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

It's true that this is about half the price of the Canon battery. But when you consider that it's less than half the life, it's not really much of a deal. There is a great difference in battery quality among brands, as manufacturers can use less material to get a battery that holds less charge at a lower price. Some of these batteries come from disreputable Chinese sources, and they don't get even remotely near their rated storage capacity. It's an easy game to play given that most people don't have a rigorous way to test capacity. (It's also a little suspicious when the product literature and the battery case list a different capacity, but not surprising given that they are just making this all up.) I've tested off-brand batteries that were supposed to hold 900 mAh and only held 400 mAh. My guess is this battery would test similarly far off from its rated spec given how often I have to charge this.