6v generator/regulator

[sknappy]

I was wondering what the voltage output should be at the battery when the headlight is on and when it is not. I am running about 6.5 to 6.7 volts, doesn't change if the headlight is on or off. Seems to me this should be a little higher than that, maybe not.

[bmh]

You should be checking amps, not volts to determine if your regulator is working properly. The service manual for your year and application should give instructions on testing.

[RvP]

Purpose of the voltage regulator

The purpose of the voltage regulator is to keep the generator voltage constant (approx. 7.2V) regardless of the current draw. Therefore the voltage should be the same with headlights on or off (plus or minus a few tenths of a volt). That’s the beauty of a regulated generator versus a 3 brush.

A 3 brush generator does not have a way of producing a steady voltage output and the voltage is dependent on battery condition, electrical load and RPM. When setting up a 3 brush you need to adjust it using an ammeter to set the proper current output based on all the variables. Set it up incorrectly and you will either have insufficient current output to keep the battery charged or too much current and boil the electrolyte out of the battery and burn out electrical devices such as lights.

With a 2 brush and a voltage regulator you only need to check that the voltage is steady across the RPM range and the electrical load with a voltmeter. If the voltage dips significantly then a few probable causes are:

1) The generator is weak and cannot put out enough for the demand.
2) The electrical load has exceeded the capabilities of the generator such as too many lights, weak battery sucking a lot of current, electrical short., etc.

Harley made 2 types of mechanical voltage regulators, “2 unit” and “3 unit”. Both have a cut out relay to prevent the battery from discharging into the generator when the generator output is less than the battery at low engine RPMS.

Both have a 2nd relay that controls the generator voltage to keep the voltage steady across the RPM range and electrical load.

The “3 unit” has a 3rd relay that protects the generator from putting out more current than the armature can safely handle. For example if the generator’s limit is 13 amps the 3rd relay will cut back the generator’s output if more than 13 amps is required from the generator.

The “2 unit” was typically used on 6V 2 brush generators with the standard lighting load and some accessory lights.

The “3 unit” was typically used when a radio was employed on the motorcycle due to the high current demand of the radio on the electrical system and the battery.

[RvP]

More thoughts

Just 2 more thoughts…….

Another cause of low voltage with a 2 brush system can be the voltage regulator out of adjustment or a faulty regulator.

I also just want to make sure you are not fighting a losing battle with regards to the headlight you are using. On 1949 and up panheads the only readily available 6V sealed beam headlight on the market is not designed for a low output generator such as a 3 brush 32E or 52. As far as I know the only available 6V sealed beam is a 6006 and it draws more current than a 3 brush generator (32E or 52) can put out.

On a good day the 3 brush 32E can handle a 10 amp load maximum and less when properly setup. When properly setup it is adjusted for 4 amps without the lights on and will be boosted to 7 1/2 amps when the lights are on. This means that the total stock lighting load is expected to be around 3 ½ amps.

The stock T3 headlight fit these parameters pretty well. The 6006 headlight available today by itself draws 6.45 amps on low beam and 8.06 amps on high beam, way outside the design parameters of the 3 brush generator.

A 2 brush generator with a voltage regulator may be able to keep up with that current demand or just break even neither charging or discharging. If you search the auction websites you will find when a T3 headlight comes up for sale it is usually way over $100 (yes, that’s one hundred dollars).

Just figured I would also pass this along.

[Rooster]

RvP, that's excellent information. I've copied and saved it to my files for reference. Thanks for exlaining it in simple English.

[ManPan]

Thanks RvP !!! I've been fighting this issue for over a year..Guess I'd better buck up and find a T3 if I want to ride the '50 in the twilight...

[RvP]

Some Failed Solutions and a promising one

I don’t have a panhead, just a 45 but a good friend of mine does and that’s how I became familiar with the problem of using the 6006 headlight with a 3 brush generator. You can read some of my findings in the forum archives that he posted, panhead section, #153, “panhead sealed beam headlight”.

Since that thread I built a modulator for the 6006 to get the current consumption down. The modulator ran at about 100Hz and a 40/60 duty cycle. This gave an average current draw equal to the stock low amp headlight. The light was very bright but just not concentrated enough. The problem appears to be the focal arrangement of the 6006.

A motorcycle headlight (from my experience) puts out a round beam of light concentrated in front. A car headlight puts out a wide but thinner band of light. My opinion is that the 6006 is designed for car use more than a motorcycle. The 6006 throws lots of light in that wide/thin array as a car headlight. With the current reduced using the modulator the amount of light concentrated in front of the motorcycle isn’t that much since it is spread wide to the left and right. This looked great in the backyard but proved not bright enough to safely drive with.

I also tried putting a springer bulb (#2320) in a 7” headlight shell made by CIBIE for converting 7” sealed beams to halogen. This produced what we call the “porch light” effect which does not light up the road at all past 5 feet. Bottom line is the focal length just isn't correct for the springer bulb.

Since then I added spot lights to my lowly 45 to make my panhead friend even more jealous of my superior lighting. I ran into the same problem with the 32E 3 brush, especially since I drive in the daytime with the high beam on and at speeds averaging 50mph. The 3 brush just didn’t keep the battery peaked enough to have sufficient reserve for the spot lights when I would use them at night for some duration.

