Unfortunately, there is nothing I can do about this. No accumulator type entity can charge inside a factorissimo building because the power is being provided from an accumulator inside the building.
It is the same reason your power poles will not charge at night if you use purely accumulators.
isn't there a priority system for power or did the devs took that out? i remember that there was a mod with priority steam engines,
or maybe you could do it like https://mods.factorio.com/mod/accumulator-wagon
converting energy into a internal liquid and then use that instead?
Definitely not going to do the internal liquid thing, but I should revisit the power priority system in case the devs added any new levels.