A Cheap LED Flashlight

I bought a defective LED flashlight from Kaidomain, because I wanted to use the body as a cache. Kaidomain is quite interesting. They sell a wide variety of flashlights, but they also sell flashlight parts you can pick and choose to assemble your own flashlight. This post is to:

1. See what parts are needed to build a flashlight
2. Investigate build quality of cheap flashlights

This is the flashlight. It was larger than I expected. The body holds 3 AAA batteries, and it's 13 cm long. This cost <$5 USD. Some flashlights cost $10, and some cost $100, for the same type of batteries and brightness. What's the difference? This flashlight shows what you get.

This is the front. The lens feels a bit thin and the LED looks a bit small. The LED isn't centred in the reflector, and in fact there's a gap between the LED and the reflector, so some light must leak into the body.

I like that the back both has a hole for a strap, yet is flat and allows the flashlight to stand on its base - one of the things I'm looking for in flashlights.

The anodisation is of poor quality.

The flashlight unscrews into 4 sections.

The rear spring was corroded.

They can't make up their mind whether to anodise the threads or not. Also, the threads squeak terribly and I think this is the only gap that has an O-ring.

I like the hole for the strap at the back, but inside it looks like it's just hammered into the body of the flashlight. I don't think this is waterproof.

This is the LED and electronics. They're held in by the aluminium ring with 2 dimples, which unscrews.

Aluminium ring removed.

 The LED is exposed and has no lens on it. I think the rectangles might be for heat sinks. I tried applying a voltage to the LED and it lit up! Maybe this flashlight isn't defective!

The back of the LED module. Electrical contacts are the centre and side.

This is the switch. The big black block is just a block of plastic to hold the switch in place. To assemble it, you put the switch against the hole in the body, then slide the block behind the switch to fix it in place. Then bend the contacts to hold the block in place.

I fiddled with it a bit and managed to get it working! Unfortunately it's very unreliable and doesn't work most of the time. I don't think there's anything wrong with the parts, just that the connections are no good. Probably the switch contacts - they have to be centred in the body of the flashlight to connect the LED module and battery carrier, and the don't look centred.