[Tinyos-help] Battery voltage curves - Estimating battery lifetime from Voltage

[Mante Bos]

Hi,

I can read the voltage from my batteries and I can transform this  
output of the ADC to the appropriate voltage of my platform (micaz).

Now I would like to now of someone had some curves of the battery  
voltages of nodes while their are running typical sensorapplications.  
I know from the manual that my motes (micaz) have an operating voltage  
range of [2.7 - 3.6] V. From curves like this[1] I can estimate the  
remaining power of the battery.

   Now I would like to have status of my battery, indicating of it has  
a lot of power, has medium lifetime or runs out of power. Does anyone  
has experience with trying this?
Since the curves drops faster as it runs out of power, I suggest to  
keeping a history over time to decide in what stage it is. I guess  
that it is also important for my decision to know if my radio/sensors  
are on, because I would have a slightly greater voltage output. Has  
anyone tried this or please mail me back if you have some good  
suggestions.

I would like to give my motes different behaviours depending on the  
remaining energy of the mote, so it would be interesting to have more  
than a warning that my mote runs out of energy.

   Thanks in advance!

   Mante

Links:
------
[1] http://www.lipoly.de/modellbau/akkus/kokam/kokam2000hd04.gif

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