One solution that I am testing now for my 45 with spot lights that will apply to his panhead is an extremely simple conversion for the 32E 3 brush to 2 brush, not for the purist or 12V advocates. What makes the conversion so simple is that I did not move any existing wires on my 45 or inside the generator. Every wire is exactly where Harley put it and on the panhead, this can be done without even removing the generator. The neat part is that to put it back to 3 brush operation only requires putting the 3rd brush back in and removing the hidden voltage regulator.

I have been “stress testing” my 32E with this arrangement and the difference between 3 brush and this simple 2 brush conversion is literally like night and day. My current draw on the 45 is a little more with the spot lights than it would be on the panhead with the 6006 headlight.

Unfortunately my friend’s panhead is down right now with an ignition problem and when it’s back up we will try this setup on his 32E using the 6006 headlight. In the meantime I promised him I would stress my 32E and I have been faithful to my promise lighting up the south ‘jersey pinelands as much as I can for the last month.

Since I only have a sample of 1 with this easy conversion I am hesitant to recommend it since it can harm the generator, battery, electrical, parts, etc. (typical disclaimer). If the panhead conversion works as good as it did on my 45 I will write this up in my AMCA Chapter’s newsletter to get some volunteers to try it.

[t-bone]

3brush gen

ok here is how i check charging on my 50 pan i put a amp gage inline on neg side of batt with ign. on no lights it shows -5 amps turn lights on -10 amps. start bike now shows +4 amps turn lights on shows +3 amps. third brush is adj. all the way to plus side. i think this means it is making 13 amps at fast idle with lights on with original headlight,t3, or 4006 headlight am i anywhere close? thanks

[RvP]

Looking Good

It’s hard to tell what you have so let me start with the fact that you are measuring +3 amps with the lights on and engine running means the battery is charging – this is good, very good.

A couple of points first…..when I check the lighting load I do it with the points open. That eliminates the current drain of the ignition coil plus it will not heat up the coil or the points. The -5 amps you measured sounds like the points were closed. If the points are open you should measure under 1 amp which would be just the load of the generator and oil warning lights. Since you have shown there is a +3 amp charge going to the battery with the lights on the rest of this is just academic at this point.

Using my 45 with the springer bulb, assumed to be the same current draw as the stock 7” sealed beam, I measure -5.47 amps with the points open, low beam, rear running light and speedometer light. You measured -10 amps total. Given you were measuring -5 amps without the lights on I assume the points were closed so the -5 amps was the draw of the coil. This means your lighting draw is about -5 amps total which is in the ballpark of my 45. This is good also, means you must have the correct 7” sealed beam headlight.

This sounds like a really, really good 32E or 52. With the third brush closest to the plus side (counter clockwise) is the minimum output setting. Moving the third brush to the negative side (clockwise) increases generator output. With your third brush set all the way to the plus side and you are measuring 4 amps at the battery is slightly high. The proper setup for a 32E is measuring the current out of the generator and moving the third brush to set that current to 4 amps. If you are measuring 4 amps at the battery the generator has to be putting out more than 4 amps since the generator is feeding the ignition coil and the battery.

The only harm I see is 4 amps into the battery may overcharge the battery causing electrolyte loss. Since you have the third brush all the way to the plus side you cannot reduce the current any further. Keep an eye on the water level in the battery more frequently than usual and look for signs of it boiling over and spewing acid out the vents.

I think you are setup pretty good with the generator and the lighting load. I would not conclude that your 32E is putting out 13 amps. I know you concluded that because of the -10 amp load without the engine running and then +3 amps with the lights on and the engine running. If you made your measurements with the points closed then you have an additional current draw through the ignition coil that is not constant when the engine is running.

With the engine running the points are open for some period of time to make the spark. They remain open for some time to prevent the coil from saturating when they close to charge the coil. I have not figured this out but it is some duty cycle that will average less than 5 amps for the ignition coil when the engine is running. I think this is throwing off you concluding that the generator is putting out 13 amps, may be closer to 8 amps. Best way to tell for sure is to put the ammeter between the generator and the cutout relay.

From what you have written you are in good shape, just keep an eye on the battery water. Remember, if everything is working fine then don’t touch it, regardless of what anyone, including myself, thinks!

[t-bone]

thanks for the quick answer. i said it wrong when i told you all the way to the plus side i meant the third brush was at the end of its adjustment clockwise. as far as the battery i put a sealed 14 amp hr interstate batt inside of an old wisco i gutted out i,m planning on riding this bike to wauseon in july just trying to get my ducks in a row as it is about 400 miles one way. thanks again.

[Perry Ruiter]

The same folks that make that wonderful 12 volt regulator that looks like a cutout also make a 6 volt version. I'm sure Kurt at 45 Parts Depot can supply one. I've never used one but given my positive experience with their 12 volt regulator I don't hesitate to recommend it for those wanting to stay 6 volts. Indeed a two brush conversion with a regulator is the best solution for folks sticking with a 32E (whether 6 or 12 volts) ... Perry