connecting 10ah to ipod

Discussion in 'General Electronics Chat' started by kytaez, Aug 13, 2014.

  1. kytaez

    Thread Starter New Member

    Aug 13, 2014
    Hello AAC people!! First post here. Hoping to clear something for myself and learn along the way.
    So I'm well into my boombox project and originally I was using my phone as a source. But now I got a iPod classic 120Gb that I'm intend to build-in flush into side of boombox. I'm using a 4 LiFePO4 cells with 10w solar panel for charging them.
    The question is: Is it safe to connect iPod directly to one of the 3.2v 10ah cells (removing the original 3.7v 580mah) ???
    Will it work?
    What the minimum voltage needed for iPod to function?
    What the maximum it will tolerate before going up in smoke?
    As the voltage does go up when battery charging (yet to be measured in full sun) worried to fry the iPod (learned the hard way with power amplifier)
    Any answers and suggestions is highly appreciated!! Cheers!
  2. bhvm

    Active Member

    Jul 16, 2009
    Having Higher AH does not matter. The voltage does. can you source the 3.7v Cells?

    Also, Lithium has VERY peculiar charging characteristic. I would NOT recommend you play with them. They can EXPLODE!

    My suggestion,
    1)get a Charge controller designed to charge 12v lead acid battery (get 10 or 15 Ah as you like)
    2) Get a Car charger for your Ipod that will use the 12v battery as source and keep the ipod internal battery charged.

    It will also be cheaper and more upgradeable ,Plus saves warranty on ipod.
  3. kytaez

    Thread Starter New Member

    Aug 13, 2014
    Cheers bhvm! My bad. I didn't gave enough detail on what I already got and my goals with this project.
    Efficiency, less weight and more efficiency!! :) The reason I'm using LiFePO4 cells (Headway 3.2v 10ah) is weight and safety. Got 4 of them in series to get my 12v needed for sound amplification (Amp6 from, for charge controller I use balancing 12V LifePO4 BMS (14.4V) 4 Cell 50A/120A.
    I can probably use a car charger for iPod 12v to 5v 1A. but it doesn't make sense buying one imho as I haven't got one. Plus it's increasing the weight again. IPod is second hand (no charger and not sure about battery state)
    If massive increase of battery capacity not hurting the old iPod I would love to get rid of original battery (iPod)
    Cheers for your quick reply. I will measure the voltage in full sun charging mode and probably post some pictures. Thanks again!
  4. kytaez

    Thread Starter New Member

    Aug 13, 2014
    Found some usable information on pin layout for iPod:
    Pins 19,20 FireWire 12vcd (+)
    Pins 29,30 FireWire ground (-)
    Connecting pin 21 to ground with a 1MOhm resistor does stop the ipod when power (i.e. Firewire-12V) is cut. Looks to be that when this pin is grounded it closes a switch so that on loss of power the Ipod shuts off.

    So I can probably connect it directly and leave the battery in....