Charging woes

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Mar 19, 2005
I,ve just finished building a Atlas Cafe Racer but am having a charging problem , I have a new stator, good rotor, boyer MK3, and a new Tympanium reg/rectifier. I,m only getting 10 to 11 charging volts , I,ve replaced the tympanium with another new one but no difference , I,m wondering whether this all I can expect from this setup, ANY advice will be appreciated.
you should have at least 14 volts, to charge a 12 volt battery...make sure the clearance between the stator and the magnet is there, if it touches, it will load all the voltage to the frame, and not the battery.
bad ground, wire touching somewhere the frame? Where are you measuring the voltage? across the poles on the battery? does the voltage increase with engine speed, like it most likely should? Can't be much wrong....
is the rotor on straight, loose? Someone must know what you should measure straight off the wires, out of the primary case, would be alternating current,before the rectifier, but ther must be a way to localize the problem.
I have the rotor fixed to the belt drive pulley. I read in a manual that 9volts AC should be coming out , and thats what mine measured though that doesnt sound right
Check to see if the wires are good at the exit point of the stator, sometimes you can get a "crack" and "bleed" there. Did you build the loom yourself, I am thinking you did. Was it all new wire or did you "cut and paste"? I would suspect a suspect ground first. Do us a favor and keep us posted! I love a good electrical solution when it finally happens.

double check wires ar stator for tiny breaks in insulaton.
It charges 10 t0 11 volts at the battery, 9volts AC at the alternator . every thing is brand new ,there certainly doesnt appear to be any shorting any where , I,ll try another new stator
A chiltons manual I have says 9Volts AC should be at the Alternator , mine is brand new ,I wouldnt think the wires would be cracked but I,ll try a new one . No one can verify what should be coming from the Alternator AC.
This is common when changing over to podtronic (sp)or tympanium You would like to see 13-14 volts @ 3000 rpm then have the internal zener kick in and keep it there. An amp check is really what's important for the real world. Just put an amp gage were the fuse goes in the system. Bikes off to start. Turn the key on and you should see about a three amp draw for the Boyer, fire it up at revs to 3500rpm you should see three amps positive. Turn on all the lights head and tail you better have 1 amp left over or your not going to be chargeing the battery. If you have a problem you can run a LED tail light they draw one third of the current required for a standard tail light. norbsa
Thanks Greg, I just asked Reg to check his Alternator AC output but I,ll dig up an amp gauge and do as you say,
Don (Brisbane)
the nearest I could get to a 1ohm/50watts resistor is a 1.3ohm/50watt ,I dont know if this will make a big difference but all I,m getting from the Alternator is 4.7v AC, I changed the stator to another new one and got the same result. I,ve checked the rotor magenitism and its as good as other ones I,ve got lying around.
I think I may have found the problem, I,ve removed the rotor ,something I didnt want to do as It is spigoted and doweled to the pulley, but now its off and the magenitism is definitely not as strong as others I have., I thought it was as good as the others but its not, I now have to machine another one to replace it. I,ll keep you posted.
Sure was the old rotor I used with not enough magnetism. now I,m getting 14.2 volts. The only part that wasnt new let me down.
Thanks for the update. We all appreciate hearing how these conclude.
what did you have to machine? I had a rotor on a 1941 cycle remagnetized once...but how would machining do the trick, or did you take a non-stock rotor and adapt it? Just curious....
No , my rotor is spigoted to the front pulley which required some machining , when I realised the rotor had no magnetism I replaced it which required machining of the replacement rotor, Got it.
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