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EVfun
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PostPosted: Tue May 11, 2021 4:35 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Dan2973 wrote:
Hey guys I have been trying to figure out what is draining my battery down and I’m stumped. I have a 1966 beetle I restored. It’s 6 volt and everything is clean and new including wire harness and fuse block and optima battery. I ruled out the retro radio because I disconnected it and my battery still drains down to 6.2v. I have been reading similar posts and reading the Bentley and other manuals. I have ruled out a parasitic drain by testing with a test light at the battery and also with a voltage meter. I have documented voltage each day for a week after a full charge. I start with like 7 v the first day and falls to 6.5 v by day 5. So today I take the car to my moms and on the way home it rains so I turn on the lights and wipers and make it home to my house and shut the car off in the driveway. Go to start it right after and it’s dead at 6.2v. Now I have ran tests such as testing the battery at 2000 rpm with a voltage meter and the voltage spikes up. I also tested the generator output with a voltage meter by grounding out DF and hooking up the meter to the D+ and rev up to 2000 rpm and the voltage spikes to like 20. Could it be the regulator? I’m not understanding the Bentley when it talks about connecting sliding resistance with an ammeter. Can anyone simplify the regulator test? Any other help would be appreciated. Thanks guys

Running voltage regulator and drive-train ground test needed...

Measure the battery voltage at the battery and at the voltage regulator before starting the car. They should be the same. 6.0 volts is about 20% state of charge and the car may not start. 6.2 volts is about 60% state of charge. 6.4 volts is about 100% state of charge.

Start the car and let it run for a couple minutes with no accessories on. Ideally this is at a fast cold idle because generators don't charge well at idle. Now prop the carb back up to a fast idle and measure the voltage at the regulator and at the battery. It should be the same at both points and between 6.6 and 7.0 volts. If it is 6.5 let it run a bit longer and check again. Functional charging requires the voltage be at least 6.6 volts.

If it is less than the first tests before starting the car you are not charging at all. If it is between 7.0 and 7.4 volts you're charging a bit hot, but this only slightly shortens battery life (watch for battery acid leaking at elevated voltages -- old sheet metal IS valuable.) Lead acid batteries fail much quicker from undercharging or running dead than from overcharging -- even sealed batteries like Optimas unless you run it up over 7.5 volts and leave it at that level for hours.

If the voltage is different by more than a few hundredths of a volt between the voltage regulator and battery in the running test then you have issues keeping the battery from getting the charge the generator is offering. It could be ground or power side, further tests required.

NOTE: updated SOC voltage numbers for starting type batteries. They run a bit lower voltage at any SOC than deep cycle lead acid batteries.
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Eric&Barb
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PostPosted: Tue May 11, 2021 8:38 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Dan2973 wrote:

I drive the car a few times a week. Why do you think it doesn’t start at 6.3 v?


You might need to reread our second post on this thread.

Wiring connections and grounds must be clean and tight.....

Do post image of the battery cable clamp ends.
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PostPosted: Wed May 12, 2021 5:00 am    Post subject: Re: Another voltage regulator ? Reply with quote

Eric&Barb wrote:
Dan2973 wrote:

I drive the car a few times a week. Why do you think it doesn’t start at 6.3 v?


You might need to reread our second post on this thread.

Wiring connections and grounds must be clean and tight.....

Do post image of the battery cable clamp ends.


Thanks. I’m going to put the battery back in the car. Take photos and check voltage of regulator and battery. I will document everything and report back. I will also recheck ground straps
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PostPosted: Wed May 12, 2021 11:39 am    Post subject: Re: Another voltage regulator ? Reply with quote

Dan2973 wrote:
I will also recheck ground straps


...both battery and tranny straps, remember.
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PostPosted: Wed May 12, 2021 4:14 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Eric&Barb wrote:
Dan2973 wrote:

I drive the car a few times a week. Why do you think it doesn’t start at 6.3 v?


You might need to reread our second post on this thread.

Wiring connections and grounds must be clean and tight.....

Do post image of the battery cable clamp ends.


Ok so I got home from work and jacked up the rear of the bug and slid underneath to check on the tranny ground strap. To my surprise I couldn’t believe that it was loose as a goose. So loose that it was flopping around. I must of forgot to tighten it during the restoration at some point. So I Started to clean all the metal with a cookie disc and noticed that the aftermarket trans mount was coated with s rubber skin all over the trans mount and especially where the strap grounds. I cleaned everything up and added a lock washer. I’m thinking maybe this was the problem all along? How will I know for sure?
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PostPosted: Wed May 12, 2021 4:24 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Definitely was not helping to have that ground loose!!!

