop. I will see if cleaning it up will improve if not, replace it.
Thanks again,
M  |
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ashman40
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Joined: February 16, 2007
Posts: 16657
Location: North Florida, USA
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| Posted: Tue Aug 12, 2025 1:20 pm Post subject: Re: Crazy Electric Issue/Alternator |
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| Michaellatini wrote: |
Yesterday I checked the voltage at the D+ while the wire was still connected to the alt terminal. Today with it disconnected and the key on engine off, 11.27 volts from the fuse box.
With the 2W bulb connected directly from D+ to B+ the bulb stays lit when starting the engine and goes out when it is revved above 1600 or so and the voltage at D+ does not increase when revving the engine with the wire connected. I guess bad VR, YAY for the solution. |
Yeah, it seems like you have isolated it down to the VR inside the alternator. I hope you can still exchange it.
| Michaellatini wrote: |
| Today the battery had 12.6 volts at the battery terminals with the key on not running and the voltage going into the ignition switch was, 12.59V. Voltage coming out of the switch to the fuse box on wire #15 was only, 12.1 so, seems that the switch is the culprit for the V drop. I will see if cleaning it up will improve if not, replace it. |
Yeah, that is a pretty big voltage drop, but how is it you get a 12.1v reading on the black #15 wire coming from the ignition switch but your table indicates there is only 11.7v at the fuses? That is another 0.4v drop thru the fuse? If this is actually the case... clean the fuse contacts, on both ends of the fuse as well as both clips that hold the fuse. You could even clean up the male/female wire terminals on the trunk side of the fuse box.
If you have a spare 12v Bosch/Tycho style relay you could add the relay onto the black #15 wire coming off the ignition. Install it between the ignition switch and the fuse box. The weak voltage coming off the ignition switch will be connected to the 85/86 terminals of a SPST/SPDT relay. This controls when the relay is energized. This would control 12v coming off the red #30 wire coming from the rear seat area and when it would be passed to the ignition switched fuses (where the black #15 wire currently connects). This should increase the voltage that makes it to the ignition switched fuses and the GEN lamp. It also reduces the current flowing thru the ignition switch contacts so it can last much longer. The Bosch/Tycho style relays you can pick up from the FLAPS will usually operate with as little as 6.0v and 0.1A thru the 85/86 circuit.
_________________
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!} |
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Michaellatini
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| Posted: Tue Aug 12, 2025 2:16 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Yeah, it seems like you have isolated it down to the VR inside the alternator. I hope you can still exchange it.
Will not be able to exchange it since I bought it in December, 2022. I looked at the pics I took of the box when it arrived and it had been opened before and taped back. Didn't think much about it at the time. Called Summitt Racing to let them know since the issue has been there since first start up. They said, call Pertronix! No. I ordered another Bosch regulator from Topline today.
Yeah, that is a pretty big voltage drop, but how is it you get a 12.1v reading on the black #15 wire coming from the ignition switch but your table indicates there is only 11.7v at the fuses?
Sorry, to clarify, coming from the fuse box. I got that voltage at the spade disconnected from D+ to see the V drop to the engine bay. The V through the fuse was also, 12.1. 
12v Bosch/Tycho style relay you could add the relay onto the black #15 wire coming off the ignition.
I will check out this option, thanks again.
M |
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Michaellatini
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| Posted: Tue Aug 12, 2025 2:47 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Ashman, is this the idea for the relay? (inside the circle)
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ashman40
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Location: North Florida, USA
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| Posted: Wed Aug 13, 2025 9:23 am Post subject: Re: Crazy Electric Issue/Alternator |
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| Michaellatini wrote: |
Ashman, is this the idea for the relay? (inside the circle)
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Yes, but instead of splicing into the red wire coming off the headlight switch #30 terminal... add a terminal splitter to the headlight switch. Tap into the #30 terminal itself where the 6.0 wire coming from the VR connects to the switch. This will basically power the #1 & #2 fuses from the VR and not "steal" curret from one of the other circuits. This change alone should result in a measurable increase in the voltage available on the #15 fuses.
Check the voltage reading at the fuse box #2 where the small wire connects. This is the wire that powers the bottom 3 indicator lamps in the speedometer. Then test the voltage at the speedometer. Then test the voltage at the alternator D+. What level of voltage loss do you get? Clean the connections along this path and see if you can improve the voltage that makes it to the D+ on the alternator.
While I recognize that your alternator doesn't start charging until you rev the engine and this is "annoying". Your alternator appears to be producing enough charge to keep your electrical system running and also recharge the battery. Am I correct? That is the primary function of the charging system. If your alternator is capable of producing enough charge... are you just chasing the fix of the "annoyance"??
