I have an 08' Prius with 226,000 miles on it. To the best of my knowledge the Traction Battery is original. When sitting in a parking lot, in a drive thru, or in traffic the air conditioning works well. The air is plenty cold, even on hot days. When on interstate or a 4 lane doing highway speeds it is not so cold. It almost gets uncomfortable. When I lift off the throttle or put it into B the air cools off as well. Could that be a sign of a failing Traction Battery? If the AC is based on a 300V compressor and the battery is on the low end of acceptable voltage then there could be enough voltage loss when under load to the drive motors to affect the output of the compressor and the efficiency of the system. Recently we've had a heat wave where I live, and I know high temperature and dewpoint air has an incredible amount of enthalpy so full capacity is an important thing right now. Any input is appreciated!