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01-08-2020, 03:07 PM | #1 |
No turn left unstoned
Join Date: Jun 2010
Location: leicester
Bike: M750
Posts: 4,559
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Warning light is dim after fitting led indicators.
I've been trying to neatly fit a set of panigale led indicators to my yr 2000 M750 for ages.
After much pondering I finally managed to attach the rear ones to the teatray without them looking like they'd been slapped on willy-nilly. Front ones were relatively easy. I know .. there should be pics at this point but I'm lacking in that dept, I'm afraid. Anyway, to get to the point .... I fitted an led-specific relay to correct the flash speed. This was also quite neat as it was exactly the same dims as the std relay so it fitted straight into the rubber strap thingy where the old one was. It was one of those with a speed adjustment knob so it was dead simple to reset the flash speed. So far so good and I thought that was the job done and dusted. It had taken some perseverance and I was close to abandoning the project on a few occasions but I persisted as a sort of memo of Buzzbomb because we had been discussing the issue over many months. Anyway, and here's the rub, the indicator warning light is now much dimmer than it used to be. In fact it is hardly visible in daylight on a bright day. Now there are those in the club who already know that I can sometimes be a tad forgetful about cancelling my indicators these days In fact this can be quite dangerous and it is something that I'm actively working on. The last thing I need is a dim warning light. So the question is, do any of you electric-savvy members have an explanation for this new dimness (the bike, not me) and better still any suggestions for a cure ....? So far, my thoughts are that one solution might be if I replaced the original flasher relay and corrected the flash speed with resistors instead, but that's not quite so neat as using the led-specific relay. I also considered replacing the bulb in the warning light with an led, but I've got no further with that than a vague pondering. Thanks in advance. |
01-08-2020, 04:03 PM | #2 |
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Hi, a couple of guesses, could there be a voltage dropper in the flasher to work with leds 4.8v, or the adjuster is reducing the 12v input voltage to set the flash speed, but the incandescent bulb in the dash on the output circuit isn't receiving 12volts
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01-08-2020, 04:46 PM | #3 |
Lord of the Rings
Join Date: May 2013
Location: Norwich
Bike: M900sie
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That would be my thinking too. I imagine the adjustment is stepping down the current and so depriving the warning light.
Easy test for this would be to wind the relay back up again, thus increasing the winker speed, but observing the brightness of the warning light at the same time.. Obviously not a cure, but an indicator as to watts going on. (couldn't help it!) Messing with the wattage of the warning repeater might not be any good? As far as I know the repeater is connected to the indicators both sides in series, and does not light the opposite side indicators because the resistance in the repeater prevents enough current from reaching the other indicators.. Or something like that? If you were to replace the repeater with an LED it might not work at all since LED's are very voltage sensitive and also polarity critical (ie, a diode) and I think the current needs to be able to flow either way depending on which side is switched on? I've probably exposed my slender grasp of what's happening here, but someone could probably explain it better or blow it out of the water? As an aside, would you consider an audible repeater? Perhaps it would be inaudible or not have sufficient current to work? Or just be too irritating?
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Last edited by Mr Gazza; 01-08-2020 at 04:48 PM.. |
01-08-2020, 05:57 PM | #4 |
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Join Date: Jun 2010
Location: leicester
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Thanks for your responses so far.
My thinking as to the cause of the problem was also along similar lines to your suggestions. I tried winding the flash speed back up but it seemed to make no difference to the brightness of the warning light. In fact I wound it between max and min flash speeds and could detect no change in warning light brightness. I have yet to fully digest the nature of the circuitry and also the likely effect of messing with the wattage of the indicator bulb. However a cursory glance at the wiring diagram would suggest that current needs to flow in each direction through the warning light according to which side (left/right) is flashing .. so yes (or do I mean no) it would seem that an led warning light will not work due to it being uni-directional. I have briefly considered an audible warning device but yes it would be annoying, no it might not be loud enough and also it doesn't fit with my minimalist design philosophy. My memory isn't so bad that a decent, bright warning light and a bit of focus shouldn't be enough. Looks like the led warning light idea is a non-starter though .. so you've saved me unnecessary time and expense there. I'm still wondering if a higher wattage conventional bulb might be worth trying. That might be just because my grasp of the situation is vague though. ps. the original bulb is a type T5 (also designated 286) and is marked 12V 3n OS ..... correction, the marking is actually 12 / 3n OS I have no idea what the 3n OS bit means. Last edited by utopia; 01-08-2020 at 06:41 PM.. |
01-08-2020, 06:22 PM | #5 | |
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This might explain the problem:
Quote:
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01-08-2020, 06:48 PM | #6 | |
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And for an example of what they mean by "reworking how the indicator light works", this is more complicated, but actually might be the "correct" fix; different symptoms, similar cause: https://www.customled.com/blogs/cust...d-turn-signals
Quote:
Even though you don't have this exact issue, I think this'd also fix the "dim indicator" issue - by providing a good path to ground for the bulb (or LED). |
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01-08-2020, 06:52 PM | #7 | |
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Quote:
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01-08-2020, 07:42 PM | #8 |
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Incandescent bulbs are just a coil of wire. A little heater coil that glows white-hot. They don't care which direction the current is flowing, they work either way round. They have a fairly high resistance - which is converted into heat as well as light.
