You get what you pay for. If you really want one that lasted as long as the original, bite the bullet and get the Canon battery. I got a Lenmar one, and although it charges fine and fits the camera, it lasted way shorter than the original battery. Still not bad considering the price and for backup. I'm kinda wary of the really dirt cheap no-name ones as you never know how safe they pack those lithium ion cells in it.
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