Sanyo claims that 2000 mAh Eneloop LSD AA NiMH batteries provide about 1400 mAh at -10 °C (-15 °F).
I wonder if only Eneloops provide reasonable capacity in the cold, or if the competition does too. Do any other low self-discharge AA NiMH batteries, not made by Sanyo, also provide reasonable capacity in below-freezing environments?
I've found some tidbits which don't answer my question but are helpful.
"patrat" uses body heat and a high-drain device to keep batteries warm: "My [flashlight] is in my pocket, picking up body heat until I use it. If I use it at medium or higher, it stays warm once removed from pocket."
"Battery Guy" writes: "When it comes to low temperature performance for NiMH cells, it is safe to assume that the better the high current performance is, the better the low temperature performance will be."
Russell McMahon writes elsewhere: "I'd expect lower capacity batteries within a given size range to have somewhat improved low temperature operation, all else being equal. For example, 1500 mAh AA better than 2500 mAh AA. But the increased initial capacity may cancel this out. (Larger capacity batteries squeeze in all possible active material at the expense of electrolyte volume et cetera)."
Energizer Recharge NH15 AA 2300 mAh claim to work at temperatures as cold as 0 °C (-32 °F).
Duracell Rechargeable StayCharged DX1500 AA 2000 mAh claim to work at temperatures as cold as -10 °C (-15 °F).