Do put on your future parts list to get the Wolfsburg West battery cables that are made just as the factory ones with brass clamps that are soldered onto the battery cables. Soldering means no way for battery acid to seep in between the clamp and cable They are much better and longer lasting if you do not over tighten them onto the battery terminals. So they cost less $$ over time.

Well if the VW starts after sitting for days and/or with the battery voltage about 6 volts, then that was the problem. Still you could have fixed one problem and have a few more to tackle.....
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PostPosted: Wed May 12, 2021 4:28 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Side issue, but I would not recommend carpet or anything that can soak up battery or other leaks and encourage/hide rust. Maybe a sheet of rubber, but no sponges!
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PostPosted: Wed May 12, 2021 4:31 pm    Post subject: Re: Another voltage regulator ? Reply with quote

KTPhil wrote:
Side issue, but I would not recommend carpet or anything that can soak up battery or other leaks and encourage/hide rust. Maybe a sheet of rubber, but no sponges!


Good point! A battery box that fits in there, even if you have to cut it down to 1" (25mm) tall walls would be much better to catch the battery acid.
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PostPosted: Thu May 13, 2021 2:55 am    Post subject: Re: Another voltage regulator ? Reply with quote

Eric&Barb wrote:
Definitely was not helping to have that ground loose!!!

Do put on your future parts list to get the Wolfsburg West battery cables that are made just as the factory ones with brass clamps that are soldered onto the battery cables. Soldering means no way for battery acid to seep in between the clamp and cable They are much better and longer lasting if you do not over tighten them onto the battery terminals. So they cost less $$ over time.

Well if the VW starts after sitting for days and/or with the battery voltage about 6 volts, then that was the problem. Still you could have fixed one problem and have a few more to tackle.....


Thanks. Im going to get those cables ordered. I believe I tried to order those from WW originally but they were out of stock. Is that normally the way to have to take off the rubber coating off of the mount? Thank you
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PostPosted: Thu May 13, 2021 8:08 am    Post subject: Re: Another voltage regulator ? Reply with quote

Dan2973 wrote:
Is that normally the way to have to take off the rubber coating off of the mount? Thank you


Not that we have seen. Problem is the quality of parts all too often has gone downhill. Which is why so many would rather install a used part instead of new repro.
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PostPosted: Fri May 14, 2021 12:34 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Eric&Barb wrote:
Dan2973 wrote:
Is that normally the way to have to take off the rubber coating off of the mount? Thank you


Not that we have seen. Problem is the quality of parts all too often has gone downhill. Which is why so many would rather install a used part instead of new repro.


I thought I had this licked. I found the ground strap on the tranny and fix that. Then I ran tests at the battery and regulator at idle and got 6.6 V at each. Then I started it up and revved it up and tested each again and got 7.2 V . Woke up this morning and tested the battery and I was at 6.6 V. So I decided to take the car out to run some errands today for like 10 miles. On the way back home down the street from my house I noticed the car had a really low idle. I pulled into my driveway and let the car idle for a few minutes and all of a sudden it just shut off on its own totally dead. I had nothing. I thought I blew a fuse but I didn’t. I tested the battery and I had 3 V. I jumped it with a jumper Pack and it started. With the tester on it I noticed that the volts were dropping drastically at idle. So I pull the car into the garage take the battery out and tested and it’s at 6.37 V. So now I have a NAPA acid battery in it that is showing 6.37 V. This car won’t star unless I have over 6.37v. Please help meeeeeeeeeeeeee ugh
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PostPosted: Fri May 14, 2021 2:04 pm    Post subject: Re: Another voltage regulator ? Reply with quote

OK so just an update. I took the red top optima battery to my FLAP and they tested it and said it’s shot. When they put a load on it it falls to 2v. Now the question is I could order another battery but how do I know this isn’t going to happen again? What is causing to kill the battery?
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PostPosted: Fri May 14, 2021 2:04 pm    Post subject: Re: Another voltage regulator ? Reply with quote

You should be able to start with 5V if your starter and state of tune are decent.

