it's the same answer i gave you in the PM , there's no need to ask in 10 places . you can just post here.
4k lightning damage is not enough at the stage of the game where you are now . you don't deal enough damage per second , reason why you die so often . it's only ok-ish if you want to farm in easy spots (iotss/cows/k3kba) but is bad vs bosses / harder ubers ; unless you got best in slot (twinked) gear for it , it kinda sucks in mid game , so you are making it hard for yourself for no reason . the only way to increase your 4k lightning damage is with better gear (SU's) and more charms , which apparently you can't access , so why gimp yourself ?
use a spell that deals higher damage for killing bosses , such as Flamestrike or Abyss - they are better than your maxed Forked Lightning even as 1-pointers . Since you play lightning-cold , the 1-pointer Abyss should help a lot in taking more charms .