Got my new bike light... pretty disappointed...

General Discussion about electric bicycles.
crea2k   10 kW

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Re: Got my new bike light... pretty disappointed...

Post by crea2k » Jan 09 2015 10:15am

speedmd wrote:
got a 555 timer chip on it that jumps it to the next output circuit each time the button is pressed
Wonder if you can bypass / jumper the circuit settings that are not needed, to give just a hi/ low. Off can be done up stream.
Possibly, when you but a flashlight driver you literally just cut or solder the traces depending on what functions you want.

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Re: Got my new bike light... pretty disappointed...

Post by NeilP » Jan 09 2015 10:39am

crea2k wrote:[
Possibly, when you but a flashlight driver you literally just cut or solder the traces depending on what functions you want.
but that all depends on the firmware the chip has ben programmed with
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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 09 2015 10:52am

I'm sticking leds to mirrors and getting a nice pattern. Good clean cut-off and what went up now goes down. It's not going to be improved upon by tir's or anything else fancy. It's just what the doctor ordered. Ultimately, a bit of mirror from a disco ball might be all a lot of these lights need to make them right.
Clever solution. The flat led XL-M emitters have a focusing lens built/molded right on them. They seem to be focused :P on high bay lighting apps. With all the transport applications, I would be surprised if they did not have some road specific (low/ wide/ half circle) focus lens chips that are available or maybe in the works. If not, a high temp injection molded / plated reflector would do it. Any optics folks out in the group?

Looking up high end chips, I found a 77 volt capable chip, the larger cxa. http://www.cree.com/LED-Components-and- ... -pages/CXA The cxa2590 looks like it will run right off a 18s pack. 10,000 + lumens :shock:

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Re: Got my new bike light... pretty disappointed...

Post by Gregory » Jan 09 2015 6:54pm

crea2k wrote:At a guess its just got a 555 timer chip on it that jumps it to the next output circuit each time the button is pressed.

Many of the cheap multi mode LED drivers I have use an attiny microcontroller. You can find several custom firmware like Dr Jones on the BLF (Budget Light Forum) for some boards, or some have a solder bridge across "stars" to select modes, or best option is just do like NeilP and buy a one mode driver.


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Re: Got my new bike light... pretty disappointed...

Post by biohazardman » Jan 11 2015 6:45am

For 25-30MPH I am happy with the 3-5 T6 XM-L units and think they are fine for my use but if you don't then buy 2 they are cheap. A piece of plastic, I used some thin carbon fiber cuz I had it, made into a visor with some aluminum foil glued underneath will point the light that goes into the trees back on the ground in front of you where you need it and not so much in the oncoming traffics eyes. Easy mod that made a big difference for me.
Some build the LED drivers to be easily modded others sand the numbers off of the chips so you don't know what they are. Such a wonderful thing to do to your customers with enough brains to mod things. I used to think that two of these single LED lights were bliss but now more is better.


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Re: Got my new bike light... pretty disappointed...

Post by friendly1uk » Jan 11 2015 8:52am

They look alright. What are they. Do you have a link?

I'm looking for a light that will take 50v and has perhaps a 45 degree beam/viewing angle. Few modes as possible. Must be a single led.

I have seen a fair few on the bay, but divergence is never stated and output is exaggerated. I can't make an informed decision.
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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 11 2015 11:00am

The XM-L chips they are using in most of these low cost lights is listed at 125 degree viewing angle. http://www.cree.com/LED-Components-and- ... /XLamp-XML Data sheet shows better than 80% luminance at +/- 45 degrees file:///Users/admin/Downloads/XLampXML%20(1).pdf Reflectors will change things quite a bit.

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Re: Got my new bike light... pretty disappointed...

Post by NeilP » Jan 11 2015 12:42pm

friendly1uk wrote:[

I'm sticking leds to mirrors and getting a nice pattern. Good clean cut-off and what went up now goes down. It's not going to be improved upon by tir's or anything else fancy. It's just what the doctor ordered. Ultimately, a bit of mirror from a disco ball might be all a lot of these lights need to make them right.

Thanks for the meanwell links.
Sticking them to glass..umm must loose the heat sink ability. You won't be getting a lot of thermal transfer through the glass.
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Re: Got my new bike light... pretty disappointed...

Post by NeilP » Jan 11 2015 12:44pm

If you want to reduce the viewing angle, then yu can de dome the LED. Remove the plastic / gel bubble over the LED and it gives a tighter point of light and reduced viewing angle
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Re: Got my new bike light... pretty disappointed...

