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 _______________________________________________ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help _______________________________________________ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
