The energy boost would be almost like a caffeine or adrenaline rush; for example, if Nos were being chased and lacked the strength to scale a wall to escape, he could drain a car battery and get a boost long enough to do that. the boost would only last 10-15 seconds before burning out, leaving him weaker than before before leveling out again a bit later, and he couldn't chain together energy boosts or use them to win impossible fights or accomplish things wildly outside of his ability.