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MEXICOWANDERER's avatar
Apr 13, 2017

Gyro Gearloose Do It Myself Super Cap 5 Volt Battery

Most of the stuff I have uses 5 volt on-board USB battery charging. 3.7 volts operating systems?

And here I sit looking at a bargain of four-Farad 5.5 volt supercaps.

And a distinct lack of experience with the behavior of supercaps used as batteries.

With my lab power supply I can e-a-s-e recharging into the caps no matter if it takes 4-days to recharge. Four farads is a lot of stored energy. Four supercaps would be an enormous reservoir. Recharge my Samsung, my Nook and everything else so many times it isn't funny without need to worry about power. This means extended bus rides with the Nook Glow Light at full song...

Enthusiasm. Yeah right. How long, intrinsically would the caps hold a charge? How picky are the 3.7 volt regulators inside the devices? Do they all fall flat on their collectors at 4.7 volts? I've tried to research this and hit a solid wall of ambiguity. Some of the "expert" info is laughably naive.

Fondling a full-size laptop in a bus seat ain't gonna happen to tap into a USB port.

5 Replies

  • I could user some of TinkerBells fairy dust
    Lighten my batteries some , less chassis strain,
    then lighten the whole coach
    My fuel mileage would increase tremendously
  • GordonThree wrote:
    MEXICOWANDERER wrote:
    Thank you....energy time and money expended....

    A minimum.

    Now back to those eBay 10,0000,00,000 milli amp hour miracle battery packs...ooooo do you suppose chinglish error (?) nano amperes (?)


    Yup. I love the scam "inverter generators" they sell that's nothing more than a few lithium ion batteries and a junk msw inverter. 1000 watts they claim, ya, right, using eastern philosophy math maybe?

    Ah, but you forget about the magical pixie dust they sprinkle inside those "generators"! :D
  • MEXICOWANDERER wrote:
    Thank you....energy time and money expended....

    A minimum.

    Now back to those eBay 10,0000,00,000 milli amp hour miracle battery packs...ooooo do you suppose chinglish error (?) nano amperes (?)


    Yup. I love the scam "inverter generators" they sell that's nothing more than a few lithium ion batteries and a junk msw inverter. 1000 watts they claim, ya, right, using eastern philosophy math maybe?
  • Thank you....energy time and money expended....

    A minimum.

    Now back to those eBay 10,0000,00,000 milli amp hour miracle battery packs...ooooo do you suppose chinglish error (?) nano amperes (?)
  • Sounds fun, but if you look at the joules provided by 4 farads, it really isn't that much. I think a single 18650 lithium ion cell has more joules.

    Capacitors are getting there. The new ULTRA capacitors with ratings at 100s of Farads catch my eye now and then, but they're physically large, and like you said, need to limit the charge and discharge current, very easy to melt things.

    Self-discharge on caps isn't instant, but it's much worse than batteries. Probably days or weeks before most of the magic leaks out.

    On board chargers don't tolerate much deviation on input voltage ... 4.7 to 5.1 v is what I'd expect from a 5v nominal lithium-ion charger in a small gizmo. They want at least 4.1v for charging the cell plus a several 100mv for overhead and drop-out voltage.

    There's some promising results on the web using 5v buck-boost converters (cheapo from ebay work) with two series 2.7v ultra capacitors (100+ F) The initial 5.4v gets bucked down to 5v, and then boost kicks in all the way down to around 0.8v, so you suck most of the joules out of the caps.

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