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: tinyos-help@Millennium.Berkeley.EDU
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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