If T-800s sent back in time were made to be very hard to destroy, why
were they built to have battery that would be susceptible to rupture, instead of diverting that energy to another battery for which it had or closing it off to further damage the T-800?
In other words, we see that the T-800 is this movie was built with two batteries, one of which ruptured. But what would have made it susceptible to being destroyed was not having a sharp cutting tool. Had John not had a sharp cutting tool, it would have blown up right then and there. Since the T-800 was their defense against the T-X, it would have allowed the T-X to easily find them and kill both of them.
THERE IS NOTHING TO FEAR. COLLEGE FOOTBALL IS HERE!!!