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Battery percentage

thorssonmaxthorssonmax
in Hardware

Hi,
I had some problem with the haptic module that were soldered on the board (MetaMotionR) from delivery. It did not work at all at (since the soldering was not enough) I fixed this myself, but after some time it stopped to work again I had to re-open the case to fix this. At this time when I opened the case again and the battery cables felt of, and stopped to deliver power to the board. I soldered them back and now the board and sensors + haptic module works fine but the power percentage is very strange. At most times the percentage is at 6-7 % and after a charging of 12 hours it only goes up to a maximum of 27 %. The percentage does not seem to change in a realistic manner either... When connected to USB its at 100 %. I've done readings of the battery percentage with the MetaBase app on Android and Windows and the MetaWear app on Android. I've updated the board to latest firmware and done a reset. I've also tried to charge the board from USB port at a PC, Powerbank and charger, with different USB cables.

Can only the readings be faulty or is something broken?
Thanks.

Comments

  • EricEric
    • How are you reading battery percentage?
    • Try reading battery percentage until the battery is dead, recharge it 100%, then try reading again
  • thorssonmaxthorssonmax

    I read it through the MetaBase app. It has now completely charged out. I thought It was dead but it appeared when USB and was firstly at 3% when disconnected from charger and now at 6%. I will charge it for one hour ad check if it changes.

  • thorssonmaxthorssonmax

    It's at 18 % according to the MetaBase app after 7 hours of charging.

  • thorssonmaxthorssonmax

    after 8 more hours of charging the battery is dead again and now at 6 % after 10 min of charging...

  • LauraLaura
    edited February 2019

    @thorssonmax,

    Sounds like a dead battery. Is it puffy or weird looking in any way?
    Can you fill out an RMA?

  • thorssonmaxthorssonmax
    edited February 2019

    @Laura,
    Thank you. I can do that yes. But this board has passed the 30 day warranty? I can't see anything weird with the battery. Except I had to solder the wires, back like I mentioned, prettier soldering exists. Still I don't understand if that could cause the error and how to solve it - I've spent 12 hours trying to fix this, just want it to work properly.
    The battery dies very quick. Now at 3 % after charging over night again.

  • thorssonmaxthorssonmax


    Would you consider it puffy?

  • LauraLaura

    @thorssonmax,

    Generally you can tell it is puffy if you feel it (when you press the battery, you can feel there is an air space/gap inside). Please get back to me on this.

    How long has it been since you ordered?

  • thorssonmaxthorssonmax
    edited February 2019

    @Laura
    Almost exactly one year, I can see in my email it was posted 2/20/2018.So it arrived a couple of weeks after that. I have the packing list, with order no. also. The main issue was then already that the cables were not fully soldered to the board. I understand its difficult stuff, it's very good the new ones has melt glue also.

    I can't say that I feel that the battery is puffy when pressing it.
    Thank you.

  • LauraLaura

    @thorssonmax,

    Do you have a technician or engineering buddy handy that could solder a new battery on for you?
    You can buy lipo batteries at your local hobby store, on amazon or even on our store: www.mbientlab.com/store
    https://www.amazon.com/YDL-2000mAh-battery-Rechargeable-Connector/dp/B07BTVT2HH/ref=sr_1_16_a_it?ie=UTF8&qid=1550089062&sr=8-16&keywords=small+lipo+battery

    Keep me updated.

  • thorssonmaxthorssonmax

    If you believe it its the battery, can I do measures with a multi meter to make sure it is the problem? I can fix one from a friend in the weekemd. What should I expect in volt and ampere?

  • LauraLaura
    edited February 2019

    Here is some info:

    • if battery is 100% charged and with no load, expect 4.0-4.2V
    • if battery is greater than 3.8v it is nearly full and working
    • if battery is 3.0V or less, it is fully discharged (it it stays at or below this, the battery is dead)
    • You want to avoid any load on the system so forget current measurements (don't turn anything on, maybe even put the sensor to sleep if you can)

    First, check the voltage as it is currently, then charged it for 2 hours and check again.

    Report back.

  • thorssonmaxthorssonmax

    Can I trust the voltage reported that I get from the Python package or should I only trust the multimeter (can't check that until weekend).

    Thanks again for the help (:

  • LauraLaura
    edited February 2019

    You can't trust any software values. Even hardware values (with a DMM) I typically don't trust unless done by a professional engineer. :)

  • thorssonmaxthorssonmax

    @Laura
    The voltage seemed very low, at 0.3 V and only got up to 3.3 V which held for some seconds after it had been charged. I've ordered a new battery from your store. I'll let you know if it works!

  • LauraLaura

    @thorssonmax,
    Thank you for confirming the dead battery. It should work just fine with the replacement. Re-start this thread if you have any issues with the new battery.

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