Fake Batteries Found In Xiaomi Power Bank T10.4
This power bank was bought by my son for a cheap price, knowingly well that it could be a fake, and brought it to me for opening and checking it up. Just see what was inside:
Just one cell along with three heavy plastic battery look alike for sizes. There is no mention ‘made in China’, though we all know these come from there!
In order to study whether I can add three more cells in it, I removed the IC, as the top was blank.
I could not read the IC number, however I tried. So, looking for a possible chance of getting a datasheet was ruled out.
Nevertheless, my son bought three batteries of similar type which I connected in parallel and switched on. It was working fine with blinks. Left it for charging until all the LEDs lit up and tried connecting it to a mobile. The discharge was fine too.
Thus an experiment was successful and my son took it with him for his standby use. Another job done satisfactorily!
This article was prepared for you by Parasuraman Subramanian from India. He is 69 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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You may check on his previous repair article below:
https://jestineyong.com/new-clickon-emergency-led-light-with-battery-management-ic-goes-dead/
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Marco
October 8, 2018 at 7:35 pm
Thank you Mr.Subramanian for this rare repair as its unbelievable the things you find when opening up electronics for repair,but you did a great job,congratulations. So you never found info on ic you removed?,thanks again for rare article.
Albert van Bemmelen
October 8, 2018 at 8:44 pm
Good job Parasuraman! sadly I do not trust some products that were send to me incomplete and also badly soldered through Aliexpress. It concerned two 3 cell lithium-ion charger boards that other sellers sold with all components connected instead of only half of the charger board occupied. Hence why two of the three 3.7V cells exploded while being charged within a day or two! Before I used the incomplete boards I explicitly had asked the seller who had send them if he was sure they were completely safe, knowing other sellers sold that same board with all components attached! He said he was sure so I recently opened a dispute to warn Aliexpress for this seller who sold dangerous products that easily could have caused injuries, fire or worse a burned down house! From the other charger boards that had all components soldered on the pcb another 3 cell lithium-ion battery still works perfectly safe without any incident for many months now! And if like in this repair unknown IC's are used you might as well have build a bomb instead of an USB charger. Therefore better never use it without being at home!
Albert van Bemmelen
October 9, 2018 at 4:31 am
Be aware that by placing 4 cells in parallel also the current becomes four fold that of one cell. Not knowing if the unknown IC qualifies for such a large controlled charging current or discharge current. For instance in Makita BL1860 Li-ion batteries 5 times 3 parallel connected 18650 cells are placed in series for delivering 6 Amps current at 18V. But it also has a safety temperature sensor inside those packs connected to the controller board! And inside in Makita BL1830 battery packs ten of those cells are placed as 5 times 2 parallel connected 18650 li-ion cells and they also have a temperature sensor attached. And those Makita 'clone' charger boards plus plastic case can also be bought online through Aliexpress, Amazon or on eBay. Anyway better be safe than sorry!
Robert Calk Jr.
October 8, 2018 at 9:41 pm
Good job, Parasuraman. I'm glad that you restored life to the power bank!
Mihai
October 9, 2018 at 1:06 am
Hello Mr. Parasuraman,
I have the same problem with the IC's without marking or datasheet.
By the way, good job Sir !
beh
October 9, 2018 at 11:54 am
Great discovery and repair.
Albert van Bemmelen
October 9, 2018 at 6:16 pm
By-the-way: If it is a 14 pins chip it can be a LDR5108. If it is a 16 pins chip it can be a FM9606L.1. Both are for 5V 1A or 2.1A charger banks.
http://www.legendary.net.cn/html/en/news/companynews/201610/879.html
http://www.ic37.com/ETC/FM9606_datasheet_13551788/
Parasuraman S
October 10, 2018 at 10:58 pm
It is 18 Pin!
Albert van Bemmelen
October 11, 2018 at 2:07 pm
I checked the photos of the charger boards that can be bought on Aliexpress for any visible chip markings. There were no 18 pins chips so maybe another Legendary or ic37 chip in their database qualifies for being your 18 pins chip? The site mentioned a few others.
Parasuraman S
October 11, 2018 at 10:06 pm
Sorry, it was 16 pin only. Typographical error!
Albert van Bemmelen
October 11, 2018 at 2:12 pm
You however only showed a 16 pin chip? (2 x 8 DIL smd)
YOGESH PANCHAL
October 9, 2018 at 9:17 pm
GOOD JOB! SIR
Andre Gopee
October 9, 2018 at 11:07 pm
Thanks for sharing and great discovery.
Humberto
October 11, 2018 at 11:39 pm
Great discovery Parasuraman. You saved another device from the dump
Pranav
December 17, 2023 at 2:04 am
I recently laid my hands on a similar device and found the similar goof up. Finally landed here while searching if I could add more cells to it. Dear Mr Parasuraman, was your power bank able to take the load of 4 cells?