After sitting a couple years without use it looks like my PC680 is dead. Besides the weight savings there is nothing to write home about with this battery as I've had a couple. I'm looking to move to a lithium battery that is the same size as the car is already set up for a 680. So, who is running them and what is your experience? From the research I've done it will cost me ~$600 for one...I suppose you get what you pay for however.