You mentioned sourcing a new VR from Topline. Is this a High Output VR? The stock alternator VR was rated at 50A/55A. Replacement VRs are usually stock replacements. I think you mentioned your Pertronix alternator is a 90A unit? Installing a stock VR into your Pertronix will likely downgrade it to a 55A alternator. Check the specs of your replacement VR.
I don't think you confirmed if your are running a belt driven AC compressor or are you running an newer electric (motor) AC compressor? I've been looking into the idea of runnning an electric compressor in my Beetle but the amp requirements all seem to be in the 70A range (they use a 70A or 80A fuse). That is nearly the entire capacity of a 90A alternator! This has made me question whether you could actually run an electric AC compressor on a Beetle?
_________________
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!} |
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Michaellatini
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| Posted: Wed Aug 13, 2025 12:24 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Thank you, Ashman!
I will do as you suggested with the wiring for the relay.
Once I get the alternator out and the new VR in I will follow up with you on the above advice.
Your alternator appears to be producing enough charge to keep your electrical system running and also recharge the battery. Am I correct?
Yes, you are correct. Last night the light came on while driving and stayed on bright and then this morning it was back to the usual.
Is this a High Output VR?
The add said it was for 90 amp or 55 amp. I hope it is for 90.
I have a belt driven A/C compressor. Sure would love the convenience of the electric but, I agree, lots of amps.
M |
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ashman40
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Location: North Florida, USA
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| Posted: Wed Aug 13, 2025 3:46 pm Post subject: Re: Crazy Electric Issue/Alternator |
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| Michaellatini wrote: |
| Last night the light came on while driving and stayed on bright and then this morning it was back to the usual. |
Ok, this really sounds like a bad VR. Earlier I was suggesting may be just "living with it" not charging at idle. But if it stops charging while you are driving... it is going bad.
| Michaellatini wrote: |
Is this a High Output VR?
The add said it was for 90 amp or 55 amp. I hope it is for 90. |
Hmmm, well I don't know of a consistent way to test the output amperage of your alternator. But as long as you get enough current so you get a 13.8v reading at the battery terminals with everything ON you are good.
| Michaellatini wrote: |
| I have a belt driven A/C compressor. Sure would love the convenience of the electric but, I agree, lots of amps. |
I'm looking for a way to install a 200A GM truck alternator on a bracket and drive it using a longer v-belt or possibly a serpentine belt. This would solve any power needs a Beetle could have. 
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AshMan40
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'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!} |
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Michaellatini
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Joined: August 08, 2004
Posts: 227
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| Posted: Thu Aug 14, 2025 8:18 am Post subject: Re: Crazy Electric Issue/Alternator |
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Thanks again, Ashman.
200 AMPS?!?! Wow. I have seen the conversion in several pictures and addition too. Guessing the addition original alternator might be gutted. No clue.
Good luck with the AC project. I tied 2 of the vents into the rear air feed under the back seat so I have dry air to the windshield in the rain, hot or cold outside. Works great. Put the air unit behind the back seat and have a cutout switch on the compressor for the winter. When you turn on the fan and open the heater boxes it get hot in the car quick and great for around town driving. If it's too moist inside, flip the compressor switch on and heated dry air!
M |
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vamram 
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Joined: March 08, 2012
Posts: 8066
Location: NOVA
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| Posted: Thu Aug 14, 2025 8:35 am Post subject: Re: Crazy Electric Issue/Alternator |
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| ashman40 wrote: |
I'm looking for a way to install a 200A GM truck alternator on a bracket and drive it using a longer v-belt or possibly a serpentine belt. This would solve any power needs a Beetle could have. |
Just a side note - Ashman, I hope you document this in a separate thread!
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talljordan
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Joined: January 10, 2012
Posts: 1127
Location: San Francisco, CA
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| Posted: Thu Aug 14, 2025 9:57 am Post subject: Re: Crazy Electric Issue/Alternator |
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CIP sells a 90A drop in alternator, which is more than enough for any needs you could possibly have.
If you do the 200A, I hope you upgrade all the wires in your car as well, you don't want those melting. You'll also need to retune your carb, 200A is more than 3HP, so it could stall out your engine.
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Michaellatini
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Joined: August 08, 2004
Posts: 227
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| Posted: Mon Aug 18, 2025 1:17 pm Post subject: Re: Crazy Electric Issue/Alternator |
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Took the alternator to a reputable repair shop here in MD. They tested it and said, it's garbage, take it back to the people that stole your money!
It was rebuilt by, Pertronix and sold by Summit Racing. Neither company wants to take any responsibility.
I only say this because what is wrong with it was there from day 1. I am done with both companies and suggest you stay away from them also.
Michael |
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