I need 220v to 3.6v 3700mAH transformer

Discussion in 'Power Electronics' started by kbaraka, Aug 16, 2016.

  1. kbaraka

    Thread Starter New Member

    Aug 16, 2016
    4
    0
    Dear All:
    I have digital water meter which operated by AA battery with the specification:

    · Compliant to IEC 86-4 safety and EN 50020 intrinsic safety standard

    · UL recognised (file number MH28717)

    · IEC code of battery is CR14505

    · Non flammable electrolyte

    · Available in AA standard size

    · Nominal capacity of 2.70Ah

    · Nominal voltage of 3.6V

    · Operating temperature range -65°C to 85°C

    · Continuous current of 40mA

    · Typical weight is 19g

    I need to replace this battery by 220v to 3.6v 3700mAH transformer. Is there any ideas to do that? Can I make any changes to any transformer or charger found today in the market?\
    Regards......
     
  2. #12

    Expert

    Nov 30, 2010
    16,248
    6,745
  3. kbaraka

    Thread Starter New Member

    Aug 16, 2016
    4
    0
  4. #12

    Expert

    Nov 30, 2010
    16,248
    6,745
    Your battery is not labeled 2.7 amps. It contains 2.7 AMP-HOURS when it is new and fully charged.
    There is no such thing as an amp-hour transformer.
    There is no such thing as a DC transformer.
    A power supply you leave plugged in forever contains infinity number of amp hours.
    These have nothing to do with your needs.

    You need 3.6 volts capable of at least 0.04 amps.
    Not 2.7 amps. Not 2.2 amps. Not 18.67 amps. Not 1.32 amps.
    0.04 amps.
    When you leave it plugged in for 10 hours, it will deliver 0.4 amp-hours.
    If you leave it plugged in forever, it will produce infinity amp-hours.

    Summary: 3.6 volts, 0.04 amps minimum.
     
  5. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,880
    371
    The battery is 2.7Ah Ampere hours), the power supply is 2.2A (Amperes). These two numbers are not measuring the same thing.
    The 2.2A means that the power supply can supply a current up to 2.2 Amperes and it will do this forever.
    The 2.7Ah for the battery means that, for example, the battery will supply 0.1 Ampere for 27 hours before it is flat. You multiply the current in amperes by the time in hours that current has been flowing to get the number of Ampere hours that has been supplied.
     
  6. kbaraka

    Thread Starter New Member

    Aug 16, 2016
    4
    0
    Thank you again for your help and sorry for the misunderstanding. I will go and buy it. Thanks.
     
  7. kbaraka

    Thread Starter New Member

    Aug 16, 2016
    4
    0
    Thanks and I wish you all the best.
     
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