Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Read These Reviews Carefully

I have this 15 minute charger and it has appeared to have killed not only older NMH Engergizer NEW batteries but also does not charge older ones that should still have life left in them. If you read the reviews carefully you will see that the glowing reports come from people who have only charged their batteries several times and yes, that was my experience too. However, over the long haul my experience has been exactly the same as all of the others who report dead cells that will charge on other slow chargers or not at all. We all want a quick charge but that may be a technical impossibility. I will certainly never buy one of these 15 minute chargers again and I really urge new buyers to beware.