The only battery interchangeable with the 630wh is the BT-E8035-L which is a 504wh in the same longer size 630 case. I believe most all bikes spec'd with the ep8 and 504wh batteries use a shorter cased BT-E8035. (No "L" as-in "long").
If your Heckler has the BT-E8035 then no, the 630 won't fit. Hopes this helps.