Correct however unless I am mistaken you only have one output port to work with in terms of where the battery can go in for each machine as such you need to add to and pull from the same slot BC pipes can't do that, however I haven't actually tried it so it may be able to read it from the side not sure however TBH not sure if a CC turtle could read it even from another side, I suppose a BC gate on the side of the device pulsing a RP 2 filter and retriever though that would be pretty much the same as using a computer and a computer is easy to make relatively early game only some iron and stone as opposed to needing the infrastructure to create the gates (I guess you would also need at least an iron gate.
For charging up a power system, yes, I believe you are correct. Otherwise, when charging up a battery, you can pull it from the sides. It may be the same for when charging up a system, which would mean a setup of enderchests, filters, a power storage block, and a timer should work perfectly fine for both situations.
Obviously the turtles are still not that useful for the no-cables, batteries-only idea.
You could use turtles and ender chests to move batteries without needing tubes, which is what I do, although it seems pretty bloody silly to have one for EACH machine instead of just having one for each set of machines and then wire them together.
And yeah, tesseracts can work. I've yet to get bitten by the ender chest bug in regards to my battery moving turtles, though.
