Good idea, i have a question though, how is this working with other mods? i am especially interested in Angels+Bobmod?

I've not yet looked into that. I don't think it's conflicting.
If any mod you're using adds entities that should cost electric engine units, thats very easy to make youreself (look in the config.lua).
Bobs and Angels are so popular that I was already planning to look into it.

Ok. Looked into the bob's assambling machines (4, 5 and 6) and inserters. The inserters all seem to cost the electric inserter so I don't think you have to add a basic electric engine unit. For the assambling machines, if they should cost engines I think that should have been normal electric engine units.

You might want to add a basic electric engine unit to the "electronics-machine-1" from bob's assambling machines.

I've been very busy with school, but now I've finally made some small patches with bob's mods.