I received this flashlight as a gift. I'd seen this style before . . . you shake it to recharge the system. What a great idea!
When I turned the switch on, the light came on. I figured it must have been shaken in transit, or while wrapping the present. I wanted to see how long the light would stay on after a little shaking, so I left it on to discharge the system. It stayed on for 10 minutes, without dimming, but the light was intermittent as I tapped the case, so I unscrewed the lens holder ring to investigate. The insides were easy to remove. I was surprised to see a pair of CR2025 (3V Lithium, non-rechargeable) cells in the battery clips.
Upon further investigation, I noticed that the fine copper wires from the generator coil were broken, but taped down to the internal plastic frame. I had not broken them. The circuit board contained only the LED and a battery clip, along with a wire to the other battery clip. There were two short (about 1/4 inch) copper wires, matching the wires on the generator coil. They were both soldered to the same electrical trace on the circuit board with their other ends hanging freely. Examination with a magnifying glass indicated that they had been broken (pulled, not cut). This could never work as a generator, even if the wires hadn't been broken, since both wires had been soldered to the same point, essentially shorting out the generator. I thought about connecting the wires across the battery with a diode to convert the AC generator output to DC, and to prevent discharging through the coil wires. Before I started that work, I decided to check the characteristics of the generator system. I held my screwdriver near the "magnet" that slides through the center of the generator coil, but felt no attraction. I got a cheap magnetic compass and verified that it could be deflected by residual magnetic field of the screwdriver blade. Then I tried to determine the strength of the magnet in the generator. It produced no change in the compass needle direction. Generally, the stronger the magnet in a generator, the better it works. This "magnetic" slug was less magnetized than my small screwdriver, and appears to be just a piece of metal.
This product is a fraud, designed specifically to trick people into thinking it is one of the clever "shake to recharge" emergency lighting systems. The clear plastic case allows you to see the coil of wire and the "magnetic" slug, typical of these types of flashlights. It must be cheaper to install 3V Lithium cells and mimic the generator than to magnetize the steel slug and provide a diode and super-cap or rechargeable cell. The big words on the packaging are "Just Shake" and "No Battery Needed". It doesn't actually say that the shaking does anything, nor does it indicate that the light stops working when the internal cells are exhausted. The implication is that this is a generator charging system. The text on the back of the package does have one possibly fraudulent claim: "Magnetic recharge method allow LED be recharged unlimited times". If we ignore the poor translation we must substitute the word "flashlight" for "LED", since the LED can't be charged because it is only a light producing device. I hope it didn't cost too much because it sure is cheap!
Here are some pictures of this device:
Front and back of package showing claimed features.
Generator coil showing broken wires.
Circuit board showing both generator wires soldered to same point (and connected to nothing.
Testing to see if generator "magnet" is a magnet, or just a steel slug.
I plan to find the store where this gift was purchased to see if the management knows of the fraudulent nature of this device.
Results of investigation into the source:
I found that my friend got a bunch of the flashlights at a flea-market in Florida. The seller gave him a “special deal” because he was buying 15 or 20 of them. One of the flashlights actually had a real magnet and a super-cap, so it worked!