What's inside a cheap bike light and what can be done to make it better... (Pic Heavy!)

Back in October last year I decided that I really needed some better lights on the ChimpCycle. I’m a daily user of a fantastic cycle trail which is completely unlit and with trees running down either side. Despite being through an urban area it’s completely dark over much of its length. Having looked at the market and also my bank balance I took the plunge and ordered a MagicShine clone from a UK eBay vendor for £24inc shipping. A few days later this arrived:

It’s a 3 modes unit with the standard 2s2p 18650 pack and charger. Modes are presently H~~L~~>Strobe. I’ve run it for a few months of commuting with a wide angle lens. I recently took delivery of a second even cheaper unit which is better made and brighter. This has prompted me to pluck up the courage to take this unit to bits and look on it as a platform for modification. With that in mind I wanted to have a look and see what might make it into a better light. I’ll define better at the end of the post.

Right, lets have a look inside. Remove the bezel and the lens and reflector pop straight out:

The reflector is smooth and made out of alloy. It certainly has some mass to it. Having removed the front we can now see the emitter and front of the pill:

The pill is held in place with a lock ring, here it is on top of the body:

The pill unit then just slides out, although it did take a bit of wiggling of the wires:

Here’s a close-up of the whole pill assembly:

The star is attached to the alloy pill body with thermal gunk. The wires then feed through this into the central section which is hollow. At the back in a brass ring is the actual driver, this is mounted with thermal paste into the brass ring and press fitted into the pill body:

And with the driver removed:

I’ve only managed to measure the current on full power, it drew 1.86A measured direct off the wires on the star, strangely I was seeing stars for a couple of hours after my Heath Robinson shield moved whilst testing.

So, that’s the light as it stands. What I’m interested in doing is using this light just for throw to light up the trails well ahead, floody throw would be great. I use my other light with the wide lens and am happy with that for near flood. In use the body of this unit does not get warn, even after an hour of use on high. This might just be the bad pill to body interface but I think it would be more than capable of handling higher temps. As this is a throw light it’s never really likely to see more than a couple of half hour sessions between charging opportunities on the bike. I can get some brass milled to add mass to the pill easily enough.

I could really use some suggestions on ways to go with this. I’m sure I could get a lot more out of it for replacing the driver with something that could push 2.4A - 2.8A, all be it at the cost of run time. I would have use for lower power modes including something nice and low but strobe is not wanted. I’ve looked at the bFlex type options but the drivers cost 1.5x the cost of this whole light. I’d consider doing the emitter at the same time if I could keep the costs reasonable but think the XML is probably quite a good base for a floody throw.

Reserved.

1.86A draw from 2s2p means its a buck driver and already supplies more than that to the led. Break the connection from the driver to the led and measure current there. To get better throw, a different emitter or reflector or both. If you use a different emitter you might need to change the drive current. If your looking to save £’s check into locating the sense resistor on your driver and changing that value but decide on your reflector/emitter combo first. 7135 based drivers work on 1sxp only so you would need a buck driver if you changed that. If you go to multi emitters then you would need a boost driver instead. Have you checked over on mtbr? Lots of good stuff there.

I de-domed one of these ( the headlamp version) the other day (Wednesday?) for a friend. They de-dome very well: quite a good gain in throw with very little reduction in hotspot size (not as much spill though). I will put before and after wall-shots up if you want?

not much to offer in terms of improving light output (other than a better thermal path from pill to housing), but I would suggest doing something to support that coil on the driver. Having one or both of its legs break off from vibration appears fairly common, so some potting compound or hot glue would help.

There’s not a whole lot of point doing much to these lights as they’re so cheap. I just struggle to understand how they can still make a profit on them at that price, as they clearly don’t fall to pieces the moment you use them.

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…i would be very interested in a link to the `cheaper brighter` light you bought…

I’ll warn you now, mine did take nearly 6 weeks to arrive, but for the price I can’t complain:

http://www.ebay.co.uk/itm/300645609770?ssPageName=STRK:MEWNX:IT&\_trksid=p3984.m1439.l2649

H>M>L with Hidden strobe if you press and hold in low. I’ve not hit it by accident in 3 weeks of commuting. Since I bought this I have seen them for less on DX.

Compared to this one it’s a smaller body and a bit lighter. The build inside my example is also cleaner although very similar lines. Output wise it does seem to throw just a little better and has a slightly less blue tint. I’m using my version of the one in the link with a wide angle lens kit and am very happy with it.

has anyone got a link to reflectors for these lights? SMO or OP or hybrid. seems you never know what your gonna get. and would like to replace a few OP with SMO.

Another link (same seller): http://www.ebay.com/itm/1200-Lumen-CREE-XML-T6-LED-Bike-Bicycle-Outdoor-Sports-Light-HeadLight-headLamp-/280842575847?pt=LH_DefaultDomain_0&hash=item4163859fe7 .

Thanks for this post! I had previously asked about these lights. I like that it's an actual Hi-Med-Low w/hidden strobe. I am confused though about the drive current. You measured at the LED? Did you remove one of the wired off the emitter star and place the meter in-line (as rufusbduck says above)? $31.50 sounds hard to beat with this 4 mode setup.

-Garry