I was looking to get into some cheap but reliable NiMH batteries for temperature resistance, leak resistance, and longevity (in terms of self-discharge) to put in the lights in our car and home emergency kits. I picked up the Duracell Ion Core 1000 charger + 4xAA package, plus a pack of 4xAAA to try them out. The charger + 4xAA was only $13, but after reading the reviews on here I thought they'd be well worth it. I charged the AA together first, then the AAA together. All four AA charged up and seem fine. But one pair of the AAA just wouldn't finish charging, even a few hours after the other pair was done. I unplugged the charger and pulled out the pair that was charged up, and when I plugged the charger back in, the remaining batteries triggered the flashing red "battery problem" indicator pattern on the charger. This is disappointing... since I don't use these lights a lot, and what I really care about is being ready when I need them, I think I'm going to end up sticking with Energizer L91/L92 primaries instead of worrying about charging. I'd love to invest in a decent setup like a Maha C9000 with some Eneloops and Imedions, but it's hard to spend all that money up front. I'm sure Duracell is targeting consumers who don't want to spend a lot, but if the batteries are "bad" out of the box... I guess it's just more evidence that you get what you pay for. :-(