I suspect a combo of bad regulator and worn/dirty starter solenoid.
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PostPosted: Fri May 14, 2021 3:36 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Starting batteries die fastest from deep cycling and from spending to much time at a low state of charge. Overcharging can kill them but takes longer. They die in 5 to 10 years even when treated well. Charging and discharging slowly damage the plates.

I would measure the voltage of your new battery before installing it. Then install the battery and start the car. Right after starting, with the fast cold idle still on and no accessories on, measure the voltage between the regulator output and the engine case. Now run around quickly and measure the voltage between the battery posts. Both should be within a few hundredths of a volt of each other and higher than your reading of the battery before installing.
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PostPosted: Fri May 14, 2021 3:45 pm    Post subject: Re: Another voltage regulator ? Reply with quote

EVfun wrote:
Starting batteries die fastest from deep cycling and from spending to much time at a low state of charge. Overcharging can kill them but takes longer. They die in 5 to 10 years even when treated well. Charging and discharging slowly damage the plates.

I would measure the voltage of your new battery before installing it. Then install the battery and start the car. Right after starting, with the fast cold idle still on and no accessories on, measure the voltage between the regulator output and the engine case. Now run around quickly and measure the voltage between the battery posts. Both should be within a few hundredths of a volt of each other and higher than your reading of the battery before installing.


I guess I’m ordering another optima 6v. 200 bucks. I’m just wondering could the very loose trans ground strap have caused this all along? I was always having to charge the battery with a jump pack and trickle charge
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PostPosted: Fri May 14, 2021 3:47 pm    Post subject: Re: Another voltage regulator ? Reply with quote

A proper load-based battery tester will tell you if your battery is good.
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https://www.amazon.com/OEMTOOLS-24338-100A-Battery...&psc=1

These add up to 100A load.

I simulate this by turning on all lights, radio, wipers, and measuring battery voltage before and during cranking. I probably don't even break 50A but it at least puts a hard load on it, and it's free.
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PostPosted: Fri May 14, 2021 4:12 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Dan2973 wrote:
OK so just an update. I took the red top optima battery to my FLAP and they tested it and said it’s shot. When they put a load on it it falls to 2v. Now the question is I could order another battery but how do I know this isn’t going to happen again? What is causing to kill the battery?


If you do not daily drive this VW say during Winter due to road salt, you need a battery minder to keep it in tip top shape. We have easily gotten 8 to 10 years out of a battery due to daily driving it year around. Now that we are not DD both the type 2s so much, have gotten a Black and Decker battery minder to keep them up.

Of course not having a good ground at the transaxle did not help. Lead acid batteries do not do well getting drawn down too much in voltage. If memory serves correctly going below 10.5 volts for a 12 volt system will pretty quickly damage the battery. So that should be about 5.25 volts for a 6 volt battery.....

Again, going thru all the electrical connections and grounds is a must. A voltage meter can show you changes in the wiring from the battery voltage when that circuit is turned on.
EG with headlights turned on, what is the battery voltage and what is the voltage getting to the headlights??? Same can be done with the grounds to see if there is voltage resistance between grounding surfaces.
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PostPosted: Fri May 14, 2021 4:31 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Dan2973 wrote:
EVfun wrote:
Starting batteries die fastest from deep cycling and from spending to much time at a low state of charge. Overcharging can kill them but takes longer. They die in 5 to 10 years even when treated well. Charging and discharging slowly damage the plates.

I would measure the voltage of your new battery before installing it. Then install the battery and start the car. Right after starting, with the fast cold idle still on and no accessories on, measure the voltage between the regulator output and the engine case. Now run around quickly and measure the voltage between the battery posts. Both should be within a few hundredths of a volt of each other and higher than your reading of the battery before installing.


I guess I’m ordering another optima 6v. 200 bucks. I’m just wondering could the very loose trans ground strap have caused this all along? I was always having to charge the battery with a jump pack and trickle charge

Yes, it can cause this because the battery may have been trying to live at a low state of charge. "SLI" (Starting Lighting Ignition) batteries cannot handle that well, the plates fall apart much faster than in a good life. The bad connection means you needed to charge the battery to a high level to start the car, because it caused a voltage drop between the battery and starter when cranking. It also caused a voltage loss between the generator and battery that hurt charging. The poor battery may have been mostly near dead, except when you manually charged it.
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PostPosted: Sat May 15, 2021 3:46 am    Post subject: Re: Another voltage regulator ? Reply with quote

EVfun wrote:
Dan2973 wrote:
EVfun wrote:
Starting batteries die fastest from deep cycling and from spending to much time at a low state of charge. Overcharging can kill them but takes longer. They die in 5 to 10 years even when treated well. Charging and discharging slowly damage the plates.

