Need some electrical advice
HDF Community Team
Joined: Dec 2005
Posts: 5,397
Likes: 2,599
From: NC USA
Originally Posted by 0maha;
Another thing to note: When I was putting this together a few months ago, I couldn't get any of this to work [i
Another thing to note: When I was putting this together a few months ago, I couldn't get any of this to work [i
until I hooked up the headlight. It was as if the VR needed a certain resistance load on it before it would "wake up".
Anyway, based on all of the above, I'm leaning toward the opinion that the VR is shot.
But I'm also wondering if I killed it because of the way I've got this thing set up. The way the lights dim, then brighten when the brake light comes on, makes me wonder if I should install a resistor somewhere in the system just to increase the load.
Any thoughts, advice or ideas?
Anyway, based on all of the above, I'm leaning toward the opinion that the VR is shot.
But I'm also wondering if I killed it because of the way I've got this thing set up. The way the lights dim, then brighten when the brake light comes on, makes me wonder if I should install a resistor somewhere in the system just to increase the load.
Any thoughts, advice or ideas?
The difference between the CE regulators is probably an internal power resistor across the Zener diode (which is what regulates the voltage). In a typical system, the battery is in fact that resistor. With a magneto ignition the only load was your head and tail light (when on) so eventually little/no load caused the Zener to overheat trying to throw off the extra voltage and eventually fail. That's why the brake light brightened the headlight. It was enough extra load to give the Zener a break but eventually the heat killed it and/or a diode or 2 explaining the 5v VR output.
The "battery eliminator" (storage capacitor) is only good for starting a point/coil ignition system (by holding enough electricity from the charging system when kicking over) to light the coils. That worked fine with the old British bikes but their alternators only did 5-8 amps at best and they used a massive Zener diode/heatsink. I'm neither an electrical engineer nor genius, but thru the '70's and '80's I rode only homemade Triumphs so I am on a first name basis with "Lucas - the Prince of Darkness"
Last edited by t150vej; Oct 10, 2018 at 08:58 AM.
Stock 2 wire input HD regulators are nothing more than a diode rectifier bridge and Zener diode which regulates by converting extra voltage into energy (heat).
The difference between the CE regulators is probably an internal power resistor across the Zener diode (which is what regulates the voltage). In a typical system, the battery is in fact that resistor. With a magneto ignition the only load was your head and tail light (when on) so eventually little/no load caused the Zener to overheat trying to throw off the extra voltage and eventually fail. That's why the brake light brightened the headlight. It was enough extra load to give the Zener a break but eventually the heat killed it and/or a diode or 2 explaining the 5v VR output.
The "battery eliminator" (storage capacitor) is only good for starting a point/coil ignition system (by holding enough electricity from the charging system when kicking over) to light the coils. That worked fine with the old British bikes but their alternators only did 5-8 amps at best and they used a massive Zener diode/heatsink. I'm neither an electrical engineer nor genius, but thru the '70's and '80's I rode only homemade Triumphs so I am on a first name basis with "Lucas - the Prince of Darkness"
The difference between the CE regulators is probably an internal power resistor across the Zener diode (which is what regulates the voltage). In a typical system, the battery is in fact that resistor. With a magneto ignition the only load was your head and tail light (when on) so eventually little/no load caused the Zener to overheat trying to throw off the extra voltage and eventually fail. That's why the brake light brightened the headlight. It was enough extra load to give the Zener a break but eventually the heat killed it and/or a diode or 2 explaining the 5v VR output.
The "battery eliminator" (storage capacitor) is only good for starting a point/coil ignition system (by holding enough electricity from the charging system when kicking over) to light the coils. That worked fine with the old British bikes but their alternators only did 5-8 amps at best and they used a massive Zener diode/heatsink. I'm neither an electrical engineer nor genius, but thru the '70's and '80's I rode only homemade Triumphs so I am on a first name basis with "Lucas - the Prince of Darkness"
The only open question that remains is the capacitor. CE is quite clear that their "NB" model regulators need one ("A battery eliminator must be used. A magneto is required for ignition."), but your explanation suggests otherwise. At this point, I can't see that it could hurt anything, so I guess I'll mount it up and see what's what from there.
Thanks again!
HDF Community Team
Joined: Dec 2005
Posts: 5,397
Likes: 2,599
From: NC USA
Thanks for the flowers Bro.
Yeah, I don't understand all I know about all that... and even less able to type it all out. Anyway, yes I would use the capacitor for warranty protection that you hopefully never need. And it'd probably keep your lights from surging/pulsing. That's some impressive old school Iron you got going on there. My compliments!
Yeah, I don't understand all I know about all that... and even less able to type it all out. Anyway, yes I would use the capacitor for warranty protection that you hopefully never need. And it'd probably keep your lights from surging/pulsing. That's some impressive old school Iron you got going on there. My compliments!
You meant "battery eliminator", but you're right. I'm going with their advice.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,897
From: Bedford UK
I've owned two new BSA bikes and while they both had zener diodes they were hardly 'massive'! They were actually quite small, but were set in a finned cast alloy heatsink. I had to replace a couple over the years. All they did was cut off voltage from the alternator above a preset level, I guess around the 14.6 we're all familiar with. All British bikes with zener diodes also had a battery. I rode British bikes for many years, all with Lucas stuff and the darkness thing applies to the 6 volt systems, not the later 12volt ones, which in their day were fine.
Evo forum Rules!!!
Truly appreciate the offer, but for warranty preservation purposes, I think I better stick with the one from CE.
Thanks!
Truly appreciate the offer, but for warranty preservation purposes, I think I better stick with the one from CE.
Thanks!
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