Eldritch Battery Bug?

The Eldritch Battery keystone is (for me, at least) either bugged or not functioning as described.

The description is "Converts all Energy Shield to Mana". Upon taking it though, only a small amount was converted.

This could be a bug, or the passive is only converting my base mana? In which case the description should be updated to reflect this.

I'm particularly frustrated by this because I just spent a large amount of gold on a respec that depended entirely on this passive working as described.

It converts all your Energy Shield.

Do you have any items that provide you Energy Shield through conversion from Mana, Life or other sources? Like Ghostwrithe chest?

It converts your ES before any % Increase of ES on the tree. So essentially, the sum of your ES from gear and any other flat ES sources (like +10 in the witch/sorc starting area).

Not a bug. If you view the Eldritch Battery node in the passive skill tree and hover over the word "convert" it clearly states that the conversion only applies to your base ES. It means that it converts ALL of your base ES. That doesn't stop items from converting life to energy shield after the fact, which is what happens in this case.

So order of operations as intended is:

1. Base ES is converted to mana by Eldritch Battery
2. Ghostwrithe or Atziri's Disdain convert life to ES
3. Everlasting Gaze adds ES based on base mana
4. Percentage increases from skill nodes are then applied to both ES and mana

These are intended interactions which many people have mistakenly interpreted as a bug because they haven't read the "convert" tooltip on the Eldritch Battery node.