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Discussion Starter · #1 ·
I'm adding a few upgrades to my Suzuki T20 (Super Six), to make this 53 year old bike a bit safer to ride.

Included in this is fitting some extra lighting. I upgraded the ignition and power generation to a PowerDynamo set up which gives out 180 watts instated of the standard ca. 80 watts.

I have now started fitting this , combined indicator and DRL, to make me more visible to other road users.

The lights work great when I test them without the engine running, but with the engine running the DRLs flash randomly. To be fair, the PowerDynamo system is not tested with LEDs, nor do the makers recommend LED use because they haven't tested things so I suspect that it is causing problems, maybe with a noisy DC output.

However, I'm wondering if anyone has had this problem and managed to solve it? Any help will be gratefully received!
 

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I know nothing about electrical stuff except enough to get me in trouble. But I'm wondering if some diodes of the right value would help stabilize things.
 

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Discussion Starter · #3 ·
Thanks for the thought. I'm not too hot on these things either, otherwise I would know better than to fiddle with something that was working fine!

Ironically, I suspect that if I had left the original charging system in place the LEDs would probably work fine, and they don't take too much current anyway :rolleyes:

I'm going to experiment with, for example, a direct ground to the battery rather than via the frame, to see if that makes any difference. I have some diodes, and can easily slip one into the circuit but I wonder if that will make a difference, given that the lights themselves are diodes ? No harm in trying, I guess.
 

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Maybe one of our electrical gurus will have an idea. We have several or at least did at one time. I'm not much into restorations and repairs but I think we have an electrical forum as well. If we do, you might need to ask there as well as some folks only watch certain threads.
 

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In this situation I would:

A) Try a CANBUS LED bulb - These bulbs emulate the resistance of a standard bulb. They're generally for cars/bikes with CANBUS systems but I have used them for other projects not involving a CANBUS where regular LEDs didn't work out.

B) Wire an in-line resistor. This gives you control of the exact resistance going to the PowerDynamo from the LEDs.

Looking at that eBay listing, I think it would probably be best to try Option B unless you want to try buying new ones.
 

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I wonder if a capacitor on the wires to the bulbs would help by filtering the DC.. I know some cars (Chrysler and jeeps) have that type of issue when converted to LED and a capacitor fixes it. Google "LED flicker capacitor" to see some of the types available.
 

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I was wondering about a cap but was sure if it was voltage or low causing the problem. Glad you electrical folks are jumping in.:thumbsup:
 
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Discussion Starter · #8 ·
Miss Mercedes, thanks for the suggestions. I want to stick with these indicators as I like the dual function front (triple at the rear - indicator, rear light and brake light), so alternative bulbs aren't an option at this stage. My understanding of adding a resistor is that it helps to fool flasher units into "thinking" that there is a normal filament bulb present, to get the correct flash rate, but it will also reduce the brightness of the light?

I wonder if a capacitor on the wires to the bulbs would help by filtering the DC.. I know some cars (Chrysler and jeeps) have that type of issue when converted to LED and a capacitor fixes it. Google "LED flicker capacitor" to see some of the types available.
Thanks, I'll look into that.
 

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When the correct resistor is used the LED should still get its full power. The only difference is that the LED puts a greater load on the electrical system. :)
 
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A resister would go in parallel, not in series, so that would not reduce the brightness, just waste power, tricking the circuit into thinking it was an old school filament bulb. That's the fix for signals not flashing correctly after LED conversions, I never heard of using it for a headlight or driving light but I suppose some circuits might be looking for the right current draw and acting up when they don't see it. It would negate any power savings though.

When I converted to LED bulbs on turn signals I changed to the correct LED rated flasher so i could avoid having to use resistors.
 
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I'm not exactly sure how diodes work but I've read read they are used to control the amount of juice somehow. Is it possible you need both a diode and capacitor to fix this problem? Like I said earlier, I know very little about this stuff. Just enough to get into big trouble. So that's why I ask rather than say that's the fix. Hope y'all understand that. I would bet you'll need to do a lot of current testing in order to give that bulb just what it's looking for. Does this bike have a computer anywhere that might be controlling things? The mention of CANBUS makes me wonder if that's the culprit.
 

