Channel Charge( Lost Empires of Faerûn, p. 7)
You can power a charged magic item with your own magical ability.
Use Magic Device 5 ranks, ability to cast 4thlevel spells,
When you use a spell trigger magic item with charges (such as a wand or a staff), you can make a Use Magic Device check (DC 15 + the item's caster level). If you succeed, you can sacrifice a spell slot or prepared spell instead of using a charge. The spell slot or spell sacrificed must be one level higher than the level of the desired effect from the item. If the check fails, both your spell slot (or prepared spell) and 1 charge from the item are expended.