He is using 4 diodes across the caps so that the extra voltage passes thru after the caps are completely charged. I tried the circuit in a simulator just for fun and sure enough it works. When the current stops completely and diverts into the diodes, it drops to less than 1 amp... probably better MPG. as soon as the caps get used, the current drops to micro amps on the diodes and increases to something large in the capacitor side.