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I've got kids so driving around with the AC on is a must.

This leads me to the question of "What does running the AC hurt in terms of FE". I know that:

1) It steals power from the engine when the engine is on, so lower FE when your ICE is on.

2) I assume that it draws KWh from the pack when the ICE is off.

3) I assume that it sometimes effects the decision of the ECU to cut the ICE.

4) I assume attempts to go stealth mode (non EV mod) with AC on, usually trigger the ICE to fire up.

Does anyone know if these three points are correct, or not?

If they are, here's what I've started doing. I set my AC to auto, recycle, 75F. There are thumb controls on the '07 for AC/Auto on/of and recycle on/off. When I near the end of my pluse (and I want the ICE to cut), I flip the AC off. Then once the ICE has cut and I'm in my glide, I turn it back on, and toggle recycle. If during my glide I need to extend it with EV assist, I toggle the AC back off until I'm done with EV and ready to start regen deceleration.

As a side note, I always use recycle since the primary cause of heat fatigue in Houston is humidity not heat itself. With the AC running the cabin is usually lower humidity than ambient. I've also stepped it down from 75 to 72 if it's really sunny.

Anybody have any views on using AC efficiently while trying P&G?

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Hi Dan:

1) In all vehicles but the Prius II (and HCH-II while not on MAX). IIRC, the AH has an electric A/C Compressor stage as well as the mechanical. I will have to look that one up?
2) In the Prius II, indeed.
3) Yep but IIRC, it only depended on the SoC, not an ECU decision to rev up the ice for more power to the pack or anything like that.
4) At low SoC, yes but you can EV (forget all the talk about what is EV and what is stealth as it is a moot point) with A/C running.

___During the Prius Marathon Attempt, I gave a clinic to a couple who had just come home from a camping trip. The Prius-II loaded with camping gear, it had < 5K miles IIRC, tires at dealer pressures (whatever that was?), 3 occupants including myself and it was 86 degrees F. The A/C was set at 75 degrees F. The 20-mile RT average on the course filled with lights and traffic that afternoon was 86.x mpg. It was impressive as all get out in my book given we were not “sweating it” ;) but simply driving a std. P&G using the terrain and Rabbits as I always do :) Nothing can touch a Prius II in that kind of traffic and in those temps while still being comfortable riding A/C as needed!

___Good Luck

___Wayne R. Gerdes

This makes me feel much better about hot weather, as driving the Accord with the A/C on felt like throwing gas out the window. In order to salvage anything in that car I had to run the A/C at low loads only, which was a pain. Even then the FE loss was in the 15% range. And it didn't help that the car was black on black with leather. :eek:

There's about a 50/50 shot that I'm going to be transplanted to a Houston-like climate (Columbia, SC) as soon as two months from now, just in time for the insanely hot and humid weather to start. From what I've heard, the Prius will do better with the A/C on because it allows the batteries to stay cool and efficient. They supposedly shut down to minimal load/charge rates above 120F or so, kinda like they do below 32F. Even coaxing 50mpg out of her in that cold soak situation can be a nightmare. I'm thinking a relatively dark tint job would be money well spent in the name of both battery and driver health.

There's about a 50/50 shot that I'm going to be transplanted to a Houston-like climate (Columbia, SC) ....
Hey Tim, stop off in central VA on your way if you can and say "Hi."

If/when you get to SC, you might still avoid the AC on short trips with a "cold" ICE. I made the mistake once during the peak of last summer's heat of turning it on while making a couple of stops (without shutting down) near my office after work. I said, "Heck with FE, I'm gonna cool off." That was the last time. My first five minute segment was lower than most I've seen in the winter. The AC just kept sucking juice out of the battery, and I didn't think the ICE would ever cut off.