You need a peak style charger to best charge that pac. AAs are not supposed to be charged at over 1amp as a fast charge and 0.5amps for a slow charge. The real cheap chargers are trickle type and won't peak a battery. Something like this -
http://www3.towerhobbies.com/cgi-bin...?&I=LXCJE2&P=7
or -
http://www3.towerhobbies.com/cgi-bin...?&I=LXCNK7&P=7
or (bestter) -
http://www3.towerhobbies.com/cgi-bin...?&I=LXCLD5&P=7