Dorcy 41-4416 light, trying to explain flickering

LED Flashlights – General Info Multiple AA / 14500 Flashlights
1

I’ve had this light for several years, it runs on 3AA alkaline batteries, but i’ve been using it with NiMH

It draws 0.5amps with alkaline, and 0.37amps with NiMH.


Images are clickable for full size

Is this some sort of circuitry?

There is no pill, this is the back of the star inside the light, i haven’t figured out how to get it out yet.

I haven’t been able to replicate the flickering on demand when i have a multimeter connected to it, so i can’t tell if its getting power while its not running. I can’t take the switch apart, the light uses an XP-E led, i have no clue which tint or bin. Sometimes it will go out and not turn on till i bang the head.

http://www.dorcy.com/p-378-41-4416-200-lumen-focusing-flashlight.aspx

2

bump

3

Same exact thing happened with my sk68, until I took it all apart, screwed everything back together, and then cleaned the threads. Now it works totally fine.

4

I can’t get the switch apart, its a weird twist on and momentary on combination, otherwise i have done everything else i can

5

Looks like an XP-E with a simple resistor for the circuit instead of straight direct drive. Flickering is most likely in the switch end.

6

I came to the same conclusion on the XP-E, but i have no idea which bin, the 1R0 is a resistor? Whats the resistance value?

7

It looks like a 1-Ohm resistor.

8

So the light is designed for 3 x 1.5V alkaline AAs, and i’m using a NiMH, what would the resistor do?

9

Probably shave the voltage down from 4.5 to a more LED friendly 3.3 or so. I’m sure one of the better electronic guys could tell you exactly.

10

I finally got the light to act like it was not a car at the mechanic, i was able to measure voltage while flickering.
The readings were from 0 to 2.18 volts when the led was out and back to 3.56 volts fully lit with ~50% charge NiMH.
I was able to fix it by cleaning the positive battery terminal shown below in the center, but the tarnishment is still there and doesn’t seem easily removable.

The hole on the right is connected to that positive terminal in the center, and the outside ring with the hole on the left is the negative. Any ideas on how to clean the tarnishing to prevent flickering (i think its aluminum, maybe the thickness of aluminum foil), or i was thinking i could use a ring that would make a larger contact then the positive point of a battery, but it can’t be big enough to cause a short. How could i make this work if tarnish cleaning is not an option?

</Holy batman thread revival>