votage regulation

justind · Post by **justind** » Thu May 29, 2014 10:54 pm

hello,
I am new to the forum and recently inherited a 66 ca77. Got the bike running well put a new battery and after running it around for a while my battery went bad. Putting a meter across the leads i am finding at, i'm going to say 3k, my output is 18-20 volts. Ive been reading on the forum about the kohler engine regulator/rectifier and have decided to do the conversion but i just wanna get it straight, what was originally used on the bike as a voltage regulator? I figure there had to be something to regulate the voltage?
thanks

brewsky · Post by **brewsky** » Fri May 30, 2014 5:34 am

There is no voltage regulator.

The charging system is "balanced", with an extra stator winding kicking in when the ignition switch is turned to "headlight on" position.

See wiring diagram in electrical/wiring section.

SWARDLAW · Post by **SWARDLAW** » Mon Jun 02, 2014 11:07 am

I've wired my bike to have all the charging coils working all the time. I also make sure to not run the bike with the headlight off. I've also added the Kohler regulator and it works great. I run a very small AGM battery and the system has not cooked the battery in over a year. I don't use the electric start so I really didn't need a battery with alot of cranking amps. For me this ystem works great.

cadman · Post by **cadman** » Tue Jun 17, 2014 9:34 pm

The alternator (actually stator) has three pairs of two coils. One set of coils is used for running without the headlight. When the headlight is switched ON the other two pairs are connected to the rectifier. This gives you full charging capacity

How many total volts you will get is usually a mystery. Could be 13 could be 20. In most cases you are either under-charging or over-charging the battery. The Kohler is a modern day combination regulator/ rectifier that solves this problem. Simply tie the total alternator output to it and it should be fine.

redblk63 · Post by **redblk63** » Wed Jun 18, 2014 7:10 pm

On the other hand, some of us have used the Honda setup for decades with no trouble, other than replacing the stock rectifier with a modern $4 one from Radio Shack. The stock one allowed a small trickle of reverse current that discharged the battery if not ridden for several days.

Anyway, i am interested in the conditions of your measurement where you got 18 to 20 V. If this was AC voltage across the pink to brown or between the yellow to brown wires from the alternator with them disconnected from the rectifier and battery, 18 to 20 V sounds about right. If it was DC across the battery terminals, yikes!

Please describe your measurement.

Cheers,
Larry

cadman · Post by **cadman** » Wed Jun 18, 2014 9:06 pm

Any voltage measurements whether the direct AC from the alternator or DC from the rectifier seem to be a mystery. Normal AC voltage I see from the alternator on fairly modern bikes from the early 70's and 80's is 45 to 65VAC at about 5000 rpm. All else being correct this can result in DC charging voltage in the 13.5 to 14VDC.

All of my measurements on the Dream using two different stators and three different rectifiers is well below what is required for adequate charging. Less than 30 VAC and less than 13VDC. The system as it is now is a bit hit and miss - Either under-charge or over-charge the battery. Their own shop manual indicates a charge rate of 2-3 amps maximum which is not enough.

So if you are not attentive to the problem you will have battery problems.

redblk63 · Post by **redblk63** » Thu Jun 19, 2014 11:17 am

I agree about the element of mystery in these measurements. That is interesting information about the CA, but to me any charge rate to the battery that is above 0 Amps will keep it charged.

Of course, I always take care to not keep the brake light on when stopped (front brake only), and switch off the headlight when stopped for longer than a few seconds.

My Honda CB77 Service Manual, which you can find free on line, has some interesting plots on P 153 and 154 showing the charging/discharging current to the battery vs RPM for lights-off vs lights-on. At 3000 RPM, which I consider my minimum while riding, there is +2.1 Amps charging the battery with the lights off, and +1.3 A with the lights on. Of course, there is more charging at higher revs.

The crossover to battery discharge occurs at about 1500 to 1700 RPM for lights off and on, with max discharge about -3.5A and -5 A, respectively.

On P 152 they mention "...magnetic weakening of magnetic iron preventive measures have been taken in the course of design."

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votage regulation

votage regulation