Tony Chamanadjian , Mar 21, 2010; 10:50 a.m.
Hello,
I just upgraded to 7d and now I was wondering since I probably won't use the 20d for a while should I remove the battery or can I leave it in camera?
Thanks,
TC
Bob Boudreau , Mar 21, 2010; 11:28 a.m.
It's always best to remove batteries from all powered devices when they are not going to be used for some time. Sure can't hurt!
Jim H. , Mar 21, 2010; 12:01 p.m.
You can get away with leaving it in for a month or so , but as Bob stated it is best to remove if you are not going to use the camera for any length of time, you can buy the little silicon pack of you do not have any on hand and store batteries with silicon for years , I Put the batteries in a zip lock bag myself , I have about 12 batteries or so and sometimes they might not get used for Weeks and this method keeps them safe, do not let them touch other batteries without the cover on the back of battery.They can over heat.
Tony Chamanadjian , Mar 21, 2010; 12:26 p.m.
Thank you both for a quick response, much appreciated!
Cheers!
Puppy Face , Mar 21, 2010; 12:56 p.m.
They store best half drained and in a cool, dry place.
Tony Chamanadjian , Mar 21, 2010; 08:43 p.m.
Jim Strutz - Anchorage, AK 
, Mar 21, 2010; 09:52 p.m.
Storing "half drained and in a cool dry place" is probably the best advice, but rechargeable lithium ion batteries will still deteriorate whether used or not. And used or not, you can often notice the reduced ability to hold a full charge after 2 years. They rarely make it past 4-5 years. Also, if most rechargeable lithiums ever get fully discharged they fail completely, with no recharge ability. So you might want to partially recharge every 3-4 months.
Jim Krupnik 
, Mar 24, 2010; 02:16 p.m.
I leave batteries in my xxD cameras, and only switch the bodies off when I store them without a lens in place, or when packed for travel. That way, they are always ready to go. I mark the batteries with the month and year I bought them somewhere on the battery, and once every two Months I give any of the 16 batteries that have not been used a full charge.
That has worked fine for me since the 20D first hit the market. The oldest of my current batteries are now going on 5 years, and I expect to retire those soon, but at $9 each for a Calcellular BP-511 with a cap, I think I'm getting my money's worth out of them... The BP-511's seem to outlast the lithium average life I have seen from my Point and Shoot lithium cells.
