Does anyone have any suggestions on how to increase the battery run time when running an arduino with an Xbee module? I am getting about 10-12 hours right now off of a 9V battery.
The application is used at a sporting event to transmit penalty times to the computer so putting the Arduino in sleep mode won't work unless it can wake up and transmit the penalty time in less than a second or two.
Unless there is a weight penalty, I'd run it off a 9V AA pack (6 cells -> 9V alkaline = 7.5V NiMH). The cells in a Snap-Top 9V are pretty tiny and low capacity at 625 mAh. Some experimentation and duration numbers available on this website. The best times were running the Arduino with a NiMH pack using 2500mAh cells. He also ran tests on XBee standalone power.
http://www.faludi.com/projects/arduino-and-xbee-battery-test-results/
I wish I could but, I can't use rechargable batteries because if someone leaves the unit on overnight by mistake, they can't hold up the competition waiting for it to charge.
How about carrying a spare? Or hook it up to a 12v car battery.
You can running an arduino with an Xbee module with 2 AA battery with the step up 5V converter.
this will provide 5V 100mA
If you need higher current, you can get this which provide 5V 400mA
AA battery have higher capacity then the 9V battery.
The arduino is pretty power hungry itself (30mA or something significant). You can dial down the clock frequency if you don't need the performance and get it down to 5-10mA. Search on the forum for details.
Chris
If you use a 8Mhz 3v chip like in the arduino pro the current is very low. You can sleep the arduino and the xbee and quickly wake them up for transmission. I have a remote data logger running on 2 AA cells waking a few times a day and getting 15K transmissions on one set of batteries.
You can 'pin sleep' the xbee to turn it off. The current drain should be about .04ma sleeping, 4ma processing your data and 50ma transmitting. A cr123a 1300ma hr lithium camera battery should last you a season.
Sounds like a neat project.
The zigbee chip (ember 250) inside the XBee uses a fair amount of power. As with any radio, the solution is to not turn on the radio. I've not used the Digi module, just the Ember one inside, and you can program it to be more power selective. Depends a lot on your application.