no. build a bracket for itI have a trunk plywood floor board...would it be safe to just let it roll around underneath (assuming I wrap the terminals with rubber)?
exactlyWe're not being assholes with the sarcasm... They're all very valid suggestions.
Capacitors have no place in car audio as a voltage regulator. You are MUCH better off selling it and upgrading your stock engine wiring, as well as maybe adding a 2nd battery instead of the cap.