Very Bright Very Cheap Light runs from battery

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tillson

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May 29, 2008
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My question was in relation to the OP and had not strayed from the thread. Still none the wiser thou:confused:

Do you know what Voltage the original lamp on your bike runs at? I think this cheapo light will function on anything between 12 and 80 volts. If your lighting supply fits into this band you next need to consider how much current it will draw and if your lighting circuit is up to it. The current will be dependant on the voltage, so its not possible to give you an answer without knowing a few more details.
 

jazper53

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Jan 20, 2012
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Ok thx, will check the front light to see if any details, if none will check the voltage.
 

jazper53

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Have checked voltage on wiring to light on the meter and is showing 40v exactly the same as the batteries output.
 
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Deleted member 4366

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Current will be minimal then, so it should connect directly.That just leaves one potential problem depending on how it's switched. If you have a switch directly on that 40v line then no problem. If it's switched indirectly via a transistor in the controller, it'll now be drawing three times the current. It'll probably be alright, but we don't know the rating of the transistor.
 

jazper53

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Could that transistor be built into the back of the light assembly as there seems to be a circuit board with three colour coded resistors built in
 
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Deleted member 4366

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That's the driver for the LED. You have to follow the light wire. Does it go to the switch or the controller?
 

jazper53

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It does look like the wiring to the switch goes to the controller as does the wiring to the light
 
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Deleted member 4366

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It'll probably still be OK. Worse case, the transistor will blow and leave the light permanently on or off.
 

drsolly

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Jan 21, 2014
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I like the red gel idea. I've ordered one of these lights, as a possible rear lamp.

Yes, I know it's too bright for a rear lamp. But when I'm cycling in town at night, I want car drivers to be *very* aware that a bicycle is in front of them.
 

tillson

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I like the red gel idea. I've ordered one of these lights, as a possible rear lamp.

Yes, I know it's too bright for a rear lamp. But when I'm cycling in town at night, I want car drivers to be *very* aware that a bicycle is in front of them.

I wonder if it will be too bright for a rear light? The red gel will filter out all but the red light from the spectrum, so what is actually emitted will only be part of the LED output. This may be enough for many users.

The £50 light that I linked to has a red LED fitted, it actually looks clear when switched off and not at all like a rear light. When switched on, only red light is emitted from the LED so you get all of the output (and there is a lot) in the form of pure red light.

Fifty quid is a lot for a rear light though. If you want to try a cheaper version you might be able to make something using one of these

http://www.dx.com/p/3156-3w-200lm-1-led-red-light-car-steering-light-12v-194702#.U1u4Bye9KSM

Search red LED on Deal Extreme there are many possibilities.

Deal Extreme also sell red LED emitters which you can build into a small aluminium torch casing (which they also sell) and you can have a rear light bright enough to start a fight for under £15.

I think red emitters are better way to proceed than filters.

(Sorry if this is deviating from the original thread again, but it is sort of related.)
 
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drsolly

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Jan 21, 2014
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Nice idea. I just ordered a 3w led from Ebay. I chose 620 nm rather than 660; I think 660 would be too dark-red. £1.59. It wants 2-2.5 volts, 700 ma (which I think is 1.5w, not 3w). If it works, I'll use it with a stepdown converter (£0.99) for a seriously bright rear light for under £3.
 
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Do a search on Ebay for "2 laser flahing rear light".

Forget about the lasers, but the light itself is more than you'll ever need for about £2.
 

drsolly

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The worst accident I ever had ... I was on a motorbike, stationary, at a roundabout, waiting for a gap in the traffic big enough for me to get onto the roundabout. I saw a gap, but I decided it wasn't big enough, so waited more ... but the car behind me decided that it was big enough, forgot that I was stationary in front of him, drove into my rear, sending me out into the middle of the road of the roundabout, and I was lucky not to get run over.

That's why I'm keen on getting respect from traffic behind me.

I've ordered a ridiculously bright 3w red led emitter, I'm hoping I can work out how to make it shine, using the bike battery. I think I just need to put it in series with an appropriate resistor. I don't even need a switch; it'll either be plugged into the battery or it won't.

Then I started thinking about how to make it flash. Circuitry required? Or ... one of these.

http://www.ebay.co.uk/itm/DC-100V-NC-NO-Door-Window-Contact-Magnetic-Reed-Switch-Alarm-Distance-10-20mm-/181210761056?&_trksid=p2056016.l4276

Put the magnet on a wheel, so while I'm stationary it's a steady light, while I'm moving, it flashes.

And then I thought, hmm. Even simpler. Run the 3w LED as a steady light, and have a flashing red led next to it.

I'm hoping that the flashing will make it impossible to ignore, the two lasers will mark out a region that car drivers won't want to encroach on, and the 3w led will be bright enough so that car drivers won't want to get close.
 

drsolly

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Jan 21, 2014
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The light arrived, Astigmatic. Wow, it's bright!
 

Alchemist

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Mar 21, 2014
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Managed to set up my light of the recommendation in this thread, but have to say I'll be sticking to the (admittedly considerably dearer, at £24) 3x Cree XML T6 : http://www.ebay.com/itm/4000-lumens-3X-CREE-XM-L-T6-LED-Bicycle-Bike-Head-Front-Light-Headlamp-Headlight-/281236044472?pt=LH_DefaultDomain_0&hash=item417af97ab8 , which I have found to be considerably brighter and sharper even on the first setting (ie one led lit up out of the three). The cheaper Banggood one is okay, for sure, and probably all that is required in a built up area, but the difference between the two of them is clear to see ;)
BTW, I was running off a charged 36v 17Ah battery for the thread light (Banggood), but using a small 4 cell battery pack (8.4v 6400 mAh rechargeable) which comes with the Cree model.

Sorry if this is not what we are looking to hear, but this is my 'con' with this particular light. On the other hand the Banggood is 1/4 the price, which must weigh very much in favour of it; as it is, I live in an area devoid of public lighting, and so for my circumstances I would definitely favour the Ebay one above. IIRC I bought this on the recommendation of a North American light collector on Youtube, who was (rightly) very complimentary about this light, especially when compared with much more expensive models. I think there's a vid of this light in action/being tested somewhere. Here is a vid by a UK tester, not the same price ( they're not as dear as £30), but the same light and what you get:

Having said all this, I am sure the Banggood light would be absolutely fine for urban use, and if anyone is looking for a new unused one I have 3 still boxed up and ready to post here, and one with a switch already fitted, which I'd also be happy to let go to a good home.

Cheers,

Alchemist
 
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