XBee Carrier - association LED flashes rapidly on battery

Good evening.

I purchased four Grove XBee Carrier boards to do some prototyping work and while the XBee (Digimesh 2.4 S2C) work fine from USB power it won’t boot up under battery power (RX/TX lights solid red, ASSOC flashes rapidly). Interestingly powering it by USB then disconnecting USB allows the XBee to continue to operate on battery.

Has anyone seen this behaviour before?



PS - I wrote a full page analysis with measurements etc (took 2 hours) but the internet ate it. Arrrgh!

Good morning:

When the XBEE boots up ,it needs more current than normal working condition.I’m afriad that your battery can not supply this system’s boot up current(Digimesh 2.4 S2C also need more current when it goes to work).AS you found that( powering it by USB then disconnecting USB allows the XBee to continue to operate on battery) .When the system boots up instant by using battery ,the battery’s voltage will decrease,and cause boot up fail.When the system has already boot up ,XBEE can operate on battery.

Hi Hong.

Thanks for the response.

I measured the voltage on pin 1 of the XBee with an oscilloscope and it comes up at the same rate whether running off battery or USB. The voltage droops 1V for ~5uS at the battery when the power switch is turned, then returns to a steady level; there is no droop at pin 1 of the XBee Digimesh 2.4 S2C. If the battery can’t provide the energy required I’d expect to see a longer or sustained droop.

The current draw for the XBee Digimesh 2.4 S2C is 33mA/28mA. This is similar to that 34.5mA/18.1m of the RFBee which, as stated on the XBee Carrier wiki is compatible with the XBee Carrier. It should work.

Dear All,

We are facing the same problem, your posts explained the reason behind this problem. Now is there a solution for it?

We tried batteries up to 6V batteries and other batteries with 3000 mAh batteries (twice the battery capacity that comes with the WSN kit) but with no luck.

We want a solution such that the Xbee boots from the battery with intervention since we want to use it in an outdoor application.