I recently added the Xbee Xtend 900 to the APM. Prior to that with the Xbee Pro 900, everything was OK aside from poor range with the unit.
I believe that two recent crashes involved a brownout on the APM sometime after sending commands via the Xtend. Simply using it for receiving data seems to be OK. I had powered it via the four pins off the APM, but the amperage at 1W (5v) is supposedly 730mAh.
The next level down is 500mw (Input: 3-5v, 500mA). Question is... what can the APM support in terms of current draw/voltage for telemetry? Is this too high?
I've been trying to power it via an external battery, but the breakout board I have seems to be finicky. I can't get any data to transmit when I hook up a 5v BEC directly to the Xbee board. Plugging in to the APM, it works immediately.
The documentation mentions that the regulator on the Ardupilot board can go to 1 amp, but it also mentions a resettable fuse of 500ma, which protects the board only (not involved with the power bus operating servos).
I would guess that you would trip the resettable fuse hanging anything off the board that needs anything close to 500ma.
Thanks- that confirms my findings after setting it to 100mw (~300mA). Everything's operating fine.
I am wondering why the Xbee doesn't TX/RX when powered from an external battery though. Any thoughts on that?
Do you have a common ground (ground of ardupilot is ground of xbee), even with the external battery?
No- the xbee is grounding to the battery
I'm no expert at all, but the signal levels are with respect to a ground .. so there must be 100% connectivity between external battery ground, xbee board ground, and ardupilot ground. Someone correct me if I'm wrong.
Nope. Spot on! All grounds must be common.
I am facing a some what similar problem. I have same xbee. powered from input rail. my ubec connected to input got hot and almost all its black ground wire burnt. is it that xbee is draining power.??
That sounds like a short circuit to me. Red wire in the middle, yeah?