Bern101 wrote:And what about putting a 2012 battery with the cold weather package in a 2011 Leaf which does not have the cold weather package?
I think that while it would be possible to use the battery, you can't use the Cold Weather package as the power for the heaters comes from outside. Look at the front of the battery: if it has a BIG 2-pin orange connector and a smaller to the left and the round control connector to the right, then the smaller is for the Cold Weather (heater) power. On cars without the Cold Weather package, the smaller connector is absent.
The car has a relay (contactor) to provide power to the Cold Weather package, plus the cable to the battery with the smaller orange/red connector. If your car does not have the Cold Weather package, that is absent so the battery cannot use its heaters.
Hope this clarifies,
Thinking about this a little more - I think that it might be possible to put the non-Cold Weather package front plate on a battery with heaters (or move the heaters into a battery that did not have them) and wire a small contactor from the battery pack (similar as the pre-charge contactor)
to be closed only when the main contactor is closed *and* temperture is below a certain threshold. So, wire a thermostat contact in the 12V line that taps the coil of the main contactor, to power the extra "heater"contactor.
It can work, but it definitely is not standard and the risk that you drain your battery and brick your Leaf is your own choice.
So, use this idea just for that - to give you an idea.