Nissan Technical Advisor 9/15/2010Try to check or better replace wires connecting from alternator, it seems that you have a bad ground wire that keeps the battery discharged.
Zeke 9/15/2010You need to check you vehicle for a parasitic voltage draw. To do this disconnect the positive battery cable, connect a multimeter set to measure current between the battery and the cable, usually if you have a current measurement of more than 25-50 milliamps then you have a parasitic draw. To find which circuit has the draw on it start pulling fuses one by one until the amperage reading is within a normal range. The fuse you pulled to get the current to drop will correspond to the circuit that has the parasitic draw on it.