what high current sensor can I use it to measure a current in an electric vehicle battery?

Discussion in 'Automotive Electronics' started by anahila, Mar 16, 2016.

  1. anahila

    Thread Starter New Member

    Mar 16, 2016
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    Hello, I'm looking for a high current sensor which be able to measure 500A (DC measurement) in the ambient temperature range between -40°C to 80°C with high accuracy. I want this sensor to measure a current in an electric vehicle battery.
    I made a research and I found that I can use a shunt resistor or Hall effect sensor or fluxgate sensor. I thought to use shunt resistor with an isolation amplifier to ensure galvanic isolation. Is this solution better than other method of measurement? or it's better to use Hall effect sensor or fluxgate sensor since they ensure galvanic isolation ?
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Shunts #1 do NOT do well in high ambients and #2 are heaters that WILL dissipate heat thus raising the ambient.
    IMO.. shunts are "old tech" that really should be used anymore..

    Hall effect is the way to go.. (probably)

    Now define "high accuracy"..
    +/- 2%?
    +/- .1 amp?
    +/- 5 Amp?
    something else?

    I've used this for up to 800 Amps in the past..
    http://www.melexis.com/Current-Sensors/IMC-Hall-Current-Sensor-ICs/CSA-1V-614.aspx
     
    Last edited: Mar 16, 2016
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  4. anahila

    Thread Starter New Member

    Mar 16, 2016
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    there is the specification of the sensor that I'm looking for:
    The current sensor must be able to measure current gradients up to 125 A/ms (di/dt).
    - The current sensor must meet the following accuracy requirements in the ambient temperature range between -20°C to +60°C
    • -3 A < I < +3 A: ±20 mA
    • -500 A < I ≤ -3 A & 3A ≤ I < +500 A: ± 0.75%
    • -1000 A < I ≤ -500 A & +500 A ≤ I < +1000 A: ± 5% (Full functionality and no damage of the sensor over a duration of 2 seconds)
    • -2000 A < I ≤ -1000 A & +1000 A ≤ I < +2000 A: ± 7.5% (Full functionality and no damage of the sensor over a duration of 1 second)
     
  5. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    I've used LEM hall sensors up to 200 A with no problems. I know they make larger ones but I've never needed to look into them. -40 to +80 is a lot, and my experience with hall sensors is that they do drift with temperature. You might have to have some kind of correction loop.

    Ultracapacitor bank on a bus?

    ak
     
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  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Hall sensor is better: provides isolation, plus doesn't generate heat like a shunt would.
     
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