Stalker 2 power supply

Hello, I have not undersood the two power IN on stalker v2 must be used. For example if I power the SOLAR one my xBee module does not work at all. If I power on the LIPO_BAT using an AC-DC everything is ok. Why?
What are the max and min voltage values accepted for SOLAR and LIPO_BAT pins? Can I supply my stalker with 9v as I was used with my arduino uno?
Thanks in advance for your help.

Partially you may find the answer about the min and max voltage here: … alker_v2.0

If the Li-po accu is plugged in, the Stalker runs from accu. If you plug additionaly the solar panel and the light is sufficiant the energy from panel powers Stalker and charge the accu. Connecting the DC voltage via UART works in similar way - DC supply Stalker and charge the accu.