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68-Cent Powerbank - Page 2 — Parallax Forums

68-Cent Powerbank

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  • PublisonPublison Posts: 12,366
    edited 2016-02-07 23:00
    Used my Radio Shack,(http://digitalenergyworld.com/) 18650 2000 mAh) ) batteries to recharge two phones and an HP stream 7.

    This is a protected battery that I modified the bay to accept it in my previous post.
    The battery took two charges to external devices , and two recharges.

    Life is good.
  • ercoerco Posts: 20,256
    Publison wrote: »
    Life is good.

    Excellent news.

    We are so easily amused.

  • ercoerco Posts: 20,256
    My 68-cent yellow Powerbanks arrived today, the one I tested works just fine. Case and door are glueable HIPS, hooray, will get a simple robot going. The removable door is white. Seemed odd at first, but I suppose since they come in opaque black also, the door needs to be translucent white to let the red charging LED and the blue discharging LED shine through. FYI the door is a nice tight one-time snap, but it can be removed with a screwdriver or hobby knife.

    A foot-long USB-micro cable is included, which appears to be for charging only, no data connection. Plus a keychain ring. How in the heck can they sell and free ship that for 68 cents?

  • Publison wrote: »
    Used my Radio Shack,(http://digitalenergyworld.com/) 18650 2000 mAh) ) batteries to recharge two phones and an HP stream 7.

    This is a protected battery that I modified the bay to accept it in my previous post.
    The battery took two charges to external devices , and two recharges.

    Life is good.

    Hello!
    These are the same ones that I was curious if they'd work in either of the two battery boxes that Parallax sells, correct?

    I finally found a place who sells 18650 battery holders, Tinkersphere Single 18650 battery holder it happens that like all such holders they are being held securely.

    On an equally strange footing, Sparkfun also sells 18650 batteries and holders, both single and dual, also individual contacts. And get this, since they are using the same chemistry inside as the classic flat pack battery, the recommended charger is any of the ones they sell for those flat pack ones. But for those that we both used, I'd use the charger that that came with one set.
    Incidentally erco your robot was last seen boarding the Staten Island ferry.
  • PublisonPublison Posts: 12,366
    edited 2016-02-09 15:29
    Publison wrote: »
    Used my Radio Shack,(http://digitalenergyworld.com/) 18650 2000 mAh) ) batteries to recharge two phones and an HP stream 7.

    This is a protected battery that I modified the bay to accept it in my previous post.
    The battery took two charges to external devices , and two recharges.

    Life is good.

    Hello!
    These are the same ones that I was curious if they'd work in either of the two battery boxes that Parallax sells, correct?

    I am using them in the 28988 Power Pack. They do deform the plastic holders a tad at the ends, but they are never coming out! :) May void the warranty.

  • Publison wrote: »
    Publison wrote: »
    Used my Radio Shack,(http://digitalenergyworld.com/) 18650 2000 mAh) ) batteries to recharge two phones and an HP stream 7.

    This is a protected battery that I modified the bay to accept it in my previous post.
    The battery took two charges to external devices , and two recharges.

    Life is good.

    Hello!
    These are the same ones that I was curious if they'd work in either of the two battery boxes that Parallax sells, correct?

    I am using them in the 28988 Power Pack. They do deform the plastic holders a tad at the ends, but they are never coming out! :) May void the warranty.

    I see. That's the small guy. Would fit directly into the Boe Bot's body. Would those same ones fit into the bigger relative to the one you describe, that's this fellow, 28989 Or am I (much) better off buying replacements directly from Parallax?
    Oh and erco does your robot know anyone in NJ? He's exploring the state after somehow getting there from Staten Island.
  • ercoerco Posts: 20,256
    From both the "Ask and it shall be given" and "Now I feel Dumb" departments:

    I was just thinking that a quick improvement to these powerbanks would be a built-in LED flashlight...

    Well DUH, there is, on the 2-cell types. In addition to the red & blue SMT LEDs which shine through a clear light pipe to indicate charging/discharging, there's a clear 5mm LED shining out by the USB ports. It never lit up, I wondered what it was for, or possibly defective. But today I accidentally pressed on the clear light pipe indicator and Voila, it toggles the white LED on.

    Am I the first or last guy to discover that?

