Reckless Wand Wielder( Complete Arcane, p. 82)
You can increase the effectiveness of spells cast from a wand.
By expending an additional charge, you can use a wand as if its caster level was 2 higher than its normal level, changing all the spell's level-dependent effects. For example, by expending 2 charges at once, a wand of magic missile (created at caster level 3rd) can be used at caster level 5th, fi ring three missiles instead of two. You can expend only 1 extra charge at a time using this feat.