It's definitely not 7 lbs.! I think it's probably 8 oz. shipped (the battery in it's factory package weighs 3-4 oz.). And, incidentally, contrary to the title of the product on Amazon, it also works in the T4i (that's what I have).
By J. Conway on April 22, 2013
On a full charge, I've done events where I'm constantly switching between between photo & 1280/60fps for 5-6 hours, & I'm still at full charge. I'm using a high speed 32gb. I think you'll have to switch SD cards before you have to switch batteries.
By Chris on April 13, 2016