July 28, 20205 yr This output from the controller is very useful. I don't use it for driving lights, but for powering a very loud horn and also as a feed for my voltmeter. These horns are cheap, but loud enough to get you taken seriously by cars and run up to 60V. 12V versions are available, but they use far higher current.
July 28, 20205 yr I'd be interested to read that article but from the way you describe the action of that device, it sounds like a switched mode power supply aka buck converter. These devices don't 'waste' voltage, they alter the voltage. The buck converter will in itself use some level of power - whether that is less or more than a simple dropping resistor requires some bench testing. And of course using a buck converter takes you into the realms of finding a location for it and any connectors, containers, waterproofing etc but does offer a more stable voltage for the lights as the bike battery discahrges say from 42v to 30v. As a very rough estimate, if the dropping resistor is sized to 'drop 5/6th of the battery terminal voltage, then the voltage available to the light will vary from 1/6th of 42v to 1/6th of 30v which is 7v and 5v respectively,which for LED lights may not even be noticeable. As a retired electronics person, I favour the more 'correct' buck converter approach, but the practical man in me is edging towards the dropping resistor(almost O NO) . I can fully understand why some folks just opt for clip-on lighting. More stealable but no additional cables and independant of the ebike battery (thinking flat battery scenario here). The little beastly below at around £4 uk pricing, could likely be found a home inside some light fittings. [ATTACH=full]37291[/ATTACH] No need for one as the lights for wiring already have an integrated one inside hence the 6v - 60v usage range. Just noticed vfr also mentioned this in #24, I hadn't read his reply until I browsed the rest if the thread.
July 28, 20205 yr This output from the controller is very useful. I don't use it for driving lights, but for powering a very loud horn and also as a feed for my voltmeter. These horns are cheap, but loud enough to get you taken seriously by cars and run up to 60V. 12V versions are available, but they use far higher current. [ATTACH type=full" alt="37292]37292[/ATTACH] I'm sure I came across a front led up to 60v with horn and switch on my net meanderings.
July 28, 20205 yr I don't need internet calculators, like you because I understand how it works, so I can do it in my head. They used to call it mental arithmetic. Of course you can only do that if you have the understanding and the mental capacity to multiply by 6. That's right. the resistor will be fine when it dries out; however, your expensive light won't fare so well when it gets the entire battery voltage across it - should make a nice pop and maybe a bit of fizz too. BTW, you control LEDs by current, not by voltage. That's why you need driver circuits for them. You apparently do not understand how high wattage ceramic resistors work either. They are sealed, and can be safely used in many environments! Another negative! Thats like saying that a ceramic tea cup would leak tea!!! A standard carbon resistor might be affected, but not a metal or ceramic....Some heating elements for small heaters, can even be built with such resistors.....though I haven't seen that in the last 40 years myself! Here are images of resistors that are sealed and totally unaffected by a drop or two of water.....just as I said.
July 28, 20205 yr I'm sure I came across a front led up to 60v with horn and switch on my net meanderings. I have a STVZO one off AliExpress with the integrated horn, they need a Wuxing handlebar switch to operate for on/off and horn. The ones without horn don't need the handlebar switch as they have one on the rear of the light.
July 28, 20205 yr I have a STVZO one off AliExpress with the integrated horn, they need a Wuxing handlebar switch to operate for on/off and horn. The ones without horn don't need the handlebar switch as they have one on the rear of the light. Yes, forgot to mention I use a Wuxing handlebar switch for the horn. I've got one with the horn on its own and another with an integrated light switch.
July 28, 20205 yr Yes, forgot to mention I use a Wuxing handlebar switch for the horn. I've got one with the horn on its own and another with an integrated light switch. The light output form the 100lux models are very good and for town night riding is superb.
July 28, 20205 yr You apparently do not understand how high wattage ceramic resistors work either. They are sealed, and can be safely used in many environments! Another negative! Thats like saying that a ceramic tea cup would leak tea!!! A standard carbon resistor might be affected, but not a metal or ceramic....Some heating elements for small heaters, can even be built with such resistors.....though I haven't seen that in the last 40 years myself! Here are images of resistors that are sealed and totally unaffected by a drop or two of water.....just as I said. I think what vfr was getting at is that when it gets wet, if the leads are not well insulated you could get a conducting path along the outside of the resistor. However, my biggest concern is the amount of heat generated in a small space. It must get quite hot and I wouldn't like to touch it, or brush against it by accident. Dropping resistors are ok for small indicator LEDs, but for high power lighting LEDs it's not a great solution, when 6 to 60V input bike lights are so readily available at low cost. BTW Andy, do you think you could find a way of posting that is not so confrontational? Everyone has their own views and opinions, but for a forum to work properly, people need to express their opinions in a way that is not aggressive, confrontational or trying to score points off of others. We want to encourage as many people as possible to get into e-bikes and if they go on a forum where people are tearing chunks out of each other, it is completely counter productive. Many people (especially women) will be put off posting if they see this kind of behaviour for fear that their posts will be torn apart by others. There are ways of stating your points without upsetting others. I don't always get it right, but I do my best to try to accommodate the views of others and agree to disagree, rather than cause a pointless escalation.
