Opteka 2000mAh 7.4v Digital Camera Battery Equivalent to Canon BP-511 BP-512

while these batteries have extra capacity and are cheap, they're not a great value. I've had 4 of these and they all seem to start failing after a few months to about a year. I've switched back to the Canon brand even though they are lower capacity and more expensive because they just keep going year after year.

I bought two of these batteries. I charged both straight out of the box with my Canon charger. One works great while the other won't keep a charge. It costs two much to bother shipping the non-working one back so... The one that works is a five star. The one that doesn't is a no-star.

I purchased 3 of these Opteka batteries for my Canon 5d MKII. I purchased them about 2 weeks ago. 2 of the 3 batteries I purchased basically died in that they won't charge anymore so their useless - I trashed them. The 3rd battery lasted until a couple of days ago and now it to won't charge. I went to best buy and purchased 2 Canon batteries that work perfectly. I should have done that in the first place. Don't waste your time and money, just get the Canon branded batteries so you can concentrate on your photos not your batteries.

I purchased two of these as backup batteries for my 50D. Both seem to hold a charge and work exactly like the official Canon battery. Plus, they are much cheaper. I'm very pleased.Follow-up one year later: Both batteries are still going strong -- I know that some cheap batteries conk out after a short amount of use, but these don't seem to have that problem.

At $9.98 the Opteka 2000mAh battery is not only cheaper than the stock Canon battery, but it holds more power for longer use (more photographs) between charges. The quality must be there too because the manufacturer guarantees them for three years. I purchased four about three months ago and have had no problems with any of them.

Works pretty well with my 20D. Seems to have a little shorter battery life than a 2000mAh battery should have.

I have stopped buying name brand batteries. They are batteries that work great and I can afford to buy 2-4 for the cost of one brand name battery. Excellent battery life and I have never had an issue with the batteries. Buy them and you'll be happy.

These have worked suprisingly well for my wife's camera. They hold a charge just as well as the Canon batteries at a cheaper cost. I can't say much more on them, but my wife, a professional photographer, has no complaints what-so-ever.