From Path of Exile Wiki
The final amount of mana is calculated with the following formula:
( Mana * %mana increases ) + ( ES * ( %ES increases + %mana increases ))
In other words:
( Mana * x% increased maximum Mana ) + ( Energy Shield * ( x% increased maximum Energy Shield + x% increased maximum Mana ))
Eldritch Battery is located on the upper right edge of the tree.
|Class||Distance from start|
- Mark_GGG (January 31, 2013 2:09 AM). "[Mechanics] Eldritch Battery". Path of Exile Forum. Retrieved August 2, 2013.