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Wed Jul 20, 2011 4:23 pm

How much amps will a 6 volt generator put out? (The car is a 1961 Beetle)

Wed Jul 20, 2011 4:41 pm

Look at your generator.

Example

(ignore the arrow, that's the date stamp)

See the 160? The 160 = 160 watts.

Amps = Watts/Volts

This is a 6-volt generator (note the 6 after the 160)

So 160/6 = 26.6 amps

Wed Jul 20, 2011 5:43 pm

In 1961 they were using a 180 Watt generator.

That 180 watts (or 160W if that's what you have) is a "nomimal" rating. Maximum output is higher than that. Especially when you consider the voltage regulator is 7VDC. 6V generators built later on would say 7V on them. (just like 12V generators say 14V)

Now, those specs were still the rating they were using in 1965. I have a 1968 Bosch catalog that shows the 1965 generator as being the Bosch new-number 0 101 212 006, and that that was the replacement unit for older 6V cars. That generator was rated at 7V - 45amps. here's a small snip from a photo I found in the classifieds:

-Andy

Thu Jul 21, 2011 12:14 am

Looking my 1960 shop manual, I read it as the 180 watt generator is considered to be 45 amps.

Some of the earlier manuals read like the 180-watt max. may be 25 or 30 amp though as they talk about testing with a 25-amp bulb and 30-amp gauge where as the 45-amp version is tested with a 50-amp gauge. It's the same for the 160-watt generator - 25/30.

Maybe an improvement was made at some point?

I don't see anything in Progressive Refinements beside the change from 160-watt to 180-watt to 200-watt

Mon Oct 04, 2021 11:46 pm

How many watts is this one rated for?

I would love to find a table of specs. on these old generators. At https://www.thesamba.com/vw/forum/viewtopic.php?p=7419461#7419461 there is an EARLY BOSCH GENERATOR REGULATOR CHART, and I think there was a tight relationship between regulators and generators. But the chart is describing something like Load Setting Watts, which might just be a test condition, not a spec.

Do the 7V 45A stampings mean that you can run continuously at 7 x 45 = 315 watts? Or maybe 6 x 45 = 270 watts? The Setting Watts in the chart are only 160 or 180.

Tue Oct 05, 2021 3:46 am

These ratings, if real, were valid when generators were new.

Rust weaks the copper windings and the collector, don't expect to use the nominal power Bosch promises.

Those value are only to help choosing the correct regulator.

Tue Oct 05, 2021 8:37 am

Rust never sleeps!

I agree, so what would be some reasonable parameters for a typical "rebuilt" generator (e.g., 6 VOLT GENERATOR, REBUILT)?

I don't think the generator itself really cares about the voltage, as such, since the open circuit tests can go up to 25v or something.

I think you said that your 30A fuse on D+ has never blown, so it seems like the 45A is wishful thinking and would not happen in normal operation.

It look like the Two Unit TA Regulator Curve at https://www.thesamba.com/vw/forum/viewtopic.php?p=9251212#9251212 is intended to limit the power to 200 watts or so. But, that limit might be different for a different generator/regulator. I'm thinking that the power is one of the most important things the regulator needs to regulate, but it's hard to put a number on it.

Hmmm. Maybe the ideal solution would be a thermocouple on (or in?) the generator and a regulator that optimizes charging while limiting the generator temperature. (Again, hard to put a number on what the limit should be.)

Tue Oct 05, 2021 11:11 am

In part of the old Bosch part number was the nominal voltage, setting/ testing load in Watt at a given RPM (or rated power). For example a 180/6/2500 generator should be able to deliver 180W at 2500rpm when tested and healthy.

When Bosch changed to the 10-digit part number they instead also stamped them with the regulated voltage and highest allowed charging current, for example 7V 45A.

When testing the generator and you needed the rated power with the new part number/ markings you took the marked current and multiplied it with x4, for example
45A x 4 = 180W

So an old "180W" and a newer "45A" has the same rated power. 40A and 160W as well.

For 12V you multiplied with x8 to get the rated power

Tue Oct 05, 2021 11:20 am

Frederik wrote: In part of the old Bosch part number was the setting/ testing load in Watt at a given RPM (or rated power). For example a 180/6/2500 generator should be able to deliver 180W at 2500rpm when tested and healthy.

