Charging 5 AA's with USB

Discussion in 'The Projects Forum' started by Crazy8, Mar 31, 2014.

  1. Crazy8

    Thread Starter New Member

    Mar 31, 2014
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    I think I am posting this in the right area, If not I apologize. Anyway I have just bought the Wouxun AA battery case so that I can power my KG-UV6D with AA if ever needed. Well I usually do my research before embarking on a project but I thought this one would be pretty straight forward. Now I am not so sure. So, what I have done was attached (epoxied) a micro USB port to the bottom of the Wouxun AA Battery case so that I could recharge the rechargeable batteries I will be putting into the case, via USB. Of course after drowning it in epoxy, did my other ideas and questions come up. For instance, could I attach an LED that only turns on when the USB is plugged in? What would I need to do that? How will I know when the batteries reach full charge? Knowing when the batteries reach full charge is the biggest one. I have next to no room to work with inside the case, I'm lucky to get the couple wires to squeeze in, and I don't want to make my case too bulky. Would I be able to add the needed components to this to do what I want? Take into consideration that I have my USB port already under a lot of epoxy, which will be sanded down to look nice. I also have little experience with building circuits and basic knowledge right now.

    Any help would be much appreciated.
     
  2. wayneh

    Expert

    Sep 9, 2010
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    USB is meant to supply a smart charger, not to directly charge batteries.

    How many cells do you have in your pack, four in series? What rechargeable chemistry do you hope to use? (nicad, LiMH, Li-ion?)

    Could you live with a charger that is external to the battery case, sort of an "in line" device between the USB power source and your battery pack?
     
  3. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Do you have a license to operate in the ham bands?
     
  4. Crazy8

    Thread Starter New Member

    Mar 31, 2014
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    Absolutely I do. I have a tech license and will be hopefully trying for my General Class license this year.
     
  5. Crazy8

    Thread Starter New Member

    Mar 31, 2014
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    Thats cool, my name is also Wayne and my last name also begins with H. :) Its 5 batteries in serial. I plan on using 2300mAh NiMH Energizer or Sanyo Eneloop XX. I guess if I had to, I could have a charger outside of the pack. What did you have in mind? I was just hoping to be able to build in charging functionality into the pack itself.
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,135
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    I think you should read this. Charging NiMH is not so simple.

    Charging a 6V pack with 5V from a USB power source will require a boost DC-DC converter, for one thing. The good news is that you can buy one of those off e-bay really cheap these days.
     
  7. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Congratulations. I have been licensed since the late 60's, and have really enjoyed it. 73
     
  8. Crazy8

    Thread Starter New Member

    Mar 31, 2014
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    Not to change the subject but I got it out of necessity a couple years ago. I have been doing Skywarn for about 5 years now and as of March 10, 2014 I have been appointed, by the ARRL, as ARES Emergency Coordinator for my county. So that's more or less the need for my general now. I have enjoyed ham radio very much and I am glad I got into it. So much has come from it and I have a lot of fun with it. Im KD0RVY btw. :)
     
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