There are links to many very usable WIKIs of different used mods:
Mekanism - HERE
IndustrialCraft 2 - HERE
Tinker's construct - HERE
MC heli - HERE
Jurassic craft - HERE
Galacticraft - HERE
BiomesOPlenty - HERE
Aether - HERE
Traincraft - HERE
Twilight Forest - HERE
Computercraft - HERE (I also suggest finding on forums)
Conversion rate for energy actually is 1 EU = 20 J