Solar panel to Motorola phone.

Discussion in 'General Electronics Chat' started by Wise Old Owl, Nov 17, 2013.

  1. Wise Old Owl

    Thread Starter New Member

    Nov 17, 2013
    I have a Motorola Atrix and stuck in one more year agreement. and have tried several over the counter Panels such as 1 amp 10 watt Goal Zero on a regulator and on a sunny day with the phone at 10 -20% it will not take a charge. Substituted a 1 amp 5 volt solar panel installed a protection diode and removed the regulator and the same thing happened - green fast flashing light or lots of beeping & no charge. Charges fine from the wall & charges fine from a 2 amp car charger. Wont accept a solar panel, reguardless of size, amps or watts. I have enough equipment to change the panels or add regulators. I am at a point where I can install and build any circuit but cannot figure out what is with the internal charge circuit that is causing all the fuss. How do you stop the phone from complaining?

    Looking for ideas here.
  2. bug13

    Senior Member

    Feb 13, 2012
    Your phone might looking for signal from your charger, maybe try pull up or pull down those two data line with a 10K resistor or something?
  3. Wise Old Owl

    Thread Starter New Member

    Nov 17, 2013
    What I did was cut a cord off the 12 charger it didn't appear to have a problem with - so there is only two wires going in... might make some sense to install a jack and a resistor.
  4. wayneh


    Sep 9, 2010
    I agree that the problem is almost certainly the lack of a proper voltage on the data pins. It's also possible that the phone tests the charger for higher current and, if the voltage sags too much, won't initiate full charging.

    If you cannot find the right voltage to use from someone else's experience, you have to experiment for yourself. Use a 100k linear pot between +5V and ground for each data pin, and connect the wipers (center pins) of the pots to the data pins. Experiment with different know positions and combinations. You may get lucky. If so, replace each pot with a 2-resistor voltage divider.