"One module takes ~4 seconds to cloak 160T of ship, and moving (at any speed) drains your cloak: If you are under 160T, it fills up faster than it drains and you'll slowly recloak while moving, at over 160T, it fills up slower than it drains and you slowly decloak while moving. You cloak when you bar is 50% full, and it starts to drain 400 e/s per module once you cloak. When at 100% and stationary, you don't drain energy as you're at 100% cloak and don't need to generate more.
Increasing cloak modules gives you another 160T that you can move around without decloaking. It's perfectly viable to have a ship with one module that weighs 320T, this would take 8s to cloak while stationary and stays cloaked for 4s while moving. Or a ship at 80T that re-cloaks in 2s after firing and takes 4s to cloak while moving. Or any combination of cloakers/tonnage, but as mass goes up, cloaking becomes less efficient, and as modules go up, your e cost increases." - Saktoth