Realistic MPG Loss for AC

My mpg goes up in the summer and down in the winter so I am not concerned about fuel economy using A/C. I hardly notice the impact. I'm more concerned about using the heater on fuel economy.

I have two simple rules. At highway speeds A/C comes on at >77 degrees. At this point, the vents at full blast is unable to keep me cool. In city driving, A/C comes on at >87 degrees. At this point, all windows down is unable to keep me cool.

I think noticeable battery degradation is noticed in the triple digits like 150+ degrees when the car is parked. Low hanging fruit: Park under a tree or a garage. Sweat if you so choose in the summer to maximize fuel economy.


iPhone ?

 

The PiP, when fully charges, takes about 10% off the projected EV range when the climate control system is engaged. However, it doesn't matter whether the AC is on or off, or the speed of the fan. This is consistent with just a hardwired "subtract 10% from projected range" logic that ASSUMES the AC compressor will be running.

Has anyone ever seen a difference in EV range toggling the AC (fan only to AC-plus-fan)? This does seem odd given the extra load the AC compressor would have.

 

I think the estimate is pretty accurate.. but I usually try to get by with just one bar on the fan with the AC on.. these past fews days in So Cal its been around high 90s-100 so I splurged yesterday and went for 3 bars on the fan.

Generally speaking, my commute home gets me about 11 miles of EV (because of the net 650 ft elevation gain). I'm usually within +/- 0.5 miles of that 11, depending on traffic patterns and stop lights. With AC on, I'd say I lose another 1 mile of that.. so about 10 +/- 0.5 miles. I also always drive with ECO on.. which has some positive impact on AC electricity usage.

I'll echo what most here will say.. if you're uncomfortable with the heat, your battery probably is too.

I have some date from 9/24/2012.. no idea what the outside temp was that day, but my battery temps were 100F when I left work (which is on the higher side), Coolant temp started at 28C, or about 83F.. so outside temp was probably right around there. My car would've been parked against the side of a building that got shade in the afternoon, but sun in the morning-noon time period.

The beginning part of my trip home is 40MPH streets.. so I'd be driving 40-45.. temps rise from about 100F to about 101-103 (depending on which battery temp you're looking at, there are 3). Under moderate acceleration up to 50MPH for a short period, the battery temps rise to 102-104F. Using AC, it lowered the temps down to 100.5-103.5F. Then starts my drive up a slight incline on a 50MPH street where anything less than 55MPH will get you the middle finger. Here the temps rise significantly up to 103-106.5F before I run out of juice and the ICE kicks on, lessening the load on the battery. From there until the time I pull into my driveway, battery temps drop down to 101.25-104.75F.

 

I have been making it home from the gym every day since it got above 50 degree in all EV (trip is 11.5 round trip). Monday it was 84 degree at noon, used AC could not make it home in EV was about .5 miles from home when ICE kicked in!

 

because my commute is all ev, i don't have an hv route i can compare a/c to no a/c without actually setting one up and doing some testing. anecdotally, i don't believe i see more than 1-3 mpg loss, depending on ambient temps. i would not drive in hot weather without a/c, if you're uncomfortable, so is your battery!

 

Understood. I was trying to provide the context as to how it affects EV, so that you can draw an inference as to the effect of the all-electric AC compressor. So my thought is that when in HV mode, the small (let's assume 10% hit) on the battery from AC usage would not be likely to result in much decrease in MPG.

 

There is not "one" number that you can assign to the hit caused by the A/C. One person could be in 80F weather with the car previously parked in the shade and starts up, turns the A/C on, fan low and temp set to 78F. Another person could have parked in the sun on 100F day for hours, turns on the A/C, fan on high and temp set to low. In the first case the compressor will kick on for a minute or two, then cycle on and off, maybe on for 1/4 of the time (just a swag). In the second case the compressor is on continuously and fan is at max continuously...maybe a 5x difference in watt-hours over a 20 or 30 minute period until the EV battery is depleted.
I rarely use the A/C when commuting around just in EV (most of my miles). But I did have it on yesterday while driving in EV (A/C on ~medium, temp = 95F+) and my EV estimate went up 0.1 at the end of the day (13.3 -> 13.4)

Mike

 

and relative humidity is also a factor.

 

Anyone know if it's not recommended owning a PiP in hot climates like AZ?

 

you should post a new thread so someone with a pip in az can help you.