It is possible to do it with Cosmos, however I don't know how to make it into a script. So will have to redo it each load, death etc.
I've attached my last savegame file with all three abilities from combat tree that includes power cells. Trip mines, flakcannon and omni grenade. Not sure if only the save file is needed or if the other "profile" files and such is needed as well. Included them all, the save is the manual save made 25/03/2017 @ 21:15 (9:15 PM).
You need to activate skill points cheat or my save will lose a lot of his skills and you might not be able to use it.
No, you have to freeze it. If I set above the original 3 power cells I have for one ability, it will just revert to the lower value. If I freeze it, it stays the same number. If I load a game while I have it frozen it crashes. However I can zone and teleport without the value breaking. Haven't tried switching skills back and forth.
The power cells aren't a "ammo" slot per say. The three different skills all use "power cells" but they are each independent of each other. With different speccing you can have different amount per skill. In my current build I have 4, 4 and 3. If I use a grenade and go down to 2, the others will still be 4 power cells each. So it's different for each ability.
I would also like to add that there are 2 more abilities that can use the "power cell" function. Barricade and Concussive Shot. All these power cell abilities are from the combat skill tree. Concussive Shot needs to use a certain spec that makes it use power cells. Otherwise it is on a regular cooldown.
[Edited by busybasaz, 3/25/2017 6:20:33 PM]
What Mission was you on, when you got your skills reset the next time you logged on?
Im level 120 and the Mision, EOS: Defeat the Kett, it takes a really long time to kill enemy because their HP scaled with my level