How important is it to completely discharge my camera battery and how often should I do it?

Question

I am not really up-to-date regarding how today's batteries should be discharged/charged to keep their life at a maximum possible level.

I have a canon 60D camera with the LP-E6 battery, but I believe this applies to any camera/battery which isn't old and thus uses a different technology.

If I have 2 batteries available, is it a good idea to always discharge one of them completely (until the camera refuses to work anymore), and then swap it with the other while charging the empty one completely? Or is this process useless?

Someone should clear this up once and for all.

EDIT: Since there are requests to provide more info about the Canon 60D battery, here it goes:

Official Canon battery called LP-E6, DC 7.2V, 1800 mAh (Li-ion), 13Wh

Now correct me if I'm wrong, but a Li-ion cell has a nominal voltage of 3.6V, therefore to have a total voltage of 7.2V, the battery must have at least 2 cells. I said at least, because there may be another pair of total of 4 or even 8 cells in a parallel connection, resulting in higher capacity. Either way, unless I'm wrong, the Canon LP-E6 battery is multi-celled.

Answer

If the batteries are multi-celled, then yes, full discharge is good, once every couple of months. There are sensors that combine readings from multiple cells to determine capacity and balance the cells to improve efficiency and overal capacity. Other than that, Li-Ion still prefers shallow discharges.

To maximize Li-Ion batteries' life, store them in cold environment such as a refrigerator. Be sure to cover the contacts and/or wrap in bags to eliminate condensation. This also applies to letting them reach room temperature before putting them into the camera (or you risk condensation again).

I only did these kinds of things with my laptop battery whose compartment illogically placed next to the hot hard drive. Heat kills batteries.

The 60D battery does indeed look multi-celled. Still, for cameras, I'd just buy cheap 3rd-party batteries and not worry about it, personally.

Good resources:
Battery University
Candle Power Forums

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