help with modified minty boost project

Discussion in 'The Projects Forum' started by lokeycmos, Jan 28, 2012.

  1. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    so im building the minty boost project here: (1st schematic on the page)

    http://www.ladyada.net/make/mintyboost/parts.html

    i want to put it in a project box with rechargeable battery pack and a jack to charge it from a wall wart. the IC has a max volt input of 5v. for batteries i have 12 duracell NiMH AA 2650mAH. not sure if i should go for 4.8v@7.95AH or 3.6v@10.6AH. the watt hours are the same. the trickle charging circuit im thinking of using is here(circuit #3): http://talkingelectronics.com/projects/ChargingNiMH/ChargingNiMH.html

    i included a hand drawing of what im thinking. i would like to hear feedback if this will work or if i need to change anything. i do need some help finding the correct voltage and amperage for the wall wart to use as well as resistor values to use in the trickle charger.
     
    • 001.jpg
      001.jpg
      File size:
      203.4 KB
      Views:
      24
    Last edited: Jan 28, 2012
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    I would Strongly suggest isolation between the wall power jack and the USB hub, if things go wrong, it could damage your computer.

    I'd suggest taking a look at the adafruit (I think that is who made it first) forums and ask the same question as well.

    It looks like you are simply trying to add more capacity to the minty boost circuit. As long as the input is the same voltage (3-4V, 2AA batteries, IIRC), 3-4V source with more capacity should work fine as a substitute.

    Going beyond the design parameters in any way could result in problems, so ask the designer of it, or see if somebody has already done similar on their forum, such as using 2 NiMH D size batteries.
     
  3. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    its not connecting to a computer, it is for charging usb devices and phones. i already posted on the adafruit forum. they wont help me because i didnt buy their kit. i built it from the schematic and digikey parts. i already know that i can use bigger batteries in parallel for more capacity, but im wondering about integrating a charger into the circuit to charge the niMH battery pack.
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Keep in mind that the parts chosen had thermal limits, voltage limits, and current limits, as long as you meet all of those, in every single component, you should be good to go if you get 5V out.
     
Loading...