?”? ??”? ?’ ??”?:
The Shulchan Aruch says you may give as much as you want, the Rem”a says not to give more than a fifth for one may need that money for himself for “briyus”.
(I found this in the sefer: ????? ???? ?’ ?, ?’ ?”?; ?”? ?”? if you want more info, you can look it up there)