20800Mah USB Charger

Discussion in 'Electronics & Electrics' started by toje, Sep 16, 2014.

  1. toje

    toje Member

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    Hey Guys,

    So it all started a few days ago, when installing my Rasberry Pi in a weather proof box outside I needed to solder a few wires, and charge my LED torch,
    Then since the charger I use for that can do Lipos, NiMh, NiCd, Pb, practically anything I went on a bender seeing if any old batteries held a charge.

    [​IMG]

    And I find a battery I forgot all about, an old 10400Mah battery for a eeePC 701
    Like this: http://www.amazon.co.uk/Extended-Battery-Black-10400mAh-CS-AUA2DT/dp/B001BP8Q5O

    Since I don't have a 701 anymore, I cracked that sucker open.
    And what do I find 8x 3.7 volt cells
    [​IMG]
    I suspect Knock offs but they are ICR18650's

    I pulled them apart and charged 4 of them, all held their charge.
    [​IMG]

    And while doing it I came across an old Energizer USB charger, turns out only the cell was dead, a single 3.7V 2000mha cell, so I ripped out the PCB and tested
    [​IMG]
    The PCB Seems fine, even putting out a good voltage for charging.

    With a single cell.
    [​IMG]

    Seemed to be perfect, so I made the cells into packs of four and tested again, with charging for my sake, all worked exactly as expected.
    [​IMG]

    You may notice the fan evolved as well, using an old PSU case for it.

    Charged the last 4, they seemed rather happy to drink the amps down.
    [​IMG]

    Now packed up in the pack of 8, and a 5amp fuse for it. ALl wired in parallel.
    [​IMG]
    (been making new adapters and sticking Anderson plugs on all the things.)

    Packed it in a Small Duratech case, and now waiting on a final step up PCB to do 5V 1.2Amp and 5amp blade CB
    [​IMG]

    It was ranter spontaneous, but it can charge my phone from flat without even impacting on the Battery lights on the PCB, :)
     
    Last edited: Sep 16, 2014
  2. dakiller

    dakiller (Oscillating & Impeding)

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    Those 18650 cells that they use in laptops provide quite a bit of power. I got a bunch of Raspberry Pi's running on single cells that have 8 hour run times, and I was only going for 1 hour to start with at a guess. Though I did pull the linear regulators off the Pi PCB and replace them with switching supplies for the 3.3v and 1.8v that the Pi uses most of its power on.
     
  3. OP
    OP
    toje

    toje Member

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    Well the RPi uses a UPiS http://www.pimodules.com/_pdf/UPiS Module.pdf

    [​IMG]
    PCB on top of the Pi, its got a 1150mah cell, so if I come across more I will probably give it the same treatment.

    Still I am overjoyed at the energy density.
     
    Last edited: Sep 16, 2014
  4. dakiller

    dakiller (Oscillating & Impeding)

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  5. OP
    OP
    toje

    toje Member

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    Thats a damn good setup.
     
  6. merlin13

    merlin13 Member

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    Well done. Envious on that Duratech case as well...

    I've been cracking open "dead" or sick laptop battery packs 'n scrounging the good cells to run various LED 'n low-power stuff around the house for a while now, also been acquiring a few USB to 3.7 Lithium charger and 3.7 to 5 volt converter boards off eBay ('bout a dollar each...) and strapping them to the individual cells as well.

    Just having fun finding enough small solar panels At The Right Price. :)
     
  7. OP
    OP
    toje

    toje Member

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    I have a bunch of old BP panels for my Truck that I use,

    At the same time the other 5v PCB came in, and it only does 500mha, sigh.

    Takes several days for the USB charger to charge this as expected, but its great. I am still pretty happy with how its turned out.
     
  8. OP
    OP
    toje

    toje Member

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    [​IMG]

    Well the new PCB came. Its pumping out the amps.
     
  9. High-Fidelity

    High-Fidelity Member

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    That's a nifty looking board that you've got the Pi plugged into there. Any more details on it?
     
  10. dakiller

    dakiller (Oscillating & Impeding)

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    It's something I designed myself.

    POE powered with Ethernet as the only connection to the unit, there's a POE controller that gives out 48v.

    Down converted to 4.3v to charge an 18650 cell, gives the unit ~6-8 hours runtime.

    The 4.2v from the battery is fed into 5v, 3.3v and 1.8v regulators, as I pulled all the linear regulators off the Pi for more efficiency and less heat (now the B+ is out with switching regs onboard, that would have saved me a lot of effort)

    The USB and Ethernet connectors removed from the Pi to route those connections through to my PCB.

    One USB port is connected to an AVR that is acting as a keypad controller, so the 0-9 keypad looks like just a regular keyboard to the operating system.

    The other USB port for the most part isn't used, but the header on the PCB allows connection to a full keyboard/mouse and other things for development and future expansion for whatever other applications this might get used for later.

    An LCD I found, connected via SPI using the fbtft drivers.

    The terminals are for employee time and job tracking at work. A small Java UI pushed data to a local SQL database on the unit that is synchronized and replicated to 20 other units as well as a central database to provide a system that will run seamlessly with some serious infrastructure downtime.
     
  11. High-Fidelity

    High-Fidelity Member

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    That's really neat. Looks like a great solution. Are the design files something that you're able (and/or willing) to share?
     

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