Electrical Problem With 6 Volt 3 brush

[ottoa]

Perry,

After further research and testing, the system is acting like the battery is not connected. Several sources indicate that part of the battery's job is to hold the voltage under control, about 6.6 volts. I have power to the coil when the switch is turned on, however, once the engine starts, at idle the voltage can drop to 5.5 volts without the idiot light turning on, and then move up to over 8.0 volts as the throttle is increased. As stated before, this generator and relay were tested together - 2,500 rpm, 4 amps, and 6.6 volts and the light goes off at 6.3 volts. I have checked the battery with a hydrometer and shows in the green at about 1.273 all cells. Is there another way to check the battery to see if its good under load?

Otto

[Perry Ruiter]

Otto - I would think any good garage could load test a battery. Where are you getting the 5.5 reading? At the generator or at the battery? Have you tried disconnecting the battery positive and verifying with a meter no resistance from it to the cutout BAT terminal (with the ignition switch on?). As I recall you've run a ground wire directly from the battery negative post to the generator. With the bike running try also running a wire from the battery positive post to the generator relay terminal. This definitely puts the battery in circuit (don't forget to disconnect when you shut the bike off). Is the voltage now controlled? ... Perry

[P.A.G.]

Originally posted by Perry Ruiter
Otto - I would think any good garage could load test a battery. Where are you getting the 5.5 reading? At the generator or at the battery? Have you tried disconnecting the battery positive and verifying with a meter no resistance from it to the cutout BAT terminal (with the ignition switch on?). As I recall you've run a ground wire directly from the battery negative post to the generator. With the bike running try also running a wire from the battery positive post to the generator relay terminal. This definitely puts the battery in circuit (don't forget to disconnect when you shut the bike off). Is the voltage now controlled? ... Perry

Did you flash the field coils? As I recall it's recomended by the manual to mometarily jumper between the BAT and GEN terminals on the regulator when the generator has been removed and then reinstalled. This corrects the generator polarity. If the polarity is reversed it can cause all kinds of problems. Be sure to consult your manual before doing this to make sure it's done properly.

[ottoa]

Perry and all,

P.A.G., this is a three brush generator with cutout - no regulator. Perry, the 5.5 volts was at the battery. I did check the positive battery wire to relay BAT terminal with the switch on - .001 ohm or less. I hooked up the generator directly to the battery and jumpered the coil, no switch or cut out and started the engine. Voltage readings: idle - 6.3 volts , fast idle - 7.2 volts, road speed - 8.0+ volts. Left battery off charger for 7 days - 6.3 volts after 1 day, stayed there the rest of the week. I have tested the VOM with a percision resistor, checks out ok. Is there a battery problem? I have checked all of the switch terminals, current flows in the different circuits, and the grounds and all appear to be within reason. This last test has just about finished me off. I am going to contact the outfit that tested the generator and cutout and see if they used a larger 6 volt battery for the test, they do mostly car generators. The battery is a new in August Harley Classic 6 volt.

[Perry Ruiter]

Boy - sure sounds like the battery doesn't it. I think you were going to replace the battery before I proposed the bad ground theory. Sorry I spoke up. Try swapping batteries with a friend (or just buy a cheap (~20-30$) 6V gell cell) before springing for another "real" battery ... Perry

[kurt seifert]

Same problem with high voltage

I had the same problem with my '47 FL - burning out head and taillights. If I revved the engine with the lights on, the brightness would increase with the rpm's, and I would burn out bulbs right in the driveway doing this. I installed a solid state relay, checked all wiring, and adjusted the 3rd brush for less generator output. None of it helped. I read the above discussion, saw that it ended when you suggest he try a new battery. I had a new battery for another project, and gave it a try. Before I swapped batteries, I compared the headlight brightness while not running, to my '46 U. The U's headlight was a bright white light, while the '47 FL's was a dimmer orangish yellow. I installed the new battery, and the problem was solved. 7 year old battery with about 1100 miles on it. Looking back, I now realize other symptoms, such as an anemic horn noise, and rough running at higher speeds. All better now. Kurt Seifert