When Bosch changed to the 10-digit part number they instead also stamped them with the regulated voltage and highest allowed charging current, for example 7V 45A.

When testing the generator and you needed the rated power with the new part number/ markings you took the marked current and multiplied it with x4, for example
45A x 4 = 180W

So an old "180W" and a newer "45A" has the same rated power. 40A and 160W as well.

For 12V you multiplied with x8 to get the rated power

Excellent! That's the info. I was looking for. Thanks.

One question: is that 2500rpm on the generator shaft or the engine crankshaft?

Sun Jan 09, 2022 8:43 pm

So, how about output voltage ?

I think my generator is an original '66 except for brushes:

It only has around 1 volt on D+ at idle.

I also have a "rebuilt" generator that I bought from JBugs in 2019:

It hasn't been on the car in a couple of years, but, as I recall, it was about the same.

In either case, the red light in the speedometer is always on at idle.

Is this normal, or is something wrong with both of these units?

I'd like to run LED headlights, but I'm only getting volts in the low 4s at the headlight terminals on high beams with the sealed beam incandescents installed. Looking at these: VC6v – 7 INCH LED HEADLIGHT KIT, I read "It will also operate all the way down to 6.5V at 80% brightness. Please note that most 6V vehicles will normally generate 7.5V at idle with a healthy wiring system.", which makes me think my system is not healthy.

Sun Jan 09, 2022 8:58 pm

carlk3 wrote: In either case, the red light in the speedometer is always on at idle. Is this normal, or is something wrong with both of these units?
Red charging light on at idle is not atypical. If your generator does its job, and your VW starts like it should (assuming a good battery), then everything is OK, don't worry about it.

If your idle is low, raise it a little, that might help.

Mon Jan 10, 2022 9:21 am

I would check the entire path (including grounds) for your headlights to get the voltage drop down to a half volt or less.

Mon Jan 10, 2022 11:05 am

How much drop is expected along the big red #30 wire running from the starter to the headlight switch? If I knew the gauge, or mm2, and the length, and the current, I could estimate a theoretical drop. I could measure the current, but I don't want to strip off insulation just to measure the size of the wire, and it's hard to measure the length with the wiring in the car.

Currently*, I'm seeing a drop of around 0.6v from battery terminal to headlight switch terminal on high beams (incandescent sealed beams).

* No pun intended

Mon Jan 10, 2022 11:44 am

carlk3 wrote: How much drop is expected along the big red #30 wire running from the starter to the headlight switch? If I knew the gauge, or mm2, and the length, and the current, I could estimate a theoretical drop.

Size of each wire is listed in all of the stock VW manual wiring diagrams. At the bottom of the list of wiring diagrams there is a Wiring Conversion Chart and a few other pieces of need to know info folks seem never to get down to and read.

With our bigger buses with longer wiring have easily gotten voltage drops down to no more than 1/10 of a volt between battery and places like headlights and even right on back to the taillights.

Soldering each internal connection inside the fuse box really helps with voltage drops. If you have early bell shaped headlight switch solder internal/external connections in/on it.

http://www.thesamba.com/vw/forum/viewtopic.php?t=483901&highlight=fuse+box+soldering

http://www.type2.com/library/electris/vw-hauptlicht-schalter.html

Replace any cheap aftermarket wiring terminals with factory style brass ones.

Crimping tool.

http://www.thesamba.com/vw/forum/viewtopic.php?t=338938&highlight=uninsulated+crimper
_________________

Mon Jan 10, 2022 11:48 am

There should be no measurable drop from the regulator terminal to the headlight switch. It should be a single, thick (6mm) wire. Resistance over 10 feet would be about 10 milliohms.

If you have a drop there, there may be faulty terminals, aa parasitic draw from the rest of the circuit, or a bad ground at the regulator itself.

There are many other wires and terminals form that point down to the bulbs themselves, but this segment should be almost perfect.

Mon Jan 10, 2022 5:52 pm

KTPhil wrote: There should be no measurable drop from the regulator terminal to the headlight switch. It should be a single, thick (6mm) wire. Resistance over 10 feet would be about 10 milliohms.
...
Thanks! If it's 10 milliohms, and the high beams + running lights draw roughly 20 amps, wouldn't I see a drop of about 0.2v?

I'm making preparations to do a third, really thorough this time, probing session.

