Impressive battery life retention on Wiz and NDSi. I haven't played my Wiz for 2 weeks now and the battery life indicator is still full. For the NDSi, it's been 6 months since I last played it and battery is also still full. Is this behavior universal among lithium polymer batteries? I'm so used to battery life dying even without usage but that was nickel polymer battery era. Maybe I should upgrade my AA nickel rechargeable batteries to lithium polymer if there is such a thing.