Portable phone charger running on batteries

Discussion in 'The Projects Forum' started by Rudy Melo, Jun 16, 2015.

  1. Rudy Melo

    Thread Starter New Member

    Jun 3, 2015
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    Hello, I am wondering if I can make a phone charger that has an output of 5.2V 1A and as efficient as possible running on batteries. I have 7805 voltage regulators and lm317's but when I use the 7805 with a 9v battery, it does not supply enough current to make my phone battery percentage go up...it just remains constant (I believe 300mA or so if I remember correctly). How can I go about making this? Any ideas? Thank you in advance
     
  2. #12

    Expert

    Nov 30, 2010
    16,298
    6,809
    It's the 9 volt battery that can't survive the needs. Pick a better battery.
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
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    A better battery, and a switch-mode regulator/converter for higher efficiency compared to a linear regulator.

    If it takes 4hours to charge your phone, the battery will have to supply 1A for 4h = 4Ah. I would use a 6V SLA, like this:

    [​IMG]

    Even bigger, if you want several phone charges before having to recharge the SLA.
     
  4. Rudy Melo

    Thread Starter New Member

    Jun 3, 2015
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    0
    Thanks for your responses. Would a buck converter be a "switch-mode regulator/converter?"
     
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Yes. Like this
     
  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Probably cheaper just to buy a portable charger for the phone. Google 'portable charger'. There are lots available.
     
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