How long will battery stay charged?

Let's say you charge lp-6 battery to 100%, pit it in the camera and turn it off. What happens to that battery over the course of weeks, months? How long would it hold a charge or be expected to hold a charge?

Every Canon manual I've ever read says to store (long-term) the camera with the battery removed. They also say to re-charge and test camera before an important shoot.

Li-Ion batteries are best stored at something below a full charge (80%?), but I'm not sure where I got that bit of info. It may be fiction, too.

I don't think any of my SLRs have ever sat unused for more than a week. I don't charge until the battery gets below 20%. I've never had a 20% battery die on me unexpectedly.

Charge retention? Better than an eneloop cell but not as good as an alkaline cell. For long term storage, the charge should be ~40%. More charge places undo stress on the battery. Less charge increases the chance of the battery's voltage, over time, dropping below a safe level.

As for leaving the battery in the camera, I've gone weeks without a noticeable loss of charge.

I keep all my batteries charged and recharge after a shoot
It is better for me and i guess less for the batteries
But i can always grab my bag and shoot
If a battery was not used for a month it will drop to 90%

On the latest bodies, there is a capacitive battery holding the camera settings, and it charges from the main battery. I would believe you want to store the batteries in the camera.

Frodge, I also see you have a related companion thread so my reply attempts to help on both.

There are a great deal of variables (under user control) on batteries. Hence it is almost impossible to predict battery behavior. For a good discussion on things go to https://photography-on-the.net …/showthread.php​?t=1021598.

An even better discussion (by Canon) is at http://www.learn.usa.c​anon.com …_e6_battery_art​icle.shtml.

With my 60D, acquired about the time you acquired your 60D, I also get two bars on my battery. If I put that battery in the camera in a fully charged state, after about three months it was at about 60%. At least that was the case last winter, when I chose to spend winter on the warmer west coast as opposed to Philadelphia.

Thanks for the help!