Re: NVG BATTERIES - ever had a problem?
I have used them while with RAF - no issues, but I was careful. USAF horror stories like many above mean we've switched entirely to AA.
Li - go bang seemingly random (overheat, wet, shorted, no apparent reason, etc), are hazardous when disposed of (must utilise special handling procedures), die off nearly instantly, expensive, hard to get if not in mil supply channels
AA - not nearly as hazardous (no licenses/permits/documentation), don't normally go bang under any circumstance (have seen 'em do it though), easily obtained, cheap, die off rather slowly with reasonable warning to operator.
My vote - AA