why I have to reset My Mac pro battery every few days

I have the new Mac pro I7 processor almost 1 year old. The day the grantee expire on ward:

Every few days, or whenever I connect a charger or some time connecting my I-phone, my Mac Pro die on me, the Mac cannot be charged nor it can start; the power button is not working nor any combination of keys; until battery reset is done (battery cable disconnect for 1 sec and reconnect again) then every thing back to normal; I changed the charger 3 times still happening.

Can any one tell me what should I do?