Many old indicator circuits are designed around using bulbs; as these aren't polarity-sensitive at all, as soon as you provide current with a path to ground, it's "job done"... An LED is just a diode that happens to emit light (they actually generate small amount of electricity if you expose them to light as well, but usually not enough to be useful) The voltage the LED itself wants is determined by the doping of the substrate - and thus the colour they produce. White LEDs only work with 3V, red ones want 1.9V, UV ones 4.1V. They either have a current-limiting (aka "ballast") resistor built-in to the package to allow it to be directly connected to a 12V circuit, or sometimes multiple - eg 4 - LEDs are wired internally in series in the package. LEDs only allow current to flow in one direction. Even with the ballast resistor, they have a very low resistance to current flow in this direction - which is why they draw so little power. (A 2W bulb, at 12V, draws 160ma, and a 3W bulb 250ma. A typical white miniature LED uses 10ma - and probably brighter than a 10W bulb. It'll generate a little warmth in the ballast resistor - but still a lot less power overall than a bulb.) However, current flow in the other, "wrong", direction, with an LED has a very, very, high resistance - think of it as infinite. Much, much more resistance than a bulb. That's the "diode" part of "light emitting diode". With non-LED flasher relays and no load resistors, the relay hyper-flashes because the the forward resistance of the LED - even with the ballast resistor - is nothing compared to a bulb. So it behaves as though a bulb is out. If you resort to load resistors, you pretty much throw away the "low current draw" advantage of LEDs (the load resistor just turns the extra current into heat), but you do get to keep the "I don't blow bulbs", "they're brighter" and "they respond almost instantly" benefits. |
01-08-2020, 07:55 PM | #9 |
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Join Date: Jun 2010
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Ok .. for the sake of being able to respond promptly I'm going to say .. thanks very much for that and it seems to explain the situation.
I say "seems" to explain simply because I need to study it all a bit longer before I can say that I've fully grasped the whole picture. However, I'm now pretty much up to speed with the thing about the other side of the indicator circuit serving as an earth path for the warning light. Also the diode installation looks at first glance to make sense. Really, I just wanted to respond and say thanks without necessarily giving the impression that I fully understand the full picture just yet. Perhaps of interest, I did observe the timing of the illumination of the indicators compared to the warning light and found that they were in fact in phase on my bike as it currently stands, not out of phase as the first quote suggested they would be .. but I can't profess to currently have an understanding of why either should be the case. Also, I think I have determined that the original warning light bulb is (probably) 1.2W. I have found some which are rated at 2.3W and I might just try one of those (at under£4 for two, its money well wasted). I'm just curious to see (ie prove) what effect they might have. Finally , its unfortunate eh ?, that the quotes use the word "indicator" to describe the warning light .. thus creating an obvious potential for confusion with the turn signals (or indicators) themselves. Here's hoping that the author is better at electrics than they are at the use of language. Anyway, thanks muchly to everyone for your help. And please feel free to add further comments if you feel the need. Meanwhile, I'll ponder my next move. ps. The above was written prior to reading the last post .. #8 |
01-08-2020, 08:04 PM | #10 | |
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Quote:
I've always reasoned that if the system behaves as if a bulb is out, that would tally with an ultra high or infinite resistance, not the ultra low resistance of an LED. In other words, it would behave as if the bulb had been short circuited (low resistance path) rather than blown (infinite resistance path). |
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01-08-2020, 08:18 PM | #11 | |||
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Quote:
What voltage do you actually see on the lead for the tell-tale light? Maybe it's some interaction with the flasher relay - how many wires? Quote:
Quote:
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01-08-2020, 09:21 PM | #12 | ||
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Quote:
Heh. As-if... https://auto.howstuffworks.com/turn-...he%20resistor. Quote:
So the resistance from the bulbs in parallel is lower than two bulbs in series (parallel resistance is calculated as 1/Rt = 1/R1 + 1/R2 + 1/R3 + ...). A modern one will still operate with one bulb out - but if you've blown a 21W bulb, it'll hyperflash - because a single bulb means more resistance, so with less current flowing, bi-metallic strip doesn't get as hot - and cools down faster. LEDs draw so little current without load resistors that an electro-mechanical relay might not operate at all - but if it does, it hyperflashes, same as if you've got a bulb out. |
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01-08-2020, 09:25 PM | #13 |
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I couldn't tell you what voltage I see on the lead for the tell tale light cos my multimeter has gone intermittent after too many winters in a damp shed.
