Instruct: Classify a given Amazon review as either positive or negative.
Query: 2 units died when left on more than 4 hours!

I had the original charger which is no longer manufactured for over 4 years. After it died, this model was substituted and I had two replacements both die the same way (being left on overnight). Now I have to use a manual timer which shuts power off after 3 hours.Weird....Ryobi was nice but said that's just the way it is...