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It's a very vintage bike so it won't have a CANBUS. I mentioned CANBUS LEDs because they have built-in resistors generally to satisfy computers but they can be used for other applications. LEDs are also pretty sensitive to voltage changes and spikes can easily kill them. I've found that having LEDs with resistors in them (or resistors inline) allows them to last far longer and they also appear to work better as well. I'm not 100% certain that'll solve OP's flashing issues but it's a worthwhile investment, anyway.

I'm not entirely sure what impact the PowerDynamo has on a motorcycle electrical system, but it appears to chew up enough LEDs for the manufacturer to warn about it.

Powerdynamo und LED lighting equipment
 

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Discussion Starter · #15 · (Edited)
Thanks for all the inputs. I won't get chance to look at it again until the weekend at the earliest so I won't be able to test any of your suggestions. I know, the suspense will kill you. Sorry about that :grin:

When I converted to LED bulbs on turn signals I changed to the correct LED rated flasher
. I did buy one of these, assuming that it would be needed. I haven't fitted it yet as it wasn't needed with only the fronts changed to LEDs. Maybe it will be needed when I add the rears. Or, it maybe that the flasher unit I installed originally can cope with LEDs, it being a modern unit? We will see!

You are correct, Miss M, they do warn about it so I won't go back to them and complain if I blow the indicators. I like a challenge, though, so I will keep at it and see if I can get a work around.

I thought I had posted this comment from the PowerDynamo guys in response to another customer having problems, but can't see it in the thread:

Remark:

We have not been able to reproduce a situation where our standard regulator delivers voltage high enough to destroy the LED, even without battery not.

The solution with the regulator with integrated condenser is difficult to understand, as the battery has a much bigger capacity than the condenser inside the regulator.

We therefore assume, that:

either there was bad wiring leading to intermitened disconnection of the battery during engine run which could result in voltage bursts - which surely would be smoothened by the alternative regulator.
or the customer had assembled a wire from the LED arrangement directly next to and in parallel to the high tension cable leading to the spark plug. On the ETZ a probable situation

NEVER ever lead ANY impulse wire directly in parallel to the ignition cable (HT cable)
My wiring does run alongside the HT leads as there isn't much option. So another thought is to try running the lights off the bike, connected directly to the battery, with engine running. If they work in that scenario it would suggest that a wiring re-route on the bike might fix it.
 

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Discussion Starter · #16 · (Edited)
I tried the simple approach today, in case the problem is that the wires run next to the HT leads. I took one of the lights off and connected it directly to the battery. Sadly, the light was even more intermittent with the engine running than it had been when installed.

I measured the voltage across the battery terminals with the engine running. It does fluctuate pretty rapidly between 13.6 and 14.2v. I never checked the original set up so I don't know if that fluctuated similarly, anybody got any thoughts on this? Do LEDs need a more regular voltage?

I don't have any capacitors to hand but will order some and experiment with the light attached to the battery, where the wires are easy to access. How should they be wired - I know very little about electronics so a dummy's guide would be nice ?

This is what the units look like installed:



 

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LEDs like as close to a constant 12V as possible. They're super sensitive to changes in voltage, something readily apparent when dealing with a vintage vehicle. I'd recommend a resistor wired in line so that the LEDs get closer to the voltage they need.

Here is a decent explanation of how to do it. :)

Motorcycle LED Turn Signal Resistors | Canyon Chasers Motorcycle Sport Touring

Additional resources can be found with a web search for: how to wire led resistor
 

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Discussion Starter · #19 ·
The resistors arrived today. They are quite large, so its going to be difficult/impossible to accommodate four of them in the headlamp shell (one for each lamp x2, 1 for each indicator x 2) and six at the rear end of the bike.

Could they work if included in the main feed wires (there are two) from the battery to the ignition switch, instead? Being an old bike there are not too many things running from the switch:
- horn
- indicators
- lights
- stop lights
- tell tale lights in the headlamp bucket.

As long as the resistors don't drop the voltage below 12v the headlamp should still be as bright (or should I say "candle-like" ) as before, and the horn should work I guess?
 

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Discussion Starter · #20 ·
I had a look at this again today.

I tried one of the resistors, fitted in parallel, and that made no difference. Should it have been in series?

I also tried this, thinking that if it regulated the voltage from the Powerdymamo to 12v it would be a neater solution as I could run all the LEDs via this (they are only 3 watts each so all four draw 1 amp).

That didn't make any difference, either. :frown:



Not sure where to go from here, maybe I have to accept that the Powerdynamo is just too much for LEDs to handle. Its a shame as it makes the bike easier to start and better running.
 
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