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Mean current calculation using energy trace CC430F6137

Fahad Said
Prodigy 130 points
Other Parts Discussed in Thread: MSP-FET, CC430F6137, ENERGYTRACE

Hello,

I would like to know how is the mean current calculated using energy trace tool. Is there a formula? When I use MSP-FET on CC430F6137 I get the mean, max and min current readings. see the pic below: Also, How is the battery life calculate? I looked at the mah for CR2032 but with the mean current drawn i do not get exactly the lifetime indicated in the pic below. Is the current data saved in a file which I could see all the current values for the duration run of energy trace tool.

Thanks

Fahad 

  • 0
    TI__Genius 16165 points
    Fahad,

    The Battery Life is calculated based on the Energy/second rather than the current mean. EnergyTrace tool is designed to accurately capture Energy and current is back-calculated based on the change in the energy consumption. The mean that the current is calculated and averaged to reduce spikes as it plots. If you connect a current meter on the system, you should read the average (or somewhat close) to ~1.8mA. It is also seeing a maximum current consumption of 14.081mA probably due to the radio activity.

    The way you calculate the battery life is the following:

    1. Take Energy/30sec = 161.86mJ/30s = 5.395mJ/s. This is your energy being drawn out of your battery every second.
    2. CR2032 battery is assumed to be around 220mAh here. You need to convert this to Energy (E=C*V). This means you have approximately a total of 2,376,000mJ (220mAh * 60 * 60 * 3V).
    3. Take 2,376,000mJ / 5.395mJ/s = 440,380 seconds = 5.1 days.

    Hope this helps.

    Regards,
    William
  • 0 in reply to William Goh
    Prodigy 130 points
    Thanks William. That really helps

    Fahad

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