Canon Battery Pack BP-827 for the HG20 and HG21 Camcorder. Also works with VIXIA HF S10 Dual Flash Memory and the VIXIA HG20 Hard Disk Drive

Amazon shipped a generic replacement, labeled "Power2000", "ACD-763", "for Canon BP-827", with the address of a no-name company in New York. There is no official Canon logo anywhere! Instead it says "Manufacturers [sic] names are trademarks of their respective companies ... for reference purposes only ... do not constitute any form of endorsement ..."!! The barcode on the back is taped over with an external sticker that carries a different UPC code and says "Canon BP-827". It's obviously a fake. Very, very shady indeed. If I wanted a generic, I'd know where to buy it. Here, I wanted brand, and I got a knockoff represented as brand (it says "by Canon", and there is a picture with a Canon logo on the battery in the item description!), at more or less brand price. (The knockoffs are ~$50, not ~$120.) Take your pick what to think. I thought those fly-by-night outfits out of Brooklyn operated like this. Needless to say, it's going back. Simply unbelievable! Grrrr.

I have a canon Vixia HFS20.
I own an authentic Canon 827 battery and a $40 knockoff version.
The Canon battery will record for over three hours. No problem.
The knockoff version gives me about two hours. It also has the unfortinate tendency to stop charging for no apparent reason.
If you keep an eye on it, no problem. Just unplug it and start over. If you dont notice, well, your battery will be useless when you need it. You get what you pay for.
I use mine as a backup for long days.
Do yourself a favor and get the Canon. And the external charger.

Ordered the Canon BP-827 from Amazon along with the Canon Vixia HF-M31, a Canon case, charger and a ScanDisk Memory card. Received a non OEM replacement battery instead. Customer service was initially very painful and not very helpful. After essentially wasting 30 minutes on the phone and marking unsatisfied on the customer service survey, I requested a phone call. I was contacted by a very nice woman (a higher level person I believe) and now I feel like I am finally being taken care of. I hope I get the correct battery soon.

The battery that ships with most Canon Camcorders will not last very long. This is the one you want, this battery will give you 3-4 hrs of record time. Takes a couple of hours to charge.

The Battery is awesome, provides much more battery life than the stock one. It doesn't jut out as much as I thought it would. Great buy.