HOW TO – Power a Chumby with a battery pack

HOW TO – Power a Chumby with a battery pack

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Energizer Drytabs Sm
Here a bit about powering a Chumby from an external battery pack, Bunnie writes –

Recently, someone on the chumby forum noted that the Energizer ER-PHOTO battery pack works with the chumby. The ER-PHOTO is a handy little device that essentially emulates a 12V DC wallwart with a pass-through mode, so you can continue to use whatever is plugged into the battery pack while it charges. There’s a lot of devices out there that run off of 12V and use that classic 5.5mm DC barrel jack, so they are certainly handy to have around. As you can see in the photo below, the pack consists of 3x 1800mAh Li-Ion cells, which gives a nominal capacity of 20 Wh; of course, the step-up regulator is probably only 90% efficient or so, and the circuitry in the pack is fairly simple, so maybe it lacks the electronics to safely milk the last drop out of the batteries, resulting in a reduced delivered capacity.

Scott Janousek has a nice little writeup about how you can install the battery pack inside a chumby, although I’d be more than a little bit wary about doing what he’s written up–he’s taken the raw Lithium Ion cells out of their protective plastic housing. The electrical tape wrapping won’t provide adequate protection against puncture or impact (which is possible if you’re carrying around a chumby and you drop it). This can lead to cells catching fire in a way that can’t be put out easily (only class D fire extinguishers work on these fires, and many homes and small offices have only type ABC extinguishers).

HOW TO – Power a Chumby with a battery pack – Link.

4 thoughts on “HOW TO – Power a Chumby with a battery pack

  1. Kevin Reid says:

    The second photo is of a defective battery, which doesn’t seem appropriate for the point of this entry.

  2. KentKB says:

    Hey Kids,
    I just built a Chumby (guts) from the Maker Shed and want to make it portable, I remembered this blog and took an other look at it.
    On the daughtercard that has power in, and sound/USB out, and the reset switch, there is a battery connection. Could this be used for the full 12 volts?
    Or was this for the 9 volt back up? Not seeing it covered in any Chumby Blogs so I am throwing it back to you.


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