suitable battery selection

Discussion in 'General Electronics Chat' started by iknaite, May 30, 2012.

  1. iknaite

    Thread Starter New Member

    May 23, 2012
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    Which 9v battery is better to drain the current about 300mA and voltage 5v? Duracell(Alkaline or Lithium) OR Panosonic(Alkaline or Lithium).
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    A capacity of a typical 9V battery is about 500mAh.
    Hence you will get about one hour of operation at a current drain of 300mA.
     
  3. iknaite

    Thread Starter New Member

    May 23, 2012
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    Thanks for ur reply,

    How to connect 9v battery to the microcontroller with regulator? Operating voltage of microcontroller is 3.3v.
    Please explain with circuit diagram.
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Use a 3.3v LDO voltage regulator.
     
  5. crutschow

    Expert

    Mar 14, 2008
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    A lithium battery will last longer than an alkaline but they are significantly more expensive.

    If you want long battery life for the microcontroller then you should use a switching buck regulator, not a linear regulator.

    If you use a linear regulator, three AA or AAA batteries will give you much longer life than a 9V.
     
    #12 likes this.
  6. bountyhunter

    Well-Known Member

    Sep 7, 2009
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  7. MrChips

    Moderator

    Oct 2, 2009
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    In that case you don't need a voltage regulator.
     
  8. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    Maybe, maybe not: the full charge voltage is 4.2V and the uP might not be able to handle that. Depends on the specs.
     
  9. iknaite

    Thread Starter New Member

    May 23, 2012
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    How to know the mAh rating of the Duracell 9v lithium battery?
     
  10. Audioguru

    New Member

    Dec 20, 2007
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    The datasheet on Duracell's website is very brief and has only one page. It does not say the capacity but shows a graph with a load of 50mA when the voltage starts at 8V and it drops to 7V in about 15 hours when it is almost dead. It has a PTC current-limiter which might prevent a current as high as 300mA.

    Energizer has a detailed datasheet for their 9V Lithium battery. Its voltage starts at 7.5V when its load is 500mA and drops to 7V in a little over one hour. In 1.4 hours the voltage is 6V and is dropping fast. Its maximum allowed current is 1000mA.
     
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