I have used the xBee carrier with the solar panel and battery for several weeks and have made a couple observations. First the led for TX and RX are on even thought the USB cable is not connected. Current from the battery with the radio sleeping is about 3.3mA in this state.
If I plug in a usb cable (connected to a computer or power source) for a second or two then unplug it the TX and RX lights go out and the current from the battery drops to 1.2mA. This is a significant drop. Within a few minutes after the USB is unplugged the TX and RX lights usually come back on.
I looked at the schematic and think that if you were to use the 3V3OUT of the FT232R to power the TX RX led this issues would go away. I don’t see any reason not to use the 3V3OUT of the FT232R to supply the VCCIO pin either. When the USB was unplugged no power would be applied to any part of the FT232R.
The power light is always on when the device is operating. Perhaps a jumper could be installed.
Just some thoughts.