LED lighting flicker (WD forte?)

[stinkwheel]

On my Minsk 125 which has a single phase 12V DC "charging" system with no battery. Standard reg/rec. LED bulbs throughout. The ignition system is totally seperate.

The lights have a barely perceptible flicker at idle. A much more noticeable one as you rev the engine up. I checked the output voltage and it was pretty much nailed to 14v. Analogue meter and the needle seemed steady. The taillight LED bulb popped (may be a red herring, it was a cheap and nasty amazon one)

I tried fitting a 4,700uf 50V capacitor paralell to the circuit. This seemed to make no difference.

I fitted an incandescent taillight bulb to see if it was actually a bad connection vibrating. This lit up normally and steadily AND the flicker on the other lights stopped.

I took the incandescent out (hot, hot hot!) and the flicker started again. If I sound the horn, the flicker stops.

It seems they flicker unless there is an added load in the circuit. The instrument panel lights do it too. Maybe the LEDs and lack of load are causing some funky effect with the reg/rec?

WD forte mentioned the capacitor may be a bit on the big side? Maybe fit a smaller one? I'm wondering what would be a good value if that is the case?

The simple solution would be to just use an incandescent taillight bulb, and this is what I'll do for the MOT. I'm just concerned the flicker might damage the other bulbs if the taillight isn't on.

Maybe fit a ballast resistor paralell to the capacitor??
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Bhud]

Tbh some of the filter circuit solutions you guys were talking about seemed a bit strange.

[stinkwheel]

It's got nothing odd in there. Output from the reg/rec goes straight to the main fuse and then the lighting. The only slightly odd thing is a couple of diodes so the single flasher tell-tale will work properly without lighting up both sets of flashers but that's only connected when the flashers are on.

The capacitor is connected where the battery would be.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[WD Forte]

In general bigger capacitors dont react (charge/discharge) as fast as smaller ones so the 4700 may be a bit on the large side

its normal practise in power supplies to use smaller caps in parallel with a large one to smooth out higher frequencies

I used a 330uf electrolytic cap on the moby and it worked well enough considering the very spiky output from its single coil stator, but the guy took it away before I could fine tune it and hasn't complained since.
Had it lived here, I may have added/swapped caps to get a better smoother output.

Without seeing the output on a scope, its hard to say anything for sure but a smaller cap would be my first thing to try
and add say a 47uf/50v across the led power terminals?

To refresh my memeory i looked up the Moby experimends I did and
the spiky waveforms I had to deal with

This when i first started to try and improve the Moby
with moderate improvements
https://www.bikechatforums.com/viewtopic.php?t=324407

Later when I went full retard on it and converted it to a 12v DC system with cdi ignition, note I only had one single poxy coil to play with for lights but the 330uf cap help a lot

https://www.bikechatforums.com/viewtopic.php?t=334589
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bikers smell of wee

[Easy-X]

It doesn't hurt to put a few caps in parallel e.g. 470uF + 100nF. In electronics (and one could argue LEDs are more electronics than electrics) it's usual to have an electrolytic paired with a ceramic to smooth things out.
____________________
Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[stinkwheel]

[WD Forte]

100 nano caps are common in electronic circuits but this is for much higher frequency circuits (mega hertz) than what we're dealing with here
Let's say we have one winding/coil and one magnet
you'll get one pos and one neg pulse per rev.
Half wave rectifed thats 16hz @ 1000 rpm and 166 hz at 10,000 rpm
full wave rectified 32 to 320 hz
Multiple coils and multiple magnets will produce more pulses of course
I did calculate what the old CX stator was doing once but can't remember details now, only that it was in the 200 Kiloherz range
IIRC it was 18 coils and 6 magnets.
Even so, that's slow in electronic terms and as I vaugely recall
from another experiment, I couldn't discern any flicker from an led above say 40-50hz
which conforms with your lights looking ok at higher speeds
A 20 ohm resistor will burn off 0.6A/7.2 watts at 12v

Not sure you really need one, but as long as the stator has the spare capacity and its rated at 10watt or above it shouldn't do any harm.
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bikers smell of wee

[A100man]

Probably not want you want but how about a small battery in there..?
Maybe the Rec/Reg is 'expecting' one. Useful for stalls too.
____________________
Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[stinkwheel]

The kit is supposed to be used without a battery, these bikes never had one. I guess it's also supposed to be used with normal bulbs and I suspect it would have no issues if that was the case. I particularly wanted an LED headlamp just because they are so good compared to a 40W tungsten.

