5 Volt Chargeable 1.5v Li-Ion Sorbo Batteries Repair
This repair is about replacing often badly soldered or defect special smd charger controller chips in 5V chargeable 1.5V li-ion AA batteries.
In the past I bought several of these Sorbo batteries of which a few of them kept suddenly dropping out in my photocamera while the other batteries kept on working just fine. They have an orange cap that when removed reveals the USB 5V plug underneath them with which they easily can be re-charged.
And the only way to see the pcb with the internal used smd components is by carefully – with some force – sliding off the rectangular USB outside metal plug holder from the plastic top it is firmly clipped onto. I just used a small screwdriver without sticking in to deep, to keep far away from damaging any internally placed components in the process. Also to avoid making any short circuit which easily could damage the internal li-ion cell or worse make it explode or cause any fire.
The first bad battery I opened showed a displaced badly soldered 6 pin smd chip with code marking HXN-MH on top. But somehow the datasheet I found didn’t make sense with charging this battery at all. So it must have been a completely wrong smd code that didn’t match the function it was used for here. Therefore I opened a second Sorbo battery to check if that chip had another smd code marking that made sense. Luckily it had a different marking with code 2DLF. Which showed it was a XT2055 – A Standalone Linear Li-Ion Battery Charger with Thermal Regulation! As next photo shows.
Below shown extract from the XT2055 datasheet shows that the rather crooked placed 6 pin chip indeed is a constant current charger controller with internal thermal regulation control.
Next photo shows the previously badly working 1.5V Sorbo AA battery on which I already removed the badly soldered not working 6 pin HXN-MH controller. On the right of marking R2 and D1 both red and green charging leds are visible. Both are also controlled by our XR2055 6 pin charging chip as the datasheet showed.
All I now needed to do was to check if these parts were available. And after online typing in smd code 2DLF it immediately gave the Aliexpress webpage that sold these in quantities of 10 parts.
Previous photo showed the back side of the battery charger board with the USB plug. And also showed the metal clip on the cap that connects the 1.5V output to the plus pole on the top of the orange cap when placed back on the USB plug of the battery that functions as normal 1.5V plus pole of the AA battery. These this way constructed older AA li-ion batteries however are in the meantime often replaced with newer types that now use a small integrated USB-C charging port instead.
Another second sot23-6 chip on this battery controller pcb apparently is a CT2105 chip. The only datasheet I could find was on Archive.org. The datasheet of this chip is rather complex providing over-/under- voltage and current protection. And again also temperature overheating protection for battery safety. Link to datasheet is here: https://archive.org/details/ct2105-creatic-en Ordering this CT2105 chip on Aliexpress is not as cheap because the shipping costs are with less than 4 euro almost as high as the item price. See below screencopy.
After the replacement controller chips are received and assuming there are no bad battery li-ion cells, the Sorbo AA batteries no doubt will all be fully functioning again.
Albert van Bemmelen, Weert, The Netherlands.
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YOGESH PANCHAL
March 8, 2025 at 3:23 pm
Good JOB! Albert
Indeed two different IC used here one for Battery charging & another is for Protection.
Bruce Saxby
March 8, 2025 at 3:23 pm
Always enjoy reading your articles Albert, you are a great technician and get into all sorts of interesting equipment. I trained in electronics in the early 70s and still enjoy tinkering however limited now without the sorts of tools needed for many jobs.
Albert van Bemmelen
March 9, 2025 at 2:17 am
Thanks Bruce, in my case it is mostly about not having enough time and the energy to do a lot more in electronics with all my tools and equipment at home.
After my daily post delivery route on bike coming home I need the rest to keep up my health for the next day!
Sadly it is not only wisdom that comes with age as you probably know (lol).
Parasuraman S
March 8, 2025 at 8:41 pm
Vow! Another investigative work done and thanks for sharing! Look forward to the updates soon!
Mark J
March 9, 2025 at 4:36 am
Albert well done. Thank you fro sharing.
Imoudu
March 10, 2025 at 4:22 am
Thanks for sharing and wishing you more strength for your daily delivery job.
Albert van Bemmelen
March 11, 2025 at 1:03 am
Thanks Imoudu! If all goes well my present job ends end of next year. Which hopefully will give me much more time to make and build new Electronic tools and to do more interesting repairs.