Flasher relay is three-wire. So then I checked my modified Dommie (Honda) which is fitted with monster indicators bearing LED bulbs, an aftermarket, LED-specific flasher unit (also 3-wire) and a Koso dash unit. Those flash out of phase with the warning light. So then I checked my car (I weakened and bought one last winter). Bog standard Citroen C1 (so just half a car, really). I was expecting out of phase but they flash in phase with the warning light. Good point about the heat in the 2.3W replacement bulbs ... I'll check. Then again, its an intermittent flash rather than a continuous illumination so maybe the odds are in my favour as the same bulbholders hold continuously lit warning lights for lights on, main beam etc. |
01-08-2020, 09:50 PM | #14 | |
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Quote:
I figured out the redundant side of the circuit creating the earth whilst out in the workshop, but I was kind of half way there in my post. Jeff I have some super bright green LEDs which need to work in sets of three and need 12V, you're welcome if they will work for you. Request to admin... Can we please make this sticky as it's such a good explanation?
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02-08-2020, 01:33 PM | #15 | |
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Quote:
Are the grounds good? Difficult to see how that'd be an issue with LEDs but not regular bulbs. But always good to check... I looked at a 1999 Monster current flow diagram; certainly looks to me like the repeater bulb is bridging the left/right indicator circuits (one terminal, F, is connected to the W/G (White/Green?) wire on the left direction indicator circuit, the other, E is connected to the W/BK (White/Black?) wire on the right direction indicator circuit. Which kind of raises the interesting questions
These question probably both have the same answer. Something is providing a path to ground... I suspect not a great path - hence the dim bulb. And you don't get both sides flashing at once. Although I'd have expected the LEDs to be more tolerant/work on lower voltage/current before the tell-tale bulb, so it's kind of a puzzle... You would be able to measure voltage between the indicator feed and ground anywhere in the circuit and see what the voltage is when you blag a DMM... If you've got a happy 12.5-14V on the indicator circuit, you're laughing, just a bad connection; trace it back through the harness to the bulb base until you see what's there. I doubt it's that simple though. It sounds like the flasher may be restricting the voltage and/or current available to the whole indicator circuit - and thus the tell-tale bulb - somehow. The LEDs are probably more tolerant of lower voltage and won't care, but a voltmeter would make it pretty obvious. If that's true, then a higher-wattage bulb likely won't make any difference. Perhaps the relay is in some way incorrect or faulty? LED flasher relays with a dedicated "pilot" (tell-tale) bulb lead exist, but you'd still need to re-wire the bulb and provide a traditional power/ground arrangement for it. In which case, seems to me you might as well fit a couple of diodes and be done with it. The "really easy" fix would be a T5 LED bulb that auto-sensed voltage polarity and Just Worked (TM) either way round. No wiring mods. Unfortunately, while these exist for things like the "festoon" bulbs I don't see any offered in a T5 package. Yet. (fun fact: in some older cars with two-positions for the interior light switch, current flows a different direction through the festoon bulb depending on whether the door is open or you switch the light on manually; use a "dumb" LED festoon and you get to choose which function works, depending on which way round you fit it...) I think I'd be leaning towards the dual-diode mod, providing a real ground and fitting a T5 LED. The LED should be much brighter than the bulb anyway. Win-win Should be able to de-pin the connectors somewhere convenient, re-arrange what you need in a little extra mini-harness and re-connect back into the original connector, so no cutting factory wiring. lol - Mate of mine had a Peugeot he never managed to get running. Kind of ironic, as he was earning a living as a mechanic at the time... He told me to never trust French electrics, and I believed him... |
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