Headlight dims when brake light is on?…
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Also the horn and indicators do the same…
I don’t understand why it does this, as I understand it the head, tail & instrument lights are A/C powered. As so they shouldn’t be affected by the DC battery powered horn, indicators, neutral & brake lights?!
Does the A/C part have its own earth that goes back to the stator? (I know the rectifier discharges the power made by the A/C lighting coil if the lights aren’t on, and I guess it regulates the A/C to 12V?) or does it share with the Direct Current? I know that the A/C tail & DC brake bulb share a common earth. I’m wondering if a bad poor earth somewhere could be causing it…I don’t know if all years of Dtr have this dimming, or just the early ones with 3 coils on the stator? (1 for lighting, 1 for ignition & 1 for battery charging)
Help!!!….
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@SpookDog
Ere not sure where your getting your info from, but all the lights on your bike and all cars n bikes for that matter are DC voltage. The engine and generator will produce an AC voltage and then this goes through the regulator/rectifier and converts that to a DC voltage.As the crank turns this generates power, as an AC voltage and this could be anywhere between 20-40 VAC and is no good for us and needs to be smoothed and converted to 12-14VDC for the lamps relays power valves and electronics to work.
On tick over the headlight brake lights etc will work and flicker to an extent and when you rev the bike the generator produces more power and this is converted into DC power. As such your lights will increase in brightness. This isn’t a bad thing it’s just that the system will have say 15-20% in built tolerance and worse case scenario 12v plus 20% will be 14.4v which is enough to brighten your lamps. If your making 13.5v this can go upto 16-17VDCIf your really concerned make sure your battery is fully charged and connected, then measure the voltage of the battery with everything turned off. Then measure the voltage with the ignition turned on lights off, then turn the lights on, side, then high beam and pass light, you should see the voltage drop from 13.5VDC to possibly 11.5VDC depending on the state of your battery. Then do the same with the bike running all of the reading you have measured earlier can increase by 15-20%.
If the voltage increase is by more than that, to say 14-18VDC it could be that your rectifier is failing and not reducing the input voltage enough for everything to work OK within tolerances. I don’t know exactly but it does say in the Haynes manual what the tolerances are and advises for replacement if parts are not within these tolerances. But if my lights were on but low on tick over and brightened when the revs picked up I wouldn’t be that bothered.
But bear in mind don’t compare anything electrical on bikes from 20-30 years ago to bikes now as components and tech have jumped leaps n bounds since than. With the use of LEDs bikes and cars only need a quarter of the power that was needed years ago. I’ve got 5 batteries on charge on rotation and over the winter with the cold weather just after a few days these can drop from 13.2v to 12v. -
That’s what I thought as well. Do a bit of searching on older bikes. I’m sure modern bikes and I know cars are all dc and run through the battery. I’m no expert by any means and all I can gather is gleaned from the web…
I think the dtre’s may run the lights through the battery , that’s why they’re superior to the old ones that dim with the revs…
I’m not sure if thr RR converts all the ac from the stator or just what is needed to charge the battery…
Whichever it is I still don’t understand why the lights dim when the battery operated brakes lights, ect come on. The battery is a brand new 6ah instead of the standard 3ah (iirc) -
One thing I should do is disconnect the battery and see if the horn, brake light & indicators work without it. If they do it’ll mean that they share the lighting coil to some extent. I know that the power valve servo will not work with the battery being dead from past experience. So I kinda assumed that the other battery powered ancillaries wouldn’t work either…
My stator plate has three separate coils on it. 1 for ignition, 1 for charging the battery & 1 that runs the lights. As the battery doesn’t supliment the lights I assumed they were separate circuits…There are at least 3 different kinds of stator that I know of and I’m not sure about any similarity or the difference between them. I think the later at least is something called 3 phase. But like I said I’m no expert. When it comes to electrics I’m like Marie Keller trying to do a Rubics cube
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@SpookDog
I wouldn’t recommend disconnecting the battery and seeing how things run as the alternator can kick out high voltages that will damage the electrics. The battery not only provides power when you need it for starting and power valves but as a buffer to soak up excess voltage. It there to smooth the voltage. If you’ve installed a bigger battery you may have already damaged the system as the bigger battery will draw bigger current (Amps) and damage the charging circuit. Which will in effect change the tolerances so when your system was putting out 14v it could start putting out 18-20v which will kill the battery and the electrics. -
@SpookDog
3 phase is totally different and thankfully you won’t find this on a motorbike or car for that matter. It’s all to do with the phase cycle and how it’s produced. Normal house wiring is single phase using 2 wire with 1 as a return path (Neutral) 3 phase uses 3 wires with neutral. Singe phase produces energy at 90’ and 270’ where 3 phase produces energy out of sinc at 120’ and therefore more constant over the 3 wires. -
“ The output from the stator on most modern bikes is three phase (hence the 3 wires) alternating current at a peak voltage well over the 12-14V DC voltage that your electrical system requres”
This is the kind of stuff I’ve been reading through to try and glean information that I know nothing about. My bike isn’t modern, it’s 35 years young now!
But I am pretty sure the battery is in no way a buffer (from what I’ve read!
) That’s the RR’s job to turn unused AC current into heat…If I’m wrong fair enough, but please help me out by pointing me towards some proper info on the web that can be credible and backed up by other sites info that I can try and learn from.I don’t understand electrical systems and the way they have changed over time. If you have a genuine knowledge about it please help me, cause I’m kinda lost with searching the web
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Quite a few bikes run solely AC, kawasaki Kdx200's do. They don't have a battery, just a voltage regulator. And there lights are powered by AC voltage.
Think some honda trail bikes run both AC and DC systems on the same bike. The very early dt's could be the same?