hump back or flat cells?
There are many ways to attach both a hump pack and flat pack, you just use your imagination.
As said above, zip ties can be used to secure the pack to just about anywhere the pack will fit. I have ran them both zip tied to the shock tower and on top and under the chassis with no problems as long as you secure it well.
Some aftermarket battery boxes are large enough to fit a hump pack as well. Its all comes down to user preference.
Custom straps for under chassis mount of flat pack.
Zip tied to front shock tower.
Hump pack and receiver mounted in front of shock tower on a Puller Maxx for added weight on front for traction.