Best practices for storing a replacement battery? My early 2011 MBP has been giving me the "Replace Soon" battery warning, and an app I have says that the battery can hold 57% of its original capacity. I bought a new one on Amazon, but now I've decided to wait as long as possible until doing the surgery, in order to squeeze as much life as possible out of the current battery before beginning the new one's life cycle.

My question: What do I do with the replacement? It's currently in the cardboard box that it came in (not the big box from Amazon, a smaller box inside that). How can I store it for a month or so while keeping it happy and healthy until the time comes to give it the privilege of powering my computer?
The recommended storage temperature for most batteries is 15°C (59°F); the extreme allowable temperature is –40°C to 50°C (–40°C to 122°F) for most chemistries. While lead acid must always be kept at full-charge during storage, nickel- and lithium-based chemistries should be stored at around a 40 percent state-of-charge (SoC). This minimizes age-related capacity loss while keeping the battery operational and allowing for some self-discharge.