I purchased two DVXuser.com batteries and a Turbo charger. Big batteries but, one of them failed during a very important shoot (all shoots are very important) in LA. The bad battery developed a swollen spot near the contacts after less than six charging cycles! The remaining battery saved the day.
I emailed DVXuser.com twice, including photos of defect but NEVER got a response. If one fails, you are on your own, DVXuser was no use to me.