Beam shape changing when shaked

Callback79

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Joined
Sep 30, 2017
Messages
3
Hi,

I'm trying to figure out the problem with my bike light. If the light is shaked from left to right, the round beam takes a vertical oval shape. If I shake the light from top to bottom, the beam take a horizontal oval shape. As I said, it is a bike light, so it shakes each and every seconds. The sudden change of shape gives a blinking effect, but the light is not blinking, only the hotspot is going from round to almost flat, so a lot less light in the middle. Btw, it is a Derlson bike light bought online. Is it something that can be fixed or is a problem seen in cheaply made light ?

Thanks.
 

Keitho

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Jun 7, 2017
Messages
781
Location
CO, USA
That light looks like another variety of Chinese light that I used for awhile, and my wife still uses almost every day (mine say "Shenkey" on them, but the design looks identical, and they probably come from the same place). I haven't seen that behavior before, but I did take one of them apart to see how waterproof it actually was, and how it was put together. It wasn't hard to take apart, and I remembered thinking that I might have to add some potting or glue at some point, or re-solder some of the very thin-gauge wires if they ever broke. If I had to guess, I'd say that the circuit board that holds the LED is rattling around behind the reflector, creating odd effects in the beam. See if you can take it apart, if you don't mind spending a few minutes and risking $20. You might find something obvious that is moving around that shouldn't. Good luck!
 

Callback79

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Joined
Sep 30, 2017
Messages
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Yes, Shenkey light looks to be the same. Did you take apart the light just by unscrewing the 2 micro screws ?

I don't hear or feel any rattling, and just by the look, the led seems like it is centered and well placed.

Is your light get dimmer after a while when you use it or it keeps the same power output and then shut off when there is no more power in the battery ?
 

Keitho

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Joined
Jun 7, 2017
Messages
781
Location
CO, USA
Yes, 2 screws on the front of mine, allows the front to pull off the back. There was actually an o ring between the two to keep it splash proof.

Mine keeps pretty good brightness on high for 70-90 minutes, then is starting to get noticeably dimmer. I was able to find the battery on Alibaba and eBay by typing in the number that was printed on the cell--if you are getting a prematurely dim light, you might want to play around with it to see if a new cell is better. I haven't done it myself, but it looked straightforward.
 
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