Latino Review has some details/spoilers for CRANK: HIGH VOLTAGE.

In the first film, Chev (Jason Statham) is juiced by adrenaline. In the sequel, he needs electricity to keep his newly implanted Abiocor artificial heart beating.

The Abiocor is designed to keep you alive only for a couple of days while waiting for a transplant. It is not built for strenuous activity.

[edit]

Basically Chev has to keep his body electrically charged to keep his ticker running. Whereas in the first movie he needed adrenaline to stay alive, in Crank: High voltage he needs jolts of electricity to stay alive.


...says THIS ARTICLE at Latino Review. Much more information to be gleaned in the article, including explanations for & diagrams of the Abiocor.

I'm assuming this won't look as dopey as it sounds...although maybe I shouldn't assume that. What dependence can Chev develop in the third film? I'm thinking Twinkies might be good.