Hello,
I found some issues with the coal generator:

1. The internal energy cell is full, but the generator absorb coal to produce wasted energy.
   (No Item is in the Item slot and no cable/machine is connected)

2.Wrong tooltips (Power gen 80 <-> 60 ?)

MC 1.12.2
Forge 2515
RF Tools 7.12
RF Tools Dim 5.05

yes that's intended. You have to make sure you stop feeding charcoal/coal or make sure to pump the power out