Battery dosent work.

Discussion in 'Troubleshooting' started by TheJRT, Dec 23, 2013.

  1. TheJRT

    TheJRT New Member

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    So the Udoo boots fine when it's connected to the power supply but when I use the provided external battery with 2 AA batteries the green light doesn't turn on. I tried different batteries but nothing. For my project it's vital that the UDOO works on batteries. Any help?
     
  2. venkatbo

    venkatbo Member

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    As evident from many sources, the ext psu needs to be rated 12v providing at least 2Amps+ - definitely not what 2 AA (~3v) can provide. Min is at least 6V I think.
     
  3. TheJRT

    TheJRT New Member

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    So wait the Udoo team sends an external battery thingy that dosent actually work?

    What could work as an external battery?

    Would any emergency phone external battery work?

    Merry Christmas Btw :D
     
  4. EBrown

    EBrown New Member

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    Well considering the Udoo requires 6V to 15V of power, while the recommended is 12V (so we will use 12V for all of our assumptions in this post), and AA batteries are 1.5V (meaning two of them are 3V), I'm not surprised it doesn't boot.

    I would use 20 D-Cell batteries. Eight of them in serial, parallel with each other. (You will want Alkaline Long-Life batteries.)

    Based upon the findings in the post viewtopic.php?f=21&t=104#p1082 you could make some basic predictions on battery life.

    The Udoo draws .5A max according to those findings, at 12V. The D-Cell batteries I recommended supply roughly 17,000mAh (based on data provided at the following URL: http://www.allaboutbatteries.com/Energy-tables.html). Now, 10 AAA, AA, C, or D batteries in serial provide around 12V give or take a small amount. (Typically 5%, which is negligable.) Now at 17,000mAh (34,000mAh in parallel), you can provide 34 amperes for 1 hour, or 1 ampere for 34 hours. (Basically 34=tA, where t is in hours and A is in amperes.) So, with the Udoo requiring .5A max (approx.), we can assume that it will last for 72 hours on the 20 D-Cell batteries. Base Idle will allow the Udoo to last around 170 hours. (Again, according to the research done by DracoLlasa.)

    Really it doesn't matter what parallel/serial combination you use with the 20 batteries, so long as the minimum voltage is 6V, it will last for 72-170 hours. (The laws of energy conservation keep this true.)

    So, 16 D-Cell batteries at roughly $28/8-pack (where I live at least) will cost $70 and last 3 to 7 days. Unfortunately there aren't a lot of alternatives to solve this problem. (Even a typical car battery won't help much, they are usually 45-70Ah. Which means your Udoo would last 90 to 140 hours at max load, and 225 to 350 hours at idle.) Now, if you are running it in a car you would have better luck, as a car battery is constantly recharging while it's on (provided the alternator is good.) So assuming it's at idle the entire time it's off in the car while it's not running, you should get 9 to 14.5 days of life out of it.

    This same scenario, played out with typical NiCd AA batteries, provide roughly 5.88% of the length of time D-Cells would provide (4 hours max load, 10 hours idle). I recommend D-Cells as I assume you want more time than that.

    Note: These are not exact figures. These are simply mathematical assumptions with a perfect world being assumed, and some rounding errors being created as well. Some of these estimates are conservative, some are just the opposite. However, they should be within a fairly small margin of error. Somewhere from 5% to 10%. (Rough guess.) These estimates are also assuming the data provided by http://www.allaboutbatteries.com/Energy-tables.html are correct, or even relatively close.

    Thanks,
    EBrown
     
  5. venkatbo

    venkatbo Member

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    I think that comp is meant for an RTC (instead of a 3V coin cell). The RTC coin cells used in typical PC motherboards are rechargeable types, ensuring long life. But unsure if those attached to UDOO's can be recharged ;?)
     
  6. TheJRT

    TheJRT New Member

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    Wow such an amazing answer, I thank you sir!
    Now i have a truly great idea on how to power my Udoo. I will probably go for both an 10xAA battery solution to reduce weight and also for the 20 D batteries in case I need more energy.

    Once again I thank you for the time it took you,

    Merry Christmas

    Jrt
     
  7. TheJRT

    TheJRT New Member

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    No the only thing they sent was a battery holder, I used normal batteries.
     
  8. jdonavan

    jdonavan New Member

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    That battery connection is for the real time clock, not powering the board itself. If you want to power the board with batteries connect a barrel to your battery case and plug it in to the barrel jack.
     
  9. TheJRT

    TheJRT New Member

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    There is also another dc-in port to power it just behind the USB ports.
     
  10. EBrown

    EBrown New Member

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    Wanted to update:
    On some recent research (which I was conducting for a device for my cell phone), I discovered this item:

    http://www.amazon.com/EC-TECHNOLOGY-Ult ... roduct_top

    Basically it's a small battery, that is capable of storing an advertised 22.4Ah. This would give the Udoo 44.8 hours of use at max usage, at the advertised minimum. You should be able to get 44.8 hours to 119 hours of use out of it. The benefit to this setup is that it is live rechargable. (Plug it into power and let it charge and then go at it again.)

    Now you would need to make a few modifications to it in order to get 12V out of it. But it should be able to prove a fruitful device with the right configuration.

    And at $55 (right now, at least), you pay $2.46/Ah. You also get an advertised 500 full charge/discharge cycles.

    Again, with some math, that boils down to $0.005/Ah. (As with it advertising the 500 full charge/discharge cycles, that equates to 11,200Ah.)

    Provided all their advertisements are correct, and all the math is sound, you should be able to get 2.5 years of continuous use out of it minimum, provided you recharge it every 44.8 hours.

    Just thought I would pass this along.

    Note: Again, these are not exact figures. These are simply mathematical assumptions with a perfect world being assumed, and some rounding errors being created as well. Some of these estimates are conservative, some are just the opposite. However, they should be within a fairly small margin of error. Somewhere from 5% to 10%. (Rough guess.) These estimates are also assuming the data provided by http://www.allaboutbatteries.com/Energy-tables.html are correct, or even relatively close, as well as the advertised specifications for the advertised product are correct.

    Thanks,
    EBrown
     
  11. TheJRT

    TheJRT New Member

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    igniore this
     
  12. TheJRT

    TheJRT New Member

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    Thanks for keeping me informed. This battery seems a great alternative, especially at this price.
    Im really intrested in this.

    thanks again and have a nice day

    JRT

    P.s. if its fine for you we could ask the mods to pin this thread, it contains precious info that could help others with similar ideas.
     

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