Scenario Pic:

Beacons will be powered by the cell above OR below (OR neither OR both)
What's weird is that for beacons that share multiple networks, some of them get full power and run normally while some of them get ~10% power. I have re-created the situation in small scale to confirm, as well as to test with other entities I had in my pocket.
Beacons on small scale:

Since the right power pole is always connected, I would expect this beacon to be at full power.
I also had a roboport, lab, and AM1/2 in my pocket. Roboport and Lab function as expected, while the AM1 and 2's run at ~95% power.
Here is album of the tests I did. http://imgur.com/a/vjUNM
Thanks!