Just had a 98 degree day -- hottest yet since I bought my '07. *And* carting around four people instead of the normal one or two.
1 - to get sufficient cooling, I had to max the fan, set AC to On, and set temp to Low. (And it *barely* kept up.)
2 - the batteries wouldn't charge up. They depleted quickly to the 2-3 bar range, and then there was no forced regen. I'm assuming battery temp was too high to allow much charging. Note that the AC compressor in these conditions cycles both its electric and engine-driven stages, so it's drawing from the IMA and the ICE.
3 - significant hit in acceleration below 2,500 rpm, and it took longer for the engine to rev above that. *Bog*-slow off the line. This is the engine drag Mpress refers to, and I totally concur: 4-cylinders get their butts kicked by the AC compressor. You can literally feel and see the car lose a couple mph
if the compressor cycles in while you hold the same throttle position.
4 - when at one point it auto-stopped with only two bars SOC and the AC all the way on, I started shifting to S to prevent autostopping altogether and to *try* to get more charging. (Only partially successful on the latter.)
5 - everybody get ready to wince, but in all honestly I was doing this as a test of my car's limits in this sort of situation: with four people, AC maxed in very hot temps, no autostopping, and heavy city traffic where most bets were off for efficient driving, my mileage for the afternoon was 28.9.
Well, at least now I know.