I wasn't about to let what could be the last day with a temperature 80's for a long time slip away. Here in Minnesota, Fall is about to begin. That means collecting data on how the battery is kept cool will soon end, ushering in the opportunity to observe battery warming.
I parked the Prius outside in the morning, set the timer for afternoon recharging, then walked to work. The weather was a mix of sun and overcast. That only kept the air temperature from getting really hot, but it still got nasty humid, which meant the A/C was a necessity for my own comfort. For battery-pack comfort, which is cooled passively by using cabin air, A/C would benefit it too... especially since it was already warm, almost 10°F warmer than I'd expect to see in the coming weeks.
The plan was to drive normally, not doing anything special whatsoever on the way home. I'd drive along the 45 & 50 mph roads to the highway using just electricity. Then upon entering the highway, I'd take advantage of the engine for merging and climbing out of the river valley. Then once on top on open 55 mph road, switch from that HV mode (mostly engine, with some battery) to EV mode (battery only). Upon reaching the 70 mph part of the highway, I'd switch to EV-Boost mode (mostly battery, with some engine).
Filming it would be interesting. I had my old smart-phone, which would capture driving data using a Bluetooth connection to an ODB-II reader attached to the Prius. That does a fairly decent job of collecting detail, though the processors on both ends combined with wireless transmission causes some zero-values in the data at times. The camera capturing video would be just a single GoPro on just a sticker-mount, aimed strategically to prevent over-exposure of the scenery without under-exposing the dashboard display. That works fairly well, though some software adjustments are still needed later to clean up lighting issues. It keeps the refresh flicker of the Eco-Meter to a minimum too.
The commute home itself was a nice example of what I typically experience. Traffic gets slowed up a bit by the highway entrance, on the bridge, and climbing the hill. But that's pretty much it. Fortunately, there's no efficiency penalty. That's what the plug is for. You get extra electricity for both propulsion & cooling.
Pay close attention to efficiency when traveling at the high speed. (Also, note how the speedometer on the Prius is calibrated properly and the raw data coming from the ODB-II reader is not. It's one of those annoying differences you cannot do anything about using an inexpensive phone-app to process the numbers on-the-fly.) Anywho, notice how even at 70 mph, the MPG gauge is held high. That's the result of the gas-engine RPM being extremely low due to the electric-motor providing most of the propulsion power at that speed. That electricity boost greatly reduces consumption of gas by favoring electricity instead. There's a button on the dashboard allowing you to select whether or not to utilize the battery power that way. Owners have coined that choice "EV-Boost" mode.