It's rated for 120W so I should have ample excess capacity.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[WD Forte]

A battery does acts like a big cap and vice versa
If you look at a say a car or bike battery on a scope when running, you'll
quite often see a small ripple voltage you were unaware of visually.

I'ts a thing I hadn't thought about much until recently when I
bought a battery tester that checks for this to see if its within acceptable bounds (a few millivolts)
plus the hoo hah with that YBR where the bad connection on the RegRec caused the ECU to false trigger coil warnings.

In the case of Stinkers commie 2 smoke, I reckon an additional small cap at the led devices terminals could well do the job of smoothing the supply.
____________________
bikers smell of wee

[stinkwheel]

It also occurrs to me that the kit had a reg/rec with it that looks like one of the ebay Chinese ones but might also be Russian.

I wonder if fitting a mosfet based reg/rec would be a good plan?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[slowasyoulike]

[WD Forte]

[stinkwheel]

I was more wondering if the output would be cleaner. As you say, there's sufficient output behind it.
https://lh3.googleusercontent.com/pw/ABLVV87FbvEvN4MZbXtGZvAgxAZyvuNChytYCM_hlWxkIv7vcSI7RzqkKE5CRQDoByynMubiT1KPVOXFbfBMdHFVFgnCPmjFnCcjxjpGqenzjCdjp2Fo5-LsOq8vILU9NmQmyGxUVsFbmCdMx4kgrZMxcWJa=w1547-h870-s-no

With two outputs feeding a single phase reg/rec.
https://lh3.googleusercontent.com/pw/ABLVV84zrC7s0O0Zpv66yFWcFqJfNtVGET_1VGhge-TvCqaLgPEs4DFD6GlJW7I3S9eAc4sUz139Y_oBSCWtRk-Y83POfBCNGSgjzp00KtVeP9LhlLTqS5vbaw9GdOB9wPjoS63mx4HI0VJ4oEyA2QZHu1Ep=w1547-h870-s-no

Got some caps and a ballast resistor arriving today so I can have a fiddle.

Oh, the other thing that occurred to me is it has an unsupressed ignition system. They were quite firm about not using a resistor plug cap. The ignition is self-contained (presumably that top coil).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[stinkwheel]

I've decided the shit-can all the LED bulbs other than the headlamp. It's the only one that conferrs any significant advantage on this bike. It seems happy when the other bulbs are incandescents.

It's supposed to be a simple bike and I'm getting uncomfortable with the amount of electronics lurking about which are fixing a problem that needn't exist. There is more than adequate power output.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[WD Forte]

Sounds like a good plan as the headlamp is the single largest consumer of power and by having an led headlamp and the rest stock
you have a nice simple system.
Simple is good, I like simple.
it conforms with another of me wee sayings,
'Never make anything more complicated than it needs to be'
____________________
bikers smell of wee

[A100man]

Chaps, since I'm in the process of dicking about with my diminuitive 2T (GP100 disk front end transplant onto the A100.) I'm also on the LED trail. Thing is I'm fairly sure my lamp, 25W/25W, is currently 6V AC direct from a dedicated alternator coil - can anything be done there?

we may have been here before
____________________
Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[stinkwheel]

[A100man]

[WD Forte]

Given enough time and money you can convert anything to anything
but if its just a better headlight you want, perhaps checking out what's
available in the 6V AC/DC led range would show options

https://www.classiccarleds.co.uk/collections/6-volt-collection

If you want go full upgrade to a conventional 12v DC system with battery,
my advice would be to start a dedicated thread to avoid confusion
take good pics of the existing stator/generator plate
find wiring diagrams of the exisiting system then
plan the work and work the plan forwards from there.
____________________
bikers smell of wee

[A100man]