CDI massive voltage drop with headlight on

[Hyperballsmcgee]

Hello all, I've got an 81 that at one point in time was a heritage special. now it's a pretty much stripped swingarm bobber. anyways I've got Hugh's new CDI kit on it as well as one of his new capacitors, the bike runs phenomenally and charges GREAT, however, all is well until I turn the headlight on under load. the only "accessories" on this bike are a head light, taillight, voltage gage, and an LED strip under the tank that illuminates the engine. I can kick the bike over, idles and charges great, taillight and stop light both work fine, but when I turn on the headlight all seems well and the gauge still reads around 12 volts, I go to ride it, and the voltage dumps off. turn the headlight back off and voltage comes right back. I checked with a meter for an exact reading when it was acting up and I'm only getting 6 volts with the headlight running. I tried removing the light bulb from the voltage gauge, putting a low draw led bulb in the tail light, turning the led strip under the gas tank off, and even daisy chained a second capacitor in, and still get a voltage dump with the headlight on. I thought maybe a bad ground so I made up a new ground strap for the headlamp and ran it straight to the frame and it has not helped. any ideas?

 

[Hyperballsmcgee]

headlight is the factory sealed beam with an "on-off-on" switch controlling high off and low

 

[650Skull]

I would suggest you contact Hugh. It is a new product and as such there is no instructional information on the web here or his site.

 

[Hyperballsmcgee]

Hugh's on vacation right now so this was the next resource.

 

[Hyperballsmcgee]

anybody?

 

[650Skull]

Maybe a diagram of your loom so someone can trouble shoot it.

 

[Hyperballsmcgee]

kind of messy and not EXACTLY in order but here's how it's wired. I didn't do every single wire for the ignition, but the ignition pickup wires go to a plug on the CDI box, then from the box to the coil

 

[Hyperballsmcgee]

and again, voltage is GREAT until you turn the headlight on. and yes it is wired correctly I've quadruple checked it and the plug is labeled high low and ground

 

[figure8]

I'm no expert by any means in this regard, but wouldn't a voltage drop indicate you're putting to much a load on the cap?

 

[retiredgentleman]

Your diagram shows 4 connections at the capacitor. I'm don't have a lot of knowledge of PMA's, but I think there should only be 2 connections, for the positive and negative at the capacitor.. Are there really 4 connections or are there 4 wires connected to 2 terminals?

I suggest you replace the capacitor with a battery for testing purposes. A battery can supply a much larger amount of current as compared to a capacitor. The capacitor may be too small or it may be defective.
What is the wattage of the headlight, and are you switching on high beam or low beam.?

Very poor customer service to not have a typical wiring diagram on his web site.

 

[figure8]

A sparx cap has 3 connections, 2 pos 1 neg. I f he has Hughs cap, it has 2 pos 2 neg.

 

[Hyperballsmcgee]

Hugh's cap has 2 positive and 2 negative. I thought it may have been too much load on it but I tried it with two identical capacitors daisy chained in unison and powering ONLY the headlight. I'm thinking either the headlight is simply too much draw or possible short in the switch.

 

[retiredgentleman]

"Daisy chain".......................not sure what you mean? I hope you did not connect the 2 capacitors in series, as that would reduce the capacitance. The 2 would have to be connected in parallel, to increase capacitance. So what wattage is the headlight?

 

[Hyperballsmcgee]

what do you mean in parallel? stock headlight I believe is 40 w

 

[BigJohnParts]

What is the wattage of the headlight? Typical is around 55-60 watts...

 

[Hyperballsmcgee]

are you saying to Y off the regulator leads and go to each capacitor individually and have say one power just the headlight and the other power the bolt gauge and taillight?

 

[retiredgentleman]

what do you mean in parallel? stock headlight I believe is 40 w

Electrical parallel connection means + of one capacitor wires to the + of the other cap.and - of one connects to - of the other cap.

 

[Hyperballsmcgee]

that's how I had it. I for some reason am having trouble putting it in words so I'll draw a picture and post in a second, regardless of that, either way I had it set up there was a big drop in voltage only with the headlight on

 

[Hyperballsmcgee]

 

[TwoManyXS1Bs]

My two cents. There will always be some form of voltage ripple on alternator powered lines. Sometimes caps paired with loads create resonant frequencies, that may be within the reactive/corrective zone of semiconductor devices, like the regulator, and it may be responding unfavorably.

A simple test would be to rewire, to un-daisychain the caps from the load.

But, RG's suggestion is the better method:

I suggest you replace the capacitor with a battery for testing purposes...