Post by friendly1uk » Jan 13 2015 9:17pm

NeilP wrote:
friendly1uk wrote:[

I'm sticking leds to mirrors and getting a nice pattern. Good clean cut-off and what went up now goes down. It's not going to be improved upon by tir's or anything else fancy. It's just what the doctor ordered. Ultimately, a bit of mirror from a disco ball might be all a lot of these lights need to make them right.

Thanks for the meanwell links.
Sticking them to glass..umm must loose the heat sink ability. You won't be getting a lot of thermal transfer through the glass.
I was just giving you the idea. I'm actually using plastic mirror ahead of them on the same plane. I'm still experimenting, but ready for trials. Using glass mirror and higher powered leds. I won't be putting the reflector beside them though. I only need mirror where the beam needs modifying. Which is ahead of the led in free space.

I got 50 ultrabrights in a bid to spread the heat and voltage around. Using nice workable plastic safety mirror for modelling. The ultrabrights are simply not though. So I'm moving to a single source of light. Which can create a problem with laying the reflected light over the directly lit area. Producing a banding effect. Because the mirror can't get dead center of the led. I may yet move to an alloy reflector. I can get a bit from a fluorescent fitting. The mirrors width is a problem. A 5mm led means the mirror is 2.5mm off axis. That seems ok. The mirrors 4mm width moves the reflective surface even further off axis, and it's during this 4mm I see undesirable effects and the mirrors size requirement grows considerably.

Mirror does do a great job the eye can really appreciate. The alloy just isn't going to shape up. I might need to silver some glass. It's work in progress still.
bmsbattery sent me broken and incorrect stuff, and won't even talk to me about it.

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Re: Got my new bike light... pretty disappointed...

Post by amberwolf » Jan 13 2015 10:11pm

Use front surface mirrors; you can get them out of old copiers and laser printers in the scanner assembly, and from some old scanners too.

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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 14 2015 9:08am

On the reflectors, heat should be little concern on these sub 10 watt led chips. First surface Plated plastic flash light stuff should be perfect at this power level. The chips molded on lens look to be molded in a super hard silicone (plastic/rubber) material that is a type of high temp / high hardness plastic that is normally used to coat eyeglass lenses. They claim very high efficiency with it. Would not want to mess with the surface finish as it would impart some serious loss in efficiency if you can not polish it back to spec.

The CXA chips look very interesting. http://www.ebay.com/itm/221453210586?_t ... EBIDX%3AIT You should be able to run them right off a 36 volt pack setup. Imagine you would need to limit current some way to 0.3 amps via a simple circuit /supply. Look to be very efficient.

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Re: Got my new bike light... pretty disappointed...

Post by friendly1uk » Jan 14 2015 1:27pm

Thanks Chaps. Big thumbs up for your help with both mirrors and opening my eyes to how cheap good emitters are.

I have had 5mm leds with flat front before. They never gave a nice light distribution though. The divergence was usable but the light was not spread evenly. Like a flashlight of old.

I have a 5w single led unit with wide input range I can play with. The beam is a little narrow though. I want something right before I spend time on it.

I hope you will find this picture... illuminating?
It's a keyring like torch. I can't make a perfect D as I can't get on axis without introducing defects into the pattern near the horizon. You can see a bit of this where we transition from illuminated to shadow. It is more D shaped than my phone makes it look though. Honestly, It's a D not a circle. Maybe I shouldn't post, I'm making it look a lot worse than it is
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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 15 2015 1:21pm

Found a low cost 48v dc in driver. http://www.ebay.com/itm/121478459634?_t ... EBIDX%3AIT Should power two or three cxa chips. 8)

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Re: Got my new bike light... pretty disappointed...

Post by NeilP » Jan 15 2015 1:26pm

speeded wrote:On the reflectors, heat should be little concern on these sub 10 watt led chips. .
Not so sure. Cooked a XM L2 the other day running a single 18650 cell at 2.5 amps with no heat sink. Just over heated and burnt out after about ...5 minutes? maybe less It was on a bare 10mm MCPCB star
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speedmd   100 MW

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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 15 2015 3:22pm

The chips need to be anchored down with thermal paste to a heat sink for certain or they will burn out if you put the juice to them. They run hot. The reflectors separated by a tiny air gap if using anything other than high temp plastic. Glass/metal is best if up tight and pushing near the current limit!

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Re: Got my new bike light... pretty disappointed...

Post by NeilP » Jan 15 2015 3:35pm

Exactly, they need a heat sink thst is my point, but your bit that I quoted, as I understood what you were saying was that just the pladtic or glass reflector was wnough.

