We're up in the mountains and noticed a couple of things with our '05 Prius. 1. Rear vent activating often despite not using the AC in 90 degree weather and some elevation climbing....Should we be concerned and is there anything we should be doing to help? 2. Climbing for over an hour, roughly 2-3k ft has taxed the battery to where we're basically at 1 or 2 battery bars ...should we be concerned and what can we do to improve it?
You would have been better off using the AC. The battery likes it cool. I don't think you have any problems, just keep the traction battery a little cooler.
As above. Don't worry about the traction battery. The HSD will take care of it. Do keep the interior at a comfortable temperature, as that is what cools the traction battery. Keeping the windows closed and the A/C in "auto" will save fuel (the car is actually more aerodynamic enough to save more fuel than having cooling on wastes). It will also help save your hearing having the windows closed. In the mountains it's normal to see the battery level go down quite low and also to see it go full green on the downhill side. There isn't a lot of power stored in the traction battery so you will see big shifts in the level.