July 28, 20205 yr Andy's is like Cloughie, where both parties sit down and dsicuss something then at the end he decides he is right any way. No matter what others say. Most on the forum post out of experience /knowledge but Andy tends I think to read a lot of nonsense on the web then cuts and pastes links on here for which I have no time for.
July 28, 20205 yr Andy's is like Cloughie, where both parties sit down and dsicuss something then at the end he decides he is right any way. No matter what others say. Most on the forum post out of experience /knowledge but Andy tends I think to read a lot of nonsense on the web then cuts and pastes links on here for which I have no time for. I reckon its not hard to get the measure of posters when joining a new forum, who knows what, who to pay attention to, who to take with a pinch of salt.
July 28, 20205 yr I reckon its not hard to get the measure of posters when joining a new forum, who knows what, who to pay attention to, who to take with a pinch of salt. Some times a pinch of salt is know where near enough. Edited July 28, 20205 yr by Nealh
July 28, 20205 yr Some times a pinch if salt is know where near enough. There's a whole spectrum of possibilities.
July 30, 20205 yr Some times a pinch of salt is know where near enough. A pinch of salt around a tequila glass maybe!
July 30, 20205 yr Author I reckon its not hard to get the measure of posters when joining a new forum, who knows what, who to pay attention to, who to take with a pinch of salt. True enough - I've not been on this forum long and already I am able to sort the wheat from the chaff (or maybe the salt from the vinegar?). Anyway, back to the original posting - obviously most just use the 'light output' from the controller for ...... lighting:D. So guess what, I think I'll follow the wise and do the same. AliExpress seems the most likely source (and I've scoured the site a number of times - but you get crossed eyes after a while) but I am a little cautious about which choice of light to go for in that I know that many of the cheap Cree LED lights have a very untidy beam pattern that can be disconcerning/annoying for other road users (and I know this is less of an issue for off-road use). So if anyone can either give a recommendation or pointer (with links please) to a front light with a decent beam pattern, I'd be very grateful (and I'll not be going for the Busch and Muller type either - I'm a pensioner after all ). Getting a decent front light is the first goal and then a good rear red light that will fit snugly on the pannier rack also. Thanks in advance
July 30, 20205 yr True enough - I've not been on this forum long and already I am able to sort the wheat from the chaff (or maybe the salt from the vinegar?). Anyway, back to the original posting - obviously most just use the 'light output' from the controller for ...... lighting:D. So guess what, I think I'll follow the wise and do the same. AliExpress seems the most likely source (and I've scoured the site a number of times - but you get crossed eyes after a while) but I am a little cautious about which choice of light to go for in that I know that many of the cheap Cree LED lights have a very untidy beam pattern that can be disconcerning/annoying for other road users (and I know this is less of an issue for off-road use). So if anyone can either give a recommendation or pointer (with links please) to a front light with a decent beam pattern, I'd be very grateful (and I'll not be going for the Busch and Muller type either - I'm a pensioner after all ). Getting a decent front light is the first goal and then a good rear red light that will fit snugly on the pannier rack also. Thanks in advance Take the advertised number of Lumens with a big pinch of salt. You will see ludicrous numbers given for a lot of lights you can buy. A typical 5W Cree can give max about 700 lumens, yet you will see claims of thousands of lumens for a lamp with that LED. Then you will see lamps made of clusters of many 5W Cree LEDs and claims of tens of thousands of lumens. When you think about the amount of heat generated in that small space, there's no way those LEDs would even give their rated intensity. Have a look for LED lamps with Cree XHP70. These are single LEDs capable of 4,000 lumens and they are higher voltage than standard LEDs. I saw some good lamps when I was looking late last year with these LEDs, but the sale didn't go through. The technology is changing so fast now, I expect people will correct me with even better examples...
July 30, 20205 yr True enough - I've not been on this forum long and already I am able to sort the wheat from the chaff (or maybe the salt from the vinegar?). Anyway, back to the original posting - obviously most just use the 'light output' from the controller for ...... lighting:D. So guess what, I think I'll follow the wise and do the same. AliExpress seems the most likely source (and I've scoured the site a number of times - but you get crossed eyes after a while) but I am a little cautious about which choice of light to go for in that I know that many of the cheap Cree LED lights have a very untidy beam pattern that can be disconcerning/annoying for other road users (and I know this is less of an issue for off-road use). So if anyone can either give a recommendation or pointer (with links please) to a front light with a decent beam pattern, I'd be very grateful (and I'll not be going for the Busch and Muller type either - I'm a pensioner after all ). Getting a decent front light is the first goal and then a good rear red light that will fit snugly on the pannier rack also. Thanks in advance Avoid the ones with a thick lens on the front. They're more like spotlights with a very narrow beam. The silver ones with several LEDs are not bad.