I would measure the voltage of your new battery before installing it. Then install the battery and start the car. Right after starting, with the fast cold idle still on and no accessories on, measure the voltage between the regulator output and the engine case. Now run around quickly and measure the voltage between the battery posts. Both should be within a few hundredths of a volt of each other and higher than your reading of the battery before installing.


I guess I’m ordering another optima 6v. 200 bucks. I’m just wondering could the very loose trans ground strap have caused this all along? I was always having to charge the battery with a jump pack and trickle charge

Yes, it can cause this because the battery may have been trying to live at a low state of charge. "SLI" (Starting Lighting Ignition) batteries cannot handle that well, the plates fall apart much faster than in a good life. The bad connection means you needed to charge the battery to a high level to start the car, because it caused a voltage drop between the battery and starter when cranking. It also caused a voltage loss between the generator and battery that hurt charging. The poor battery may have been mostly near dead, except when you manually charged it.


Thanks. Just ordered a new optima and the battery load tester you showed me. And just to clarify... the car wouldn’t start at 6.2v with the bad battery because once I turn the key with the load the battery drains to 3 v and cannot turn the starter? Is that correct?
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PostPosted: Sat May 15, 2021 1:08 pm    Post subject: Re: Another voltage regulator ? Reply with quote

Dan2973 wrote:
EVfun wrote:
Dan2973 wrote:
EVfun wrote:
Starting batteries die fastest from deep cycling and from spending to much time at a low state of charge. Overcharging can kill them but takes longer. They die in 5 to 10 years even when treated well. Charging and discharging slowly damage the plates.

I would measure the voltage of your new battery before installing it. Then install the battery and start the car. Right after starting, with the fast cold idle still on and no accessories on, measure the voltage between the regulator output and the engine case. Now run around quickly and measure the voltage between the battery posts. Both should be within a few hundredths of a volt of each other and higher than your reading of the battery before installing.


I guess I’m ordering another optima 6v. 200 bucks. I’m just wondering could the very loose trans ground strap have caused this all along? I was always having to charge the battery with a jump pack and trickle charge

Yes, it can cause this because the battery may have been trying to live at a low state of charge. "SLI" (Starting Lighting Ignition) batteries cannot handle that well, the plates fall apart much faster than in a good life. The bad connection means you needed to charge the battery to a high level to start the car, because it caused a voltage drop between the battery and starter when cranking. It also caused a voltage loss between the generator and battery that hurt charging. The poor battery may have been mostly near dead, except when you manually charged it.


Thanks. Just ordered a new optima and the battery load tester you showed me. And just to clarify... the car wouldn’t start at 6.2v with the bad battery because once I turn the key with the load the battery drains to 3 v and cannot turn the starter? Is that correct?

If you are measuring at the battery posts that would be the end of life expectation. It could hold a surface charge, but most of the active plate material had become detached from the plates so it had almost no actual storage capacity.

The bad connection issue would cause the voltage at the battery to be higher, sometimes a lot higher, that what would be measured at the starter when cranking. It would mean that once the car was running the voltage at the regulator would be higher than at the battery.

When you get the new battery in it is important to verify the connections and then do a running test to make sure you are charging the battery. 7 volts on the running engine would be great but if that was still only 6.4 volts at the battery you would have a bad connection to find so the new battery doesn't get killed. Most batteries don't die of old age, they're murdered!

It did get one to die of old age. I put a battery in my '65 Dart back in 1994 and drove the car until 2003 with that battery. When new I bet I could have left the headlights on for 8 hours with the car off and still started the engine. At the end of life the positive post was loose in the case and if you left the headlights on for 15 minutes it was not going to start the engine, little active plate material left. It was fall and I was pretty sure that battery would leave me walking home in a cold rain if I tried to push another winter out of it. I also had to replace the positive battery cable due to corrosion from the loose post. I replaced it with an Optima. That car had the mechanical voltage regulator adjusted so the peak voltage occasionally hit, but never exceeded, 14.8 volts.
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