Mon Jan 10, 2022 6:18 pm

Eric&Barb wrote:
...
Size of each wire is listed in all of the stock VW manual wiring diagrams. At the bottom of the list of wiring diagrams there is a Wiring Conversion Chart and a few other pieces of need to know info folks seem never to get down to and read.

I can't find it in the Bentley*. Maybe I need to poke around some in the Technical section here (https://www.thesamba.com/vw/archives/info/wiringt2.php).

Eric&Barb wrote:
With our bigger buses with longer wiring have easily gotten voltage drops down to no more than 1/10 of a volt between battery and places like headlights and even right on back to the taillights.

Soldering each internal connection inside the fuse box really helps with voltage drops. If you have early bell shaped headlight switch solder internal/external connections in/on it.

http://www.thesamba.com/vw/forum/viewtopic.php?t=483901&highlight=fuse+box+soldering

http://www.type2.com/library/electris/vw-hauptlicht-schalter.html

Soldering the fuse block was one of the first things I did (and I thank you for your advice and instructions on that!). My intent was to do some probing to find the voltage drop, and as soon as I put my VOM test lead on a tab on the fuse block I could immediately hear my headlight alarm change pitch, so I knew right away I had a problem there. So soldering that was a major improvement.

However, I'm still only getting volts in the low 4s on the headlight terminals. So, then I overhauled and soldered the headlight switch. It looked pretty rough inside, but, surprisingly, I did not see a huge difference.

Eric&Barb wrote:
Replace any cheap aftermarket wiring terminals with factory style brass ones.

Crimping tool.

http://www.thesamba.com/vw/forum/viewtopic.php?t=338938&highlight=uninsulated+crimper
_________________
I put in a new WK-143-6165 wiring harness "only" 15 years ago, or so. And I did get myself a Del City crimp tool and a bunch of connectors from Digi-Key (as recommended in these forums) so I can make proper repairs.

At this point, I have eliminated a lot of possibilities by trial and error. The place I'm thinking of focusing on next is the connections on starter terminal 30. Maybe there is a bad crimp connector on the big red wire, or something. I used to have a lot of problems with the starter (since sorted out), so I think the connections are in good shape, but maybe I didn't look too closely at the crimp connections. There is a kind of stack of ring connectors on there because of a hard start relay installed by a previous owner sometime prior to 1982.

* [EDIT] OK, now I see that each line in the diagram in the Bentley has little annotation like "6,0" next to it, which must mean "6.0 square millimetres."

Tue Jan 11, 2022 11:01 pm

I did a third probing session, from end to end, and then a fourth after some repairs:
https://docs.google.com/spreadsheets/d/e/2PACX-1vS...Z/pubhtml#

I wrote up the results here:
https://www.thesamba.com/vw/forum/viewtopic.php?p=9785057#9785057

I think the main culprit was a bad crimp connection on the big red #30 wire at the starter solenoid end.

The net drop now is 1.0v from a battery at 5.8v to the high beam terminal of the passenger side headlight (about 17%). The biggest drop in the path is 0.38v from the starter #30 to the headlight #30. The second biggest is 0.27v from the fuse block to the headlight terminal. I get 4.8v between the ground and high beam headlight terminals (from a battery at 5.8v).

Wed Jan 12, 2022 1:18 pm

A few things come to mind:

1. What wattage of headlight bulbs are you using?

2. Double check the headlight bulb connector wiring. Have a 1961 beetle in the family since at least the early 1970s that always had terrible dim headlights. After I inherited it, found that one of the headlight sockets had been miswired. Probably that fender needed to be removed and the person slipped out the terminals from socket due to the socket will not fit thru the fender hole for the wiring. That resulted in all four bulb filaments running all the time, even if the dimmer floor switch was operated. Which the original wiring could not keep up with the draw for all of those bulb filaments heated up.

3. Really doubt it, but remote possibility that the cables from battery to the headlights could perhaps be undersized. All it would take is for someone at the manufacture of that cable to mislabel some spools of wire....
Bought a set of engine bearings for my second rebuild about 1990 and turned out they were a size too big for the crankshaft. Bearings were vacuum packed with plastic over thick cardboard backer with printed size on the cardboard. Plus they made by a reputable German manufacture that supplied VW with bearings back in the 1960s!

Wed Jan 12, 2022 2:18 pm

Are you saying you have a wire from the starter to the headlight switch?
That is not normal. The supply wire should be from the regulator to the headlight switch.