Real World AC Effect on Battery Range

I am interested on this too, As there is not way to figure from the 'dash board display' how much Electric power is consumed for A/C, Toyota should add this in their next software update .

 

I've noticed when the Auto A/C that if the fan speed is maxed out, you can actually watch the EV miles drop while stopped at a light. I can eke out a little more range by manually adjusting the set temperature up so that the fan speed is 3 bars or less. I find this gives me adequate cooling for all but the hottest of days, where I'll go up to 4 bars. You can definitely gain something a noticeable amount of EV miles doing this at the expense of slower cooling. I find that the extra fan speed doesn't cool that much for the extra energy cost.

Also, my car is tinted, so this may work less effectively on untinted cars.

 

Here's a little information about Lithium Ion Bats, although the article is using smaller bats as an example. I do think temp has a large effect on the life of our bats.

How to Prolong Lithium-based Batteries - Battery University

 

Using Torque (an Android app connected via OBD2 Bluetooth adapter), you can see the current go up as fan speed increases. I dont know how accurate that reading via OBD2 is though.. but it is measurable. I have a log somewhere that I recorded as I drove home with AC/Fan on. I did play with the fan speed during my drive home, but I cant recall what I did at the time and I didnt take any notes. I have a post here somewhere, I'll link it if I find it.

Here it is:

Maximum EV range | Page 2 | PriusChat

Improved search feature works great.

 

is there any way to know the voltage that the A/C and fan use? So we can calculate wattage. Then enter the data here: PC won't let me post the link, so here it is here:
A friend just sent me this link. You can put it your start and stop address and it will calculate your expected EV consumption.

www.jurassictest.ch/GR/

I just tried my daily route from the previous post and it was spot on.

PS, the Volt is known as an Opel Ampera in Europe.

Read more: http://priuschat.com/threads/poll-do-you-use-google-maps-to-get-max-ev-range.113249/page-3#ixzz26Ii58sEj

 

What would be a killer display would be a pie chart showing where battery power was being allocated, both instant and well as for each trip. If your trip allocation showed that 30% of your kwh was sent to the Air Conditioner, 60% was sent to the drive train, and 10% was sent to the Headlights, what would you do? drive without the headlights on?

 

putting 2.7kwh for the battery in the LEAF specs is very close to what my PIP EV is getting

 

I measure 1500w-1900w current draw when the A/C is first turned on and temps are 95F+ outside. The system (in auto) will ramp down slowly over the next 20miles and current draw will drop to about 600w-800w. In cooler temps and a higher temp setting of 78F or more, the current draw drops to 300w and may turn off completely for a bit.

The point is, the hotter it is outside the larger the current draw and the more battery power you lose to cooling air.

 

Here's what I got when I entered 1500 watts into the equation I also put the PIP's curb weight into thequation

 

this is my typical drive to work going 25mph

 

It will certainly matter. The Prius uses a variable compressor, so generally the larger the delta between the cabin temp and the auto target temp the more power the compressor will draw. In the past it was noted that in auto mode the compressor power scales down as the fan speed drops. To the second order the larger the delta between the outside temp and cabin temp, or the more direct sun coming in the harder it will run to maintain the target temp due to the heat load.

I can't seem to find a curve of amps or kWs as a function of compressor speed or delta temperature. Seems like that could be plotted with a scangauge if anyone has one, and should probably be similar across all gen 3 Prii.

I had seen mention that the Gen 2 compressor had a max power of 3.4kW. That seems to jive with our experience with the Gen 2 in AZ, if you sit and precool the car it can deplete the stock battery (probably ~3-400Wh) in about 5 min causing the ICE to start. So you can get a sense that when its blowing at full power (ie when trying to bring the cabin temp down) the power consumption can be significant.

As a purely hypothetical example, lets say you were cruising at 40mph in EV. Lets say normally you'd expect 3000Wh / 200Wh/mi = 15 mi range. At 40mph the compressor at max power would be using 3400W / 40mph = 85 Wh/mi. So the expected range would fall to 3000Wh / 285 Wh/mi = 10.5 mi. Those are all fairly made up values, but its in the ballpark. This represents the worst case bound at that speed. At a lower speed the range impact would be worse, and at a higher speed not as bad. Now if you can adjust your settings to get the compressor to run at lower speed, that will vary the impact between the full 15 mi range at no AC use and the 10.5 mi range for full power.

Rob

 

my commute is 15 miles at avg. speed of 27mph. without a/c, i get home with around 2.5 miles of range left. if i set auto a/c to 79 in eco mode with outside temp around 90 and high humidity, i get home with arounf 1 mile ev range left.

 

When you guys use "EV range" as a sort of battery meter, is there a hard coorelation between SOC and EV Range? I ask because the Volt is not. On the Volt, the EV range is estimated on some past driving heuristics so for the same SOC if I have been driving downhill I will have a higher EV range displayed than if I have been driving uphill for the last 5 miles.

 

same as volt. it's the state of charge combined withpast driving habits. it's pretty accurate if your habits don't change!