Interaction between Ghostwrithe Tattered Robe and Eldritch Battery

If you are using Eldritch Battery and have all your Energy shield switched to Mana you are unable to further increased the converted energy shield with "increased energy shield %" nodes because your Energy shield is stated as 0/0.
If you decide to equip the Ghostwrithe Tattered Robe your Energy shield by the amount of 50% of your Health.
Should it be like that?