Adapter for Internal Tablet Battery

Discussion in 'Community Discussion' started by BigMcGuire, Oct 9, 2016.

  1. BigMcGuire Contributor

    BigMcGuire

    Joined:
    Jan 10, 2012
    Location:
    California
    #1
    I took apart an old Samsung Tab Pro 8.4 that I had for years as a fun project (tablet died). The battery was perfectly fine and lasted all day. I was wondering, is there an adapter that would let me use the battery as like an external battery? Images below.

    I imagine that it needs a charger circuitry because the adapter in the photos looks like it directly connects to the battery?

    Also, is it not worth it? I realize using a battery like this can be dangerous too - at least inside of a tablet it is a bit more protected if something bad happens. Just seems like a waste to toss the battery :(.

    [​IMG]

    [​IMG]
     
  2. chown33 macrumors 604

    Joined:
    Aug 9, 2009
    #2
    What do you intend to power with the external battery?
     
  3. BigMcGuire thread starter Contributor

    BigMcGuire

    Joined:
    Jan 10, 2012
    Location:
    California
    #3
    Anything USB - was hoping I could plug this into a device that would charge the battery and allow me to plug in USB devices into it like cell phones, tablets, etc --- to make it act like an external battery for any USB device.
     
  4. chown33 macrumors 604

    Joined:
    Aug 9, 2009
    #4
    Well, the battery itself is 3.8V (it's on the label). USB needs 5V. So in addition to whatever charging circuit is needed, you'll have to add a boost regulator to convert from 3.8V to 5V.

    You haven't said anything about what electronics skills you have. For example, if I suggested a specific charging part number to look at on Digikey, is that sufficient? Or would it be necessary to give complete step by step instructions?

    In general, Lithium-ion battery charging isn't simple. There are dedicated chips for it, but you still need to have at least a few specs for the battery, notably the max charging current and the nominal charging voltage. Without that info, you have to guess, and that can have results ranging anywhere from unreliable to extremely risky. Worst case, the battery will ignite, emitting noxious fumes. There are also non-igniting failure modes (swelling, bursting).
     
  5. BigMcGuire thread starter Contributor

    BigMcGuire

    Joined:
    Jan 10, 2012
    Location:
    California
    #5
    Wow yeah, this looks like it's way over my head. I have almost no electronic skills (beyond basic). Figured it would be a $30 part I could buy on Amazon that lets me plug this into it and do everything else for me. lol. I did some reading on RC charging and how they put them into fire resistant bags while charging them.

    Sounds like it may be more trouble than it is worth to make this an external battery to charge my iPhone with.

    I'd love to hear the step by step if you're ever bored but you don't have to. Really appreciate the time you've spent answering my thread.

    I play a lot with Anker external batteries - charging my stuff with them and charging them with a 21 watt solar panel (all USB for simple minded folk like me). :p
     
  6. chown33 macrumors 604

    Joined:
    Aug 9, 2009
    #6
    A step by step would be really long.

    Here's one charger chip I was thinking of, mounted on a board with other circuitry:
    https://www.adafruit.com/product/259

    HOWEVER, I know that chip comes in several variants, and I'm not sure that the particular version on that board is suitable for the battery you have. In other words, I have no idea if that product is safe for your battery.
     
  7. BigMcGuire thread starter Contributor

    BigMcGuire

    Joined:
    Jan 10, 2012
    Location:
    California
    #7
    Awesome! Thank you! And understood.
     
  8. RedTomato macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #8
    This is a really interesting idea. Over the years I've had to chuck / recycle into the battery disposer a number of Li-ion batteries - various old laptop batteries, old tablets, etc. It would be wonderful to repurpose them into USB recharge banks.

    However lithium-ion electronics are clearly a nightmare for the casual dabbler. What's needed is some sort of general-purpose third-party widget that would be able to take on regulating the charging / discharging / converting to USB voltages duties for various random Li-ion battery units.

    The Adafruit charger chip mentioned above seems specced only for Adafruit lipoly batteries - we need something more general, able to adapt to a wide range of batteries / polarities / voltages.
     

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