What's inside a fake solar flashlight - Page 1
Forum section: electronics / general

author: Homer J Simpson
author_rank: Super Contributor
timestamp: October 25, 2017, 02:34:53 am
content: ??

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 25, 2017, 10:39:08 am
content: Quote from: wilfred on October 25, 2017, 04:30:17 amAll solar flashlights have a battery. What's real or fake is the solar cell, some even have disposable batteries and an unconneced real solar cell.

author: rdl
author_rank: Super Contributor
timestamp: October 25, 2017, 12:29:56 pm
content: The solar cell in this "fake" solar flashlight was real and worked, but for some reason it wasn't connected. The battery was a standard CR2032, so I guess it didn't make much difference.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 25, 2017, 12:56:41 pm
content: Quote from: rdl on October 25, 2017, 12:29:56 pmYes, exactly as I said, they will use a real solar cell so you can't tell the difference (fake ones are just painted glass or even cardboard) then just cheap out and use disposable batteries.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: October 25, 2017, 05:01:39 pm
content: Probably as well it wasn't connected. Those coin cells can go with quite a bang if they are made to gas.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 25, 2017, 06:13:05 pm
content: Quote from: IanMacdonald on October 25, 2017, 05:01:39 pmBut...that's exactly what that POS product deserves.DO IT!

author: calexanian
author_rank: Super Contributor
timestamp: October 25, 2017, 07:26:12 pm
content: I would not call it fake. I would call it dishonestly manufactured and sold. the problem is a proper rechargeable 3.6 volt battery would be more expensive to buy single piece than i assume the whole thing cost. At least it was a genuine solar cell. Use it for some other project or something.

author: kalel
author_rank: Frequent Contributor
timestamp: October 25, 2017, 07:58:45 pm
content: Quote from: calexanian on October 25, 2017, 07:26:12 pmIn case there is a charging controller in there, I guess if one wanted to make a real solar flashlight from it, you could add a LIR2032 battery (or different size, whatever the current battery size is). From Ali, 20pcs cost 8.54, so 0.427 per piece. For manufacturers at multiple thousands of pieces, it would be a lot cheaper, but those lamps probably have to use the cheapest possible parts.Getting a single unit IS more expensive, so possibly one of the cheapest options is currently 4pcs / $3.2, $0.8 per piece. These also are not tabbed, and would need direct soldering and some kind of tape or non conductive glue used to provide proper insulation. Soldering batteries is not impossible, as Dr Carlson (and surely others) have demonstrated. With these cr/lir types, adding insulation before should help prevent shorts during the process.But, most likely there is no charging circuitry, in which case there's no way to really make this properly. I doubt there's enough space in the lamp case to add anything.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 25, 2017, 08:35:34 pm
content: You don't use lithium cells for this kind of cheap thing, only for high end ones. For cheap ones you just need some Ni-Cad cells and a diode, which makes faking it all the more shameful given it's so easy to make real ones.

author: Don Hills
author_rank: Regular Contributor
timestamp: October 25, 2017, 11:50:44 pm
content: I have 2 that look just like the ones in the video. They have real solar cells, wired via a diode to a LIR2032. 3 LEDs in parallel, with a small resistor. I make sure not to leave them face up in bright sunshine...

author: rdl
author_rank: Super Contributor
timestamp: October 26, 2017, 07:35:57 am
content: This is what's wrong with a lot of stuff made in China, you never know what you're going to get from one day to the next. Yours were obviously made on a day they had all the correct parts in stock, the one in the video wasn't.Quote from: Don Hills on October 25, 2017, 11:50:44 pm

author: Zero999
author_rank: Super Contributor
timestamp: October 26, 2017, 10:01:40 am
content: Quote from: calexanian on October 25, 2017, 07:26:12 pmI haven't watched the video.Is the solar cell really genuine? Does it work and output the specified current and voltage? I've seen one of these before with a faulty solar cell, which was connected, but when tested, it only outputted a tiny fraction of the current specified on the data sheet.

author: tszaboo
author_rank: Super Contributor
timestamp: October 26, 2017, 10:12:42 am
content: This is like those single use "emergency chargers" which have a secondary battery in them.It doesnt matter if you call it fake or misleading or anything.It is a product, that just shouldn't exist.

author: kalel
author_rank: Frequent Contributor
timestamp: October 26, 2017, 07:04:15 pm
content: A diode (to protect the solar panel) doesn't seem sufficient as a charging circuitry for a lir2032 / lithium battery.My question is, how much current could such a solar panel provide, and what are the dangers associated? How likely is the battery to explode/implode/cause fire?The videos I've usually seen where batteries start to went out are forced to do so with really high current (short circuit or overcharging at some huge voltage), but from that I can't learn much about something like this product and associated risks.

author: ruffy91
author_rank: Regular Contributor
timestamp: October 26, 2017, 09:54:39 pm
content: I have a few dozens of such solar lamp keychains. They use cheap chinese SuperCaps.I will try to get further information.

author: Don Hills
author_rank: Regular Contributor
timestamp: October 26, 2017, 11:37:36 pm
content: Quote from: NANDBlog on October 26, 2017, 10:12:42 amBig Clive took one apart recently, it actually had a standard (rechargeable) Li-ion cell in it. Ditto a disposable e-cigar. It's presumably cheaper to use a rechargeable Li-ion than the secondary cell version.

author: tszaboo
author_rank: Super Contributor
timestamp: October 27, 2017, 10:50:10 am
content: Quote from: Don Hills on October 26, 2017, 11:37:36 pmOK, so:rechargeable battery = secondary batterySingle use battery = primary batteryJust look up the definition please.

author: Don Hills
author_rank: Regular Contributor
timestamp: October 27, 2017, 10:29:04 pm
content: My apologies, you're right. I misread your original post.

author: timb
author_rank: Super Contributor
timestamp: October 28, 2017, 01:39:04 am
content: Quote from: Hero999 on October 26, 2017, 10:01:40 amYes, the cell was genuine. Inside the flashlight was a stacked pair of CR2016s with welded tabs, soldered to a PCB with a microswitch and the white LEDs.The PCB assembly was stuck to the solar cell with double sided foam tape. There was no connection from the cell to the board and no provisions for such a connection.The solar cell looked to be a real unit made by QSolar, with proper solder tabs and all. He got a voltage out of it, so it was functional.Bizarre.