Instruct: Classify Amazon reviews into positive or negative sentiment
Query: low battery life

my mom had a B&D; cs100(3 or 4 years old)i replaced it with a B&D; ns118,the salesperson told me the battery life was not very good but i boughtit because of the light weight--after about six months i am replacing itwith a B&D; cs100(if it didnt have a back up battery it would have beengone a long time ago----just doesnt have the power the cs100 hasi have a B&D; cs100 that is several years old and it works very good--gottired of cussing at the cord