Windows down or A/C on?

I'm not motivated to try and teach you middle school math, so I leave this discussion with a question: what is the MPG of the AC all by itself ? How about when the AC is running full blast ?

 

Wouldn't the AC usage be half when it's at 90 mpg? I'm asking because it would seem that since the driver is counteracting the results of the AC by driving better. Otherwise, it would be the same. The draw would be the same percentage, just the variables would be different due to the driver driving differently.

 

Break your question down to components:

The AC consumption
The non-AC consumption

 

That's what I'm wondering.
I know the AC would create a draw. But why would it create a x2 draw as you suggested at 90 vs 45 mpg? Wouldn't it be the same draw?

 

Would it help get us out of the woods, to replace AC with some other "drag", say the parking brake engaged one click?

 

Would that change the resistance to be non-linear?

 

YES, same draw.
I said that as the non AC consumption decreases, the AC fraction of total energy consumed increases proportionately.

 

LOL !

 

Ah, that's where I was confused. Missed the non-AC to AC correlation. Thanks.

 

No worries.

There is something about ratios that many people have trouble with (not directed at you.)
I tried for years to explain watts and Wh to my wife. Baaad idea. Too bad joules is not a more common energy unit.

 

Ive keep the windows down in the city. AC drains the battery in stop and go traffic causing the engine to kick on prematurely. AC at hwy speeds as long as theres no stop and go

 

A bit late to the party, but here is the data I've collected for my particular commute (speeds of 30-45 mph). I used the Scanguage II to read the mpg for the trip. I put the driver's window down 1/4 to 1/2 the way, and the back right window down 1/4 of the way. This gives good airflow without sacrificing too much aerodynamics. This is on a Gen II Prius, but should be fairly similar to yours.

 

try A/C all 12 months of the year just to escape the heat and volcano smoke. the real questions are to set the a/c at 68 or 74 degrees and then on rec or not and to make it auto with vents only or auto (light off) but vent with heating ducts which is still auto but without the auto light. also the eco makes a lower fan setting.
just set it to 74 degrees with ac on. gas use should be negligible.

 

Personally I use my AC quite often and don't notice a huge difference. Some of my friends are convinced its a noticeable difference and go Windows down.

 

Haven't read through this thread, but in the Gen 3 forum it's recommended to use the AC because the high voltage traction battery is cooled from air taken from the cabin. A cool battery is a happy battery.

SCH-I535

 

I finally got off my duff, added XGauges for hybrid battery temp sensor (#2, of 3) and battery fan mode (0 through 6 I believe, indicating fan speed). On some extended hot day drives, I did partially with AC, partially without. I saw some minor temp drops when using AC, did not see it rebound when we turned it off and rolled the windows down.

I'm sceptical of AC's value, doubly so in light of it's adding a load.

 

thatz why i use it at 74 degrees because the ac compressor runs off of the hybrid battery while the ac fan is just the 12 volt lights battery. hey itz Hawaii and itz finally breaking into the 95 degrees with global warming,,, add in some volcano smoke nowadays,,, use the ac all the time

 

Yeah, guess it's a little cooler here

We were in Maui in spring time. Our place didn't have AC, but was on the windward side, on the shore, warm but the breeze made the difference. But get inland, in a parking lot, ouch.

 

Hawaii is notorious for areas of micro-climates. just today at home ½ mile from Hilo Bay it was 90 degrees, then 97 downtown then 98 at the Hilo Bay itself then back down to 88 degrees only six miles north to Pepeekeo along the Hamakua Coast. all this is in a supposed rainforest,,,