Heyas Darlene7,
I don't own an e-power, but as I understand it, it's a 510 threaded device. 510 refers to the threads that the atty or carto attaches to. 14650 is a battery type, which one model of the e-power uses. Apples and oranges.
As for filling carts, I don't use them. I use cartos or drip. But, when I did use them, I'd fill the cart unti I could see
juice on top, poke an unbent paperclip or pin or something between the filler and the edge of the cart and wiggle it to get the
juice to settle into the filler, then repeat until the juice stopped soaking into the filler. Then use a bit of paper towel to soak up the extra juice so that the top of the filler looks "slushy", and not like a pool of liquid.
Hope this helps. Post any other questions here and we'll all be sure to climb over one another answering them
Maximillian the Moderately Mischievious