Auxiliary battery pack for field operations

portable_battery_pack

Ham operator [Ken - wa4mnt] wrote us to share a small project that he uses nearly every time he goes out in the field. His portable sealed lead acid battery pack (PDF) always ensures that he has a 12v power source at his fingertips, both for fun as well as in emergency situations.

The battery pack is pretty simple, and includes a 12v, 17ah battery strapped into a light aluminum chassis which he fabricated. The battery is secured with zip ties, so it can easily be swapped out or replaced without much fuss. The frame also sports a tiltable 4w, 17.5v solar panel that keeps the battery topped off and ready to go at all times. He stuck a voltmeter to the top of the battery to keep an eye on things, and he employs a 10A fuse to make sure he doesn’t fry any sensitive radio components should something go wrong.

The battery pack is pretty compact when you think about it, and we imagine it would be great to have on hand for a wide array of outdoor activities. Even if you’re not into Ham field operations, it’s hard to argue with its usefulness during power outages.

[Ken] doesn’t appear to have any published plans for the chassis or the electronic portion of the pack, but we’re pretty sure he would share if asked.

Comments

  1. supermunchkin says:

    i’m just getting into fabbing my own stuff and this looks really useful. i would definately like to see some plans if he wants to share them. a pricesheet for the parts would really be awesome :)

  2. sml says:

    Wow very informative

  3. good to see more hams getting their work on HaD,
    I have some 12V 92Ah batteries I use for my Ham gear when mobile (a 100W transmitter with alternator whine? no thank you) and to power other things like football tailgating
    I have been meaning to build them into a proper enclosure of some kind and this makes me want to do it more.

    73!, ke5tuz, Jimmy

  4. strider_mt2k says:

    I wonder if one could come close by simply attaching the movable solar panel to a regular ammo box and building it all inside that to save on the enclosure fabrication?

    -I say that because i would like to add a solar cell like this one to mine that is built as described!

    very very nice hack!

  5. colin says:

    I built a power station a bit bigger which is weather proof it has three 5watt panels and a hand crank from a life boat so that i can charge up batteries in the field. I have a turntable so that i can orientate it towards the sun. A fun but serious piece of equipment for ham radio field days.
    Colin VK2JCC

  6. Rick says:

    Pretty cool setup, although I like mine better. I use it for camping, and even have run cfl lights via an ad/ac adapter for hours without barely draining any of the battery capacity when we lost power from wind. The one thing I would like to see is the digital volt meter working.

  7. N5DUX says:

    @strider_mt2k – you might get close with an ammo box, but you want to be able to vary the angle of the solar panel to some degree to get maximum exposure. If you mount it to the side of an ammo can you won’t get the same elevation without quite a bit more work. If you mount the panel on the lid of the box, you lose the convenience of the handle.

    Wondering how long the battery will run his IC-703 QRP radio and Mag Loop.

    72

  8. Stevie says:

    I like it. It would be useful if you could also plug it into a wall socket to charge. ie when you’re sitting at a table in starbucks and have the batt. pack in your bag :p

  9. dan fruzzetti says:

    Very smart, Ken. I like the use of the (wheelchair?) battery for this purpose. It reminds me of a monster job I did a few years back for a UPS system which had the power but not the time capacity required to pull a 24hr job. Cheers.

  10. leadacid says:

    Does anyone have a recommendation for a solar charge controller? Are the cheap-o eBay Chinese ones any good? I don’t need anything fancy, just something that will charge some SLA batteries from my 12V solar panel without cooking them over time.

  11. Rick says:

    look in my video I linked above and get the charge controller that I have. It’s rated at 10 amps in and out and is microprocessor controlled, so it will work better with your batteries and your solar panel(s). It only costs about $30.

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