I included the help section post I made just for reference. Effectively, the Arc Battery Mod does not have any effect unless the Class Ability does its secondary effect. For a Hunter, this is a dodge that either restores ammo to the currently equipped weapon's magazine, or resets the cooldown on the melee. It says "... during activation" but it really means "if the secondary effect of the ability is triggered" so there is no bonus from the mod for activation of the Class Ability unless your mag is less than full or there is an enemy nearby to activate melee cooldown reset. This is a bad, and probably unintended implementation of the described effect. My suggestion would be to increase the overshield duration that is granted by the mod just slightly as it only has effect during the dodge itself, and to allow the mod to work without the secondary effect being triggered. As this takes up 5 of the Energy Capacity on armor it's expected to do a lot more but unfortunately falls short of delivering effective results. I grinded for this for quite a while, as its among the final tier of Seasonal Artifact unlocks and I'm very disappointed with it. :(