TL;DR
Allow fluid type EnergySource in equipment.What ?
Why ?
after playing with gun equipment(https://mods.factorio.com/mod/GunEquipment)and I just came up with mutiple idae taht make all weapon can be place into grid and have different reloading equipment,
by having fluid energy source will be enough to describe all thing in terms of bar,then it even can use different to show different color and text.
(like yellow ammo shown in yellow,pirecing ammo shown in red)
if I make a radar equipment in grid,I will be able use the bar as the loading cooldown,
if I make a handcrafting support module(have handcrafting speed faster when active),I will be able to show what state it is in.
(green->idle,yellow->working,red->overheated)
if I make a combat bot radio equipment(increase the following_robot_count),I can show how much bot capacity it currently used.