July 30, 20205 yr Avoid the ones with a thick lens on the front. They're more like spotlights with a very narrow beam. The silver ones with several LEDs are not bad. The lamps with two or three Cree LEDs with a good heatsink are ok, but this sort of thing drives me up the wall: How can 15x about 700 or so ever get to 52,000? Then if each of those LEDs is 5W, the heat output must be around 60W. That heat has to go somewhere, and it's not like there is a big heatsink of the sort you would see on a computer CPU.
July 30, 20205 yr Then if each of those LEDs is 5W, the heat output must be around 60W. LEDs are around 50% efficient, so only 30w goes as heat. Still a lot. I had thought it was over 80% efficiency but just looked it up and my memory had (as so often) served me wrong.
July 30, 20205 yr LEDs are around 50% efficient, so only 30w goes as heat. Still a lot. I had thought it was over 80% efficiency but just looked it up and my memory had (as so often) served me wrong. I had it in mind they were about 20% efficient, but that was a few years back and the technology is improving so fast! My brain is too old and tired to dig out the equations to convert Lumens to Watts out, but I noticed from the data sheet, even to get just under 700 Lumens for a T6, you have to drive each LED with at least 2 amps at more than 3V, so more than 6 Watts (>3x15, or >45 Watts of heat) and to go higher (say 1000 lumens), to get absolute max ratings, 3 Amps at 3.35V, so about 10 Watts. So even if 50% efficient at max drive (giving 15,000 lumens), you'd be dissipating 15 x 5, ie, 75Watts, with no real heatsink other than the case. https://www.cree.com/led-components/media/documents/XLampXML.pdf
July 30, 20205 yr The lamps with two or three Cree LEDs with a good heatsink are ok, but this sort of thing drives me up the wall: [ATTACH type=full" alt="37336]37336[/ATTACH] How can 15x about 700 or so ever get to 52,000? Then if each of those LEDs is 5W, the heat output must be around 60W. That heat has to go somewhere, and it's not like there is a big heatsink of the sort you would see on a computer CPU. It doesn't really matter what they're claiming. One thing is sure: 15x CREE XM-L U2 will be bloody bright, when 1x CREE XM-L U2 is enough to fully light unlit off-road tracks.
July 30, 20205 yr Author Avoid the ones with a thick lens on the front. They're more like spotlights with a very narrow beam. ......................... When the cheap Chinese CREE lights first started to become popular on UK roads, they were often criticised for the glare they caused to on-coming road users (including cyclists of course). So when I bought one I also bought a Fresnel Lens which gave it a nice horizontal cut-off similar to what you see from dipped car headlights. This leans me towards my choice of new light having a similar lens arrangement to again avoid presenting glare to other road users. I take your point entirely about ending up with a 'spot light/(too) narrow a beam' though and 'too narrow/wide enough' is going to be subjective as well. What fun!
July 30, 20205 yr I take your point entirely about ending up with a 'spot light/(too) narrow a beam' though and 'too narrow/wide enough' is going to be subjective as well. What fun! Trust me, they're too narrow to be any use on a bicycle. I bought one, so I know.
July 30, 20205 yr Author Thanks [mention=4809]vfr400[/mention] - I will heed your advice. What this thread needs is recommendations and pointers to lights that are a fair price, don't blind oncoming road users but give a useful beam for unlight road riding - anyone?
July 30, 20205 yr It doesn't really matter what they're claiming. One thing is sure: 15x CREE XM-L U2 will be bloody bright, when 1x CREE XM-L U2 is enough to fully light unlit off-road tracks. Yes it will! Not sure how long it will last though, due to overheating...or it may have to be down rated so much for current that it's not really any better than a smaller number of LEDs run at a higher current. The lamp was sold to run from a small 8.4 Li-ion pack, so if it draws the full potential 150W of power of 15 LEDs it would run out quite quickly. That level also is getting to the point where it would have a significant impact on your battery pack if you run it from the e-bike battery. This lamp was for 15x XML T6 LEDs (I haven't looked up how that compares to the U2). On my bike I have a single XML T6 run from a 5V USB charger pack at about 1 amp and that does the job. If I went off road, maybe having a few of them would be good, perhaps at different angles to cover close and far fields. I have a handle bar extension ahead of the main handlebars, so I can get extra voltmeters, speedo, lamps and horn etc, etc Edited July 30, 20205 yr by WheezyRider
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