I've got too much time, and decided to come out with this post
Above is a power-bank that I got off Qoo10. It is advertised as featuring a Samsung SDI battery. I don't really believe what the seller state nowadays, especially power-banks, therefore decided to took apart the battery.
The disassembly revealed the cell that is used to power our electronic gadgets. Information as below...
2D52 means the cell is manufactured in 2013 at Week 52 (from my research)
There are two LED indicators on the IC chip itself to display the charging and charged status
How the power-bank works is that the 3.7V voltage from the battery is stepped-up to 5V by the IC chip and then supplied via the USB port. But how safe is the power-bank itself against short-circuit?
I've tested the power-bank by purposely short circuiting mine. The power-bank disabled itself from further charging. Just when I thought that the power-bank is spoilt, I took it to charge and volia, it worked again! I'm thinking the charging procedure basically grounded the shorted circuit in the power-bank and made it work again.
One point to note is that one of the poles of the battery is soldered onto the wire itself. According to Samsung specification, manufacturer aren't suppose to solder the wires directly onto the poles on the battery. Considering that the power-bank is just SGD$4.90, I'll let it go.
I've also tested the power-bank using a multimeter to ensure that it was outputting 5V. The results is that the output voltage fluctuates quite a bit. Minimum from 4.9V to about 5.1V MAX. So it definitely outputs the right voltage. I wasn't able to test the Amperage as a load is needed when measuring.
I did a full charge of the power-bank and used it to charge my iPhone 5 from a completely dead state to full. In fact, I was quite surprised that it is able to charge it once. I've had another power-bank before that is also rated at 2600mAh, but only able to charge my iPhone 5 to 80%. That is also the reason why I am so skeptical about the capacity of those power-banks sold out there online.
The enclosure of the cell is pretty weak/fragile, so you might want to keep it away from liquid, etc. I mean water can very easily seep into the power-bank internals causing all around short circuit or even explosion...
In overall, the power-bank was a pretty good deal at just SGD$4.90 + SGD$1.00 for shipping
That's it :D
DISCLAIMER: I'm just doing this for fun and NOT to help the seller boost sales in any way
PS. I don't even know the seller at all......
As always, take care and I'll see you soon :)
Signing off @ 3:23am
Updated: 20 Aug 2021
Dazhong Primary School
Bukit View Secondary School
(Diploma in Computer Engineering)
University of Wollongong
(Bachelor of Computer Science - Digital System Security with Distinction)