Your iPod nano has a $20 Li-Poly battery and your mote has a $0.20 AA
battery.  You're expecting identical performance????

-Joe

On 5/25/06, Chang Li <[EMAIL PROTECTED]> wrote:
I bought 8 AA batteries in the 1 dollar store. It only run 20 hours then the
leds
were dim. The voltage of the battery was under 2.0v. 18.2+mA is the current
consumption of CC 2420. There are MSP430 and Flash Memory as well as
othere ICs. I am wondering why have tested the current of 50 to 60 mA with
Rx and Tx enabled.

My iPod nano with LCD,1GB Flash, and Li-Poly battery can even run 14 hours.
I have expected that a mote should consume much less power than an iPod.
Some special programming skills may be required to save power of motes.

Chang

>6 days sounds about right.  When the radio is turned on and simply
> listening, it is consuming an average of 18.2+ mA - your 18.8 mA sounds
> accurate.  I measured it to be about 437.4 mAh/day.  With 1500 mAh
> batteries
> and those measurements, you're looking at about 3-4 days lifetime.
>
> Duty cycle the radio and you'll get many more days.  At 0.23% duty cycle
> with a cc2420 radio duty cycle period of 10 seconds, the lifetime of a
> tmote
> should be about 300+ days at 1500 mAh.
>
> Keep in mind that batteries are rarely what they say they are - 1500 mAh
> is
> the minimum guaranteed by the manufacturer.  Many batteries can
> potentially
> last much longer than what they're rated, especially depending on the
> environment and type of battery.
>
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of
> [EMAIL PROTECTED]
> Sent: Wednesday, May 24, 2006 9:27 PM
> To: [email protected]
> Subject: [Tinyos-help] tmote batteries lifetime
>
>
>
> I have one doubt about tmote batteries duration. I'm using tmote sky
> with 2 AA 1500 mhA batteries. If i not use any LPL on cc2420 the rx
> consumption would be about 18.8m A. So the  energy in one second would be
> E = 3V . 18.8 mA . 1 s = 56.4 mJ
>
> I have read the joe paper about b-mac where says that
> t(s )= Cbatt . V.60 . 60 / E
>
> It gives me about 6 days of bateries duration. Would it be right? I
> suposse that radio is always in rx mode waiting... Am I wrong?
> thanks a lot
>
>
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