M5StickC Plus - quality control issue

  • Hi guys

    I have two M5StickC Plus devices and when they arrived the main batteries were flat - which was to be expected. So I connected USB and powered them up for the first time with the stock factory firmware and I noticed that on one device the time started with all zero (e.g. 00:00:00) on the time screen while the other device had something not all zero. I figured, well, the RTC backup battery must have been flat on that device too, but didn't think much of it.

    Until today, when I decided to open up the device in question to do some current measurements. Doing so I found the reason for the flat RTC backup battery - the plus and minus pols have been shorted with solder (see picture below). I guess that happened when the RTC backup battery was soldered to the board. I've fixed that and the RTC backup battery seems to be charging slowly now. I guess only time will tell if that caused permanent damage to the RTC backup battery or not.

    Thank you for listening and hopefully my report can help you guys to improve your quality control process.



  • Hi @felmue I'm deeply sorry for the late reply.
    I can assure you we are looking into this quality matter as it's extremely important to us, we've already made and will continue making changes in our factory / supply to ensure top quality products to our customers.

    Regarding the battery, it's an issue came to our awareness regarding the poor soldering (manual soldering) that we looked into and solved, it won't happen in the next products that go to market.

    We've showed our engineer the issue and we replicated it, for the long term there is no expected damage to the battery or the circuit so once you've fixed it - it should work properly, no long term effects you need to worry about.

    If you are having any troubles or issues, please email me at roni@m5stack.com.

    Also, I will greatly appreciate it if you could comment here the order/serial number of that product so I could check the batch and the production date if there are any extra issues happened that time.

  • Hello @Zontex

    thank you for checking with your engineers regarding possible long term damage for the RTC backup battery. It's good to know there is none expected.

    This M5StickC Plus was part of order M5-8036 and the serial number is (I think):


    In case that is not the serial number, then please kindly let me know where I can find it.