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  • You say banana, I say banana-bot!!
  • erco wrote: »
    From both the "Ask and it shall be given" and "Now I feel Dumb" departments:

    I was just thinking that a quick improvement to these powerbanks would be a built-in LED flashlight...

    Well DUH, there is, on the 2-cell types. In addition to the red & blue SMT LEDs which shine through a clear light pipe to indicate charging/discharging, there's a clear 5mm LED shining out by the USB ports. It never lit up, I wondered what it was for, or possibly defective. But today I accidentally pressed on the clear light pipe indicator and Voila, it toggles the white LED on.

    Am I the first or last guy to discover that?
    Probably. But then I did arrange it.
    ----
    However what is your robot doing now getting off a bus right near your place erco? And he's dragging a footlocker that's four times his size behind him.
  • ?
    Where's the purple raspberry?

    I'm happy with the TP4056 Li-Po modules I got for .77 each recently.
    Since most of the 18650's all seem to be expensive or resleeved salvage junk I'm playing with small LI 40B's which I found somewhere for $2/ea. They seem to be legit at ~1100 mah.

  • ercoerco Posts: 20,256
    Yeah, I'm not sure what my $1 GTF 9900 mAh 18650's are really putting out. :)
  • ercoerco Posts: 20,256
    edited 2016-02-21 14:43
    So many jokes, so little time.

    Is that a Banana Powerbank in your pocket?

    No that's a chili pepper USB hub in my pocket.

    I'd get a charge out of getting these kids together.

    All that power will go to their heads.

    No, I can see it going one of four ways.
  • ercoerco Posts: 20,256
    edited 2016-03-12 02:04
    Finally gonna build a little robot using one of these Powerbanks as a chassis. I removed the USB socket and enlarged that rectangular hole to fit a small DPDT switch. Need to switch both 5V out and battery + out since I plan to run servos at 3.7V. Can't just put a SPST switch to disconnect the battery, it needs to remain connected to the PCB for charging in the off position.

    I mounted a 6x2 header for 3 servos plus 5V power/ground lines for the processor & sensors. Looks pretty nice IMO. I flattened the positive battery contact in a vice, that makes the battery fit better (way too tight previously). Pics attached. Here are a few fun facts I learned in testing this ONE module today:

    1) The internal blue LED indicating "I detect a load and I'm outputting 5V now" only comes on above 55 mA, but it's still producing 5V even if the LED is off. The LED stays on as long as that minimum current is drawn, and stays on for over 10 seconds after the current drops, even to zero. Regulation is only fair, dropping down to ~4.85V at ~300 mA.

    2) The internal red LED comes on when charging through the micro USB jack. The module's 5V output is switched off when charging. Flashing means charging, also no battery present. Steady red means fully charged.

    I anticipate a lot of noise in the 5V output, which hopefully can be tamed with some filter caps. I want to use a 433 Mhz radio control module in this one, and I know those don't deal with noise very well.

    BTW there's some good info on those modules at http://www.romanblack.com/RF/cheapRFmodules.htm
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  • Never had anything but grief with those 433 mHz modules. Once I got NodeMCU for the ESP8266 working I never looked back and have done dozens of wireless projects since, some of them in regular use in industrial environments.
  • ercoerco Posts: 20,256
    edited 2016-03-27 18:28
    $1.54 for the deuce: http://www.ebay.com/itm/5600mAh-5V-USB-Power-Bank-TUSI-Case-18650-Battery-Charger-DIY-Box-For-Cell-Phone-/281753986575

    This styrene Powerbank holds two 18650 cells in parallel and has a single white LED "flashlight" built in. Same price for all colors, where the single-cell life form in my OP was about a mystery pricing scheme where only the yellow unit was cheap.
  • Reviving this thread for two updates:
    1) 50-cent power bank (aliexpress link here) ... this is a sale price, so it will change over time
    2) Different chip (HT4928S) has a cool feature - input/output are connected!

    Why is this a feature? Imagine that the battery is running low. Plug in the charger and keep on going.

    I found this quite by accident and it saves me a bit of grief. I was probing the circuit in order to determine the easiest way to implement a circuit that would automatically select either the 5V from the battery boost or the 5V from the charger input.

    The application that I had in mind is a portable bluetooth speaker. I don't want the audio to stop just because I need to charge the battery! Non-stop rocking appears to be possible. I have not pushed limits of this configuration yet, just a simple validation test (phone plugged into the power bank, power bank plugged into a charger).
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