many years ago went to a sound competition for deepest bass sound,i can remember a vw polo i think had 6 x 063 batteries in boot=high performance ones and 30 mins charging at 2000 rpm before test,test was think 20 seconds long and 6-8 people to hold windows in place all had big beefy ear protectors.
after the 20 sec deep bass test all 6 batteries were flat,now thats serious power