Even if youu use thermal paste to stick an LED star to a plastic reglector or a glass mirror, to my mind that is as good as no heat sink. Maybe thete are some types of glass or plastic that are good thermal conductors? but I bet none as good as a block or plate of copper or orher metal.
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Re: Got my new bike light... pretty disappointed...

Post by Alan B » Jan 15 2015 6:12pm

crea2k wrote:If you want something nice and bright though try this : http://www.fenixtorch.co.uk/Shop/Fenix- ... Light.html
I know from my candlepower forum days that Fenix make bad ass lights, iv got a TK 70 and its brighter than my car.
I use the Fenix BT20 and it is decent for ebike use at bike speeds. It is one of the few lights that has somewhat appropriate beam shaping for bicycle use. At least they tried, which almost none of the other manufacturers have bothered to do.

If you are running at motorcycle speeds then real DOT/SAE motorcycle lights are your best choice.

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Re: Got my new bike light... pretty disappointed...

Post by friendly1uk » Jan 15 2015 10:01pm

I opened up an ebay 5w and measured 65c after a while. It has a plastic reflector but they keep it away from the emitter. I can see it reaching 80c at the most. Certainly if I start making something from scratch I could melt acrylic. I want to modify an existing torch though really. So heat should already be taken care of.
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I took almost identical photo's with and without mirror. Unfortunately everything moved a bit. You can see one gives a circle and one has been modified enough to now give glare. Same beam width. Brighter floor and distance. Signs that little is going up.
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My ebay lights accept my 54.6v having 12-80v input range. They could be a usable driver, as the beam is like a light-sabre. At 5 meters the spot is about as wide as my handlebars. The beam center reaches out about 100 meters and paints a 3 meter wide circle.

Maybe my highly focused light needs a lens like this one, not just a mirror
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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 15 2015 10:29pm

These 10w chips need cooling / heat-sink if you want to run them at the higher range of their specs. Some off of ebay below. Thermal grease between the chips and them will help also. Polished metal foil is your best bet for reflectors if your not able to cool them down enough if sealed up to keep water out. Some plastics will take the heat such as polyimide or peek and lots of ready made ones also listed on ebay that are cheap enough to play around with a bunch of ideas. A interesting time in lighting. Image Image

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Re: Got my new bike light... pretty disappointed...

Post by friendly1uk » Jan 16 2015 7:25am

I have my eye on a dental mirror. It's the right mirror, of the right proportions, but it's main selling point is it's in a holder.

I'm going to be waiting a while to find a light with the right kind of beam to modify. I think I would rather be seen blinding people than make something from scratch though. I know it would be right if I did it, but I really think somebody must be making something with the right divergence angle. Something like the xm-l chips must be in use somewhere without optics.
bmsbattery sent me broken and incorrect stuff, and won't even talk to me about it.

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speedmd   100 MW

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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 16 2015 9:30am

The raw xm-l should give a reasonably wide pattern. You could angle a bunch of separate stripe type to give you the pattern you wish also. Something like the 3w bars are interesting and look like they would run cool enough to slip into a clear plastic tube and mount nicely to bike / tubes.
Image

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Re: Got my new bike light... pretty disappointed...

Post by Alan B » Jan 16 2015 9:42am

Raw LED patterns are much too wide, look at the datasheets. Compare that to the DOT/SAE patterns required for automotive lights.

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Re: Got my new bike light... pretty disappointed...

Post by ebike » Jan 16 2015 2:34pm

madnomad wrote:So my new bike light arrived today, and its pretty disappointing:
http://www.ebay.co.uk/itm/191304896814? ... EBIDX%3AIT
It has an extremely focused beam,.....
Tip/hack for the U2 LED Light:

Open the front cover of the lamp
and turn the "crystal" upside down.
(...and totaly remove the round metalic part and the round rubber ,if there is any)

Now close the lamp, you may not be able to close the front cover totaly now,
but that is fine (dont force it!! or you may break something),
you can use some transparent tape to reinforce the closing gap.

Now you have a cool wide angle beam!!

.

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speedmd   100 MW

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Re: Got my new bike light... pretty disappointed...

Post by speedmd » Jan 16 2015 3:28pm

Ebay lists all sorts of reflectors/ angles for the xm-l and many other style chips. Agree, the stock xm-l lens is a bit too wide for road use as is if you point it down the road. Great for the woods. Foil tape and a properly formed 3d printed reflector shape and you should cure / be able to tame them quite well. Other chip I find very interesting looking and significant power output are also 120 degree, the smd 25W. They also would need some custom reflector work to make road worthy. http://www.ebay.com/itm/121362080413?_t ... EBIDX%3AIT

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