I don't have a full running length as I never killed one on a single shoot. Let's put it this way, with a fresh set of batt's in my grip on my 7D, I have to change them and my batt's in my h4n before I have to worry about the monitor, so it is a good long time. Plus, they can run anything with a 12v plug so they are way more useful in a pinch then batt's you need a mount for. Also you can cut off power at the battery level with a switch so you don't risk draining them having them connected.
I was thinking about going that route and just having a ton of interchangeable batt's for everything but for me, I think this method works the best. Either way works, it's just what you prefer.



