All the Battery Box does (compared to my other GUIs) is limit the stacksize inside the Slot to 1, so if InvTweaks cannot handle this, it is on their Side.
I can even guess that they try to insert something into the same slot that is already at max capacity because of assuming the Item Stacksize is what matters, so it infinitely retries to insert the same Items into the same Slot forever, instead of maybe just trying it 64 times or so, which would still be laggy but it wouldn’t be infinite.