Hacklet 39: Battery Power

3296371398740598106[robin] has a Red Camera (lucky!), an absurdly expensive digital video camera. As you would expect the batteries are also absurdly expensive. What’s the solution? Battery packs from cordless drills.

Cordless drills are interesting pieces of tech that can be easily repurposed; there are huge battery packs in them, big, beefy motors, and enough hardware to build an Automatic Cat Feeder or a motorized bicycle.

What if those old Makita batteries don’t charge? That usually means only one or two cells are dead, not the whole pack. Free LiIon cells, but you need to charge them. Here’s a single cell charger/boost converter that will do the trick.


A problem faced by amateur radio operators around the world is the lack of commercial power. Plugging a portable shack into a wall will work, but for uninterrupted power car batteries are everywhere. How do you combine wall power and car batteries for the best of both worlds? With an In-line battery backup module.

9k=All of the projects above rely on charging a battery through wall power, and sometimes even that is impossible. Solar is where we’re headed, with solar LiPo chargers, and solar LiFe chargers. That’s more than enough to keep a smartphone charged, but if you want to go completely off the grid, you’re going to need something bigger.

[Michel] has been off the power grid 80% of the time since he installed his home PV system a few years ago. How’s he doing it? A literal ton of batteries, huge chargers, and a 5kW inverter.


8 thoughts on “Hacklet 39: Battery Power

  1. Interesting/entertaining note on Wikipedia about the Red Camera vs. Sony…

    In February 2013, Red filed for an injunction against Sony, claiming that several of its new CineAlta products, particularly the 4K-capable F65, infringed on patents the company held. They requested that Sony not only be forced to stop selling the cameras, but that they also be destroyed as well.[39] Sony filed a countersuit against Red in April 2013, alleging that Red’s entire product line infringed on Sony patents. In July 2013, both parties filed jointly for dismissal, and as of July 20, 2013, the case is closed.[40]

  2. By the way, you want to move that micro USB connector to the left so that the silk screen outline is flush to the edge of the PCB. Part of it (flange?) is supposed to overhang. Otherwise you’ll have to do some hand filing or the connector won’t seat level to the board.

  3. Mhh… recently I got a laptop battery pack that was ead. I opened it up and found 6 Cells (2 paralel, 3 series). The addup was 3.6V + 3.6V + 2.66V. My understanding after some reading was that The 2.66V is not really bad it just happens to be under the cutof. Could I use the single cell charger/boost converter to lift the 2.66V cells back up again to 2.8-3.0 so it can be charged again fine?


      1. Oh really? I thought LiPo charging would need a ramping pattern or some kind of curve to follow while charging. What values would you advice for waking up a 2.66V cell? How long on what setting?

    1. Ideally you use an intelligent chargers like the ones they use in RC that has charge balancer circuits that balances voltage distribution of the cells during charging. You can also use the charge analyzer to find out the capacities of the 3 series cells.

      The capacity of the cell(s?) in the last chain might have been deteriorated over time and/or more more leakage, so you are only extending their life.

  4. So I was sat in my hotel room in Dublin, blearily checking HackaNews, not real news cause thats just full of death, distruction, football and celebrities.. Urgh.. When I thought, “Hang on, Hang on a minute, that circuit looks familiar!” Thanks Hackaday for showing my project ( The Li Ion one….)

    Thats one of my nerd Life list accomplishments done, (I hate the phrase bucket list, as it implies I’m going to die, which I’m not planning on….) and Tekkieneet, the connector seems to fit fine, I could have bunged it flush to the edge for OCD purposes, but its only raised about 0.05mm, which I can barely see, even with my new glasses….

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