It may have just been a thing with the Magmatic Dynamo in 1.6, as that is all I ever used. But if they didn't have lava in them, their internal buffer wouldn't drain... at least I didn't think they did, I can't remember, but I am sure that was the case.No they weren't. @Ashendale said all the power drained, and I had first-hand experience as well. They drained fully. Unless it was a later version, of course...