D200/300 battery mystery
My experience with those batteries (I have them in my D200, D300 and D700), is that they suddenly just don't work one day. Usually (for me) because they've been sitting unused too long. Won't take a charge, won't work in any of my cameras.
I don't use the el3's much, because my primary cameras (D300, D700) have grips with el4's in them. Those batteries never seem to run out. Periodically I pull the el3's out of the camera and charge them.