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Solar Rechargable Robot Battery Pack — Parallax Forums

Solar Rechargable Robot Battery Pack

mindrobotsmindrobots Posts: 6,506
edited 2014-07-20 08:54 in General Discussion
This looks like an interesting hackable power supply for a Robot. I'm thinking the robot could be very "cat like" when it isn't busy, it cold wander off to find a sunny spot, enable the solar charger (currently a button push) and switch to low power mode while it sits charging in the sun.

The $20 price tag doesn't seem too terrible for a 5000mah LiPo with a solar charger.

Comments

  • kwinnkwinn Posts: 8,697
    edited 2014-07-10 08:47
    Sounds like a pretty good deal. As for the robocat, why have to enable the charging. Let the solar cell supply whatever current it can all the time and have the robocat find a sunny/bright spot whenever the charge on the battery gets low.
  • GadgetmanGadgetman Posts: 2,436
    edited 2014-07-10 08:54
    IT would end up being very catlike...
    'Sleeping' 20Hours/day or more...

    I doubt that panel gets you more than 1W at 5V.
  • mindrobotsmindrobots Posts: 6,506
    edited 2014-07-10 09:12
    kwinn wrote: »
    ... As for the robocat, why have to enable the charging....

    The only reason I mentioned that was because it has a "push button" and it sounded like that needed to be pushed to enable the charger as if the solar panels aren't feeding the charger at all times - needs to be investigated further.
  • mindrobotsmindrobots Posts: 6,506
    edited 2014-07-10 09:13
    The output of the solar cells was my other concern. It may not be enough to keep the cells topped off with a reasonable nap in the sun.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2014-07-10 10:12
    I wonder why I can only find these in Taiwan for 3x the price... if at all.

    There is an inherent design conflict --- you leave it in direct sun (like the dashboard in your car) to charge and the battery cells are getting exposed to excessive heat damage while charging.

    Seems like another day at the offcie where the marketing department and the engineering department are not on speaking terms. Do I add on a Pelteir Cooling Module and have that rob all the charging ability? Or do I just forget the solar cells? Or do I just not tell the customers that it won't last?

    Are we attracting bees to honey? Or flies to that other stuff?

    The real value -- At $20, just buy it and never use the solar charger.
  • ercoerco Posts: 20,256
    edited 2014-07-10 12:54
    Nice find, Rick! Naturally you got me hunting for a better deal... :)

    $16, solar, 12000+ verified mAH, US seller, flashlight. He admits the 30000 mAH rating is bogus.

    http://www.ebay.com/itm/30000mAh-Dual-USB-Portable-Solar-Battery-Charger-Power-Bank-For-Cell-Phone-Red-/251543819512?pt=US_Cell_Phone_PDA_Chargers&hash=item3a912e14f8#ht_6713wt_932

    Or non-solar (USB charge) 50,000 rated (assume 20,000) for $20, another US seller. In pink!
    http://www.ebay.com/itm/NEW-50000-mAh-UNIVERSAL-Portable-Power-Bank-Battery-charger-for-mobile-devices-/261520802969?pt=US_Cell_Phone_PDA_Batteries&var=&hash=item3ce3dac499#ht_3531wt_1661

    Certainly the 5V boost circuitry has some losses. If you drew power directly from the internal 3.7v LiPo battery, you could improve efficiency.
  • mindrobotsmindrobots Posts: 6,506
    edited 2014-07-10 13:05
    erco wrote: »
    Nice find, Rick! Naturally you got me hunting for a better deal... :)

    $16, solar, 12000+ verified mAH, US seller, flashlight. He admits the 30000 mAH rating is bogus.

    Thanks! My work here is done!!

    Dual USB sounds better. Plus a headlight....I mean flashlight!
  • ercoerco Posts: 20,256
    edited 2014-07-20 06:52
    I got one but I'm returning it. The whole thing is bulging like the internal Lipo is ready to blow. The aluminum case and solar cell are convex. Not good. Seller agreed to return.
  • kwinnkwinn Posts: 8,697
    edited 2014-07-20 07:23
    Loopy Byteloose wrote: »
    I wonder why I can only find these in Taiwan for 3x the price... if at all.

    There is an inherent design conflict --- you leave it in direct sun (like the dashboard in your car) to charge and the battery cells are getting exposed to excessive heat damage while charging.

    Seems like another day at the offcie where the marketing department and the engineering department are not on speaking terms. Do I add on a Pelteir Cooling Module and have that rob all the charging ability? Or do I just forget the solar cells? Or do I just not tell the customers that it won't last?

    Are we attracting bees to honey? Or flies to that other stuff?

    The real value -- At $20, just buy it and never use the solar charger.

    The solar cells need to be on top to collect sunlight, so they can also provide shade to the batteries and other robot parts.

    The robot has a microcontroller so it can monitor the battery state and stop charging them when they are full. With a solar cell that provides less current than the robot draws when running even that not necessary. Just have the robot start up.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2014-07-20 08:54
    I try to put the batteries low for a low center of gravity and to keep them cool as well. So these are awkward at best.
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