[QUOTE=nitramjr] Any experts out there know what kind of horsepower it takes to run a car a/c? QUOTE]

Around eight horsepower.

 

I think it comes down to a matter of efficiency. The energy to run the AC is essentially all coming from the ICE, so the question is whether it is significantly more efficient to run the engine to power the AC or to convert the energy to the battery and then back to an electric AC. The engine doesn't seem to be particularly efficient at charging the battery on its own so I'm wondering if it doesn't make more sense to run the ac directly off the ICE?

Also, running the AC on battery would further drain a battery that doesn't seem to have much capacity to begin with. For stop and go driving I just don't see the vehicle being able to effectively maintain a charge that can both assist in acceleration and run the AC at the same time. I know if I had electric AC in my MMH the ICE would be running alot at idle to recharge the battery anyway.

 

TimK and Teester: Don't forget about the regenerative braking. Sometimes it sounds like you guys are saying the only way the High Voltage battery gets charged is from the ICE. I would like to think that the regen braking does more of the charging.

 

I live in San Antonio, Texas. It's hot here every summer and doesn't let up until, oh, maybe Halloween. We get an occasional cloudy day but it remains humid, otherwise the sun's beating down oppressively.

And yet I don't feel my hybrid is "failing me when I need it most." I run the fuel economy-friendly A/C setting anytime I'm in the vehicle, unless the vehicle's been parked for a long period outside, in the sun. In those instances, the vehicle has generally been parked a good while, and the ICE has to run anyway for a bit, so I kick her into Max. A/C to cooldown quick, then switch back to fuel economy friendly mode for the rest of my trip.

I avoid using Max. A/C but I don't view it as a hybrid-killer. Use it if you need or want, just know it has an affect... like anything else in any vehicle. I keep my fan set on 1 (lowest setting) and find the A/C in fuel economy mode even at not-full coldness setting (all the way left in the blue section of the climate control ****) still chills me to the point I fiddle with vents.

For long EV periods at peak daytime heating, with people in the back seat, yes I will click in to Max. A/C as needed... use it when you need it. It's like having to aggressively accelerate occasionally due to either traffic or to avoid a potential issue -- it's not fuel efficient but use it when you need it.

Just my 2 cents. I'm VERY temperature sensitive, having a very narrow range of temperatures where I feel actually "comfortable" -- neither too hot nor too cold. I can tolerate my FEH just fine, and as mentioned earlier, have it overcool me almost as often as to cancel out the EV segments where I'm parked awhile and have to ponder, "Max. A/C or wait til the heat level builds a bit and open the windows 'til I'm underway again?"

Your mileage of course may vary.

I will note that my FEH is my first vehiclle that I am definitely getting the front windows tinted on. Check the legality of doing so in your state, and to what light transmittance level (eg. the factory tint on the FEH is reportedly something like 20% or 24% light transmittance, which means 20-24% of light rays are transmitted into/out of the tinted glass; for comparison, "limo tint"/black is 5% light transmittance.) That should help with keeping the oppressive sun from heating up the cabin as quickly as it otherwise will, and avoid one's body feeling hot due to sunlight streaming in on one's legs/arms when the cabin air temperature is actually not fluctuating.

 

Well, if you trace it back, the energy recovered by regenerative braking is coming from the inertia of the moving vehicle.... the vehicle is moving due to the ICE.

There is no other source of energy input other than the ICE.

 

Exactly... You don't even get all of the energy back due to friction losses.

 

I'm with 'GeekGal.' I'm not in a very hot area, but our daily temp has been over 90 for most of the last three weeks. Even on high EV trips, if I have the A/C on internal recirculating, I'm fine. It takes about 5-10minutes for the engine to kick off when I start the car. During this time I'm getting max cooling anyway. Then, I keep as much of the cool air in the car as possible by shutting off the outside vents. The way I figure, if you've already cooled the air, might as well still use it.
Actually, I think the air conditioner in the Escape is more powerful than that in my Explorer, or at minimum the vents are set to hit you more. I find that I have to dial down my A/C on trips because I get too cold.

(I'll admit one caveat-- I'm comfortable at 80 deg if I'm sitting still. I expect the winter gas mileage will be less than this summer.)

 

Teester and Randy covered my thoughts on the ICE....as for the AC, with my 7mo old son in the back seat I can get away with no AC in the mornings, but on the way home at 4:30pm and 90+ temps it is Max AC the whole way home. This ends up giving me a FE of about 24MPG for city driving on Max AC.

 

This really helps a LOT. It is not legal where I live but I have done it for years anyway & never had a problem. I tinted the front windows at 20% on my 05 FEH & added a windshield band. I also added in-channel vent shades.


These changes made a DRASTIC difference in comfort in 90+degree hot sun conditions.

~John

 

http://www.iwfa.com/iwfa/Law_Chart/L...art%204-06.pdf

Here is a chart of state tinting laws. I can't vouch for its current accuracy.