Power failure

These are just some of the batteries that I've have used in my camera since starting this blippin' lark in August. It's become an obsession, and I've trained myself to always take the camera with me no matter WHERE I go, and to always have a spare set of batteries. My concerns re recycling and ongoing cost have led me to nvest in a set of rechargeable batteries and a charger. Having put the first set in my camera, it immediately began to warn me that battery charge was low and I understand from my sister who is much more au fait with this than me that rechargeable batteries become increasingly unreliable and prone to quick discharge. Does anyone have any ideas, hints or tips, or should I just resign myself to increasingly high costs and a guilty conscience? Your feedback would be appreciated.
PS I know it's not a very interesting blip photo!