[Tinyos-help] Battery Power measurement

[Jacob Sorber]

A word of caution.  If you are using battery voltage to estimate residual
energy, make sure you look at the discharge curve for your particular
battery.  It will not be linear, and it will depend on how much current you
are drawing.  For example, using a GPS receiver that draws 40-80mA is going
to cause your voltage to dip a little.  Also, if the batteries are being
recharged, the entire curve will be shifted up--the amount of current is
flowing into the battery will determine how much it shifts.  Typically if
you need really accurate estimates, voltage is probably not the measure you
want.  Rather, you should look at using some kind of fuel guage IC (e.g. the
DS2770 or DS2751 from Maxim/Dallas) which if used properly can give you a
much more accurate measure of how much energy you are consuming.  If you
just need a ballpark estimate, then use voltage and then use a model of your
battery to map the voltage reading to residual energy.

Good luck,

Jacob Sorber


On 10/9/06, Munaretto, Daniel <munaretto at docomolab-euro.com> wrote:
>
> Dear Wu,
>     i'm interesting in the same question. I checked Voltage.nc and
> VoltageM.nc.
> How can i get the voltage value from async event result_t ADC.dataReady(data),
> specified in VoltageM.nc,  to my main program (BcastM.nc)?
>
>         -----Original Message-----
>         From: Wu Nick [mailto:wgd8700 at hotmail.com]
>         Sent: Sat 10/7/2006 4:46 PM
>         To: singhals.sumit at gmail.com; tinyos-help at Millennium.Berkeley.EDU
>         Cc:
>         Subject: RE: [Tinyos-help] Battery Power measurement
>
>
>
>         Check the component "Voltage.nc" , then call ADCbatt.dataReady
> (uint16_t)
>         to get the ADC_Count. Also see  Crossbow, MPR-MIB Users Manual
> (page 25)
>         for detail.
>
>         Best regards,
>         Wu
>
>
>         >From: "Sumit Gupta" <singhals.sumit at gmail.com>
>         >To: tinyos-help at Millennium.Berkeley.EDU
>         >Subject: [Tinyos-help] Battery Power measurement
>         >Date: Fri, 6 Oct 2006 18:47:53 -0500
>         >
>         >hi,
>         >
>         >I am wondering how we can measure the remaining nodes' battery
> power
>         >and
>         >store them at base stations. I am using telosb motes. Please
> advice.
>         >
>         >Regards,
>         >Sumit
>
>
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