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Using this power level indicator to measure a power supply voltage

  1. Apr 2, 2017 #1
    In this project, I am using the https://www.amazon.com/GoGreen-Powe...coding=UTF8&psc=1&refRID=GFTK6TYZSWGAMP5JS078
    as a power supply, but in my project, if my device shuts off suddenly without shutting off properly, it would require me to reboot the entire system as it wont work anymore.

    So I decided to use this power level indicator to let me know when the power was low
    "LM3914 10 Segment 5V 12V Battery Capacity Power Level LED Indicator Display Kits"

    Could I get a two way usb splitter that connects to the power supply, one that powers the device, and another to the power level indicator so that I could measure the battery level?

    Or would it be better if I measured through the batteries positive and negative ends directly?

    I noticed that although the output through the usb port from the power supply is 5 volts, it does use x6AA batteries wired in series to each other.
     
    Last edited by a moderator: May 8, 2017
  2. jcsd
  3. Apr 8, 2017 #2
    Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.
     
  4. Apr 10, 2017 #3

    rbelli1

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    Gold Member

    The LM3914 uses about 2.4mA by itself to say nothing of the LED's. That is a lot for a battery monitor for AA batteries. Does your project have any analog input capability? Can you use that to measure the battery voltage? Otherwise use a comparator or voltage monitor to sense the battery voltage (directly on the battery not the USB output). These are available in very low current versions.

    BoB
     
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