Extreme Heat's Effect on Range

[Buffalo Bob]

Sorry for the novel... I'm planning to depart on a trip from AZ to WA this weekend. Following both this forum's and one of ABRP's recommendations, my current plan is to travel from Phoenix to Flagstaff, charge up, and then travel about 270 miles to St George, Utah to charge again. The problem is that there seems to be no truly reliable chargers en route. (There is a ChargePoint location at around 210 miles in Kanab, Utah with a PlugShare score of 10, but all of the chargers were noted as broken on 6/3/24.) If I charge my Pure AWD to 95% in Flagstaff, I would have to average at least 3.1 miles/kWh to make it to St. George. Given that this is a cooler (higher elevation) route with a net elevation decrease and lower non-freeway speed limits, achieving 3.1 miles/kWh seems very doable, and well below my 3.7 average, but that possible lack of alternative charging concerns me.

The are alternative routes through LA and Las Vegas with more charging options, but they involve a lot more desert travel on a weekend when record-breaking heat dome temperatures are expected, and the more remote chargers in places like Quartzsite don't have the greatest reputation.

My biggest question is what people have experienced range-wise when driving in something like 110 degree heat, and the car is working hard to cool both the batteries and the interior, as even these alternate desert routes do have fairly long intervals between chargers.

Perhaps I'm overthinking this, but the heat-related part of the equation is new to me. Any advice would be greatly appreciated.

 

[xponents]

Sorry for the novel... I'm planning to depart on a trip from AZ to WA this weekend. Following both this forum's and one of ABRP's recommendations, my current plan is to travel from Phoenix to Flagstaff, charge up, and then travel about 270 miles to St George, Utah to charge again. The problem is that there seems to be no truly reliable chargers en route. (There is a ChargePoint location at around 210 miles in Kanab, Utah with a PlugShare score of 10, but all of the chargers were noted as broken on 6/3/24.) If I charge my Pure AWD to 95% in Flagstaff, I would have to average at least 3.1 miles/kWh to make it to St. George. Given that this is a cooler (higher elevation) route with a net elevation decrease and lower non-freeway speed limits, achieving 3.1 miles/kWh seems very doable, and well below my 3.7 average, but that possible lack of alternative charging concerns me.

The are alternative routes through LA and Las Vegas with more charging options, but they involve a lot more desert travel on a weekend when record-breaking heat dome temperatures are expected, and the more remote chargers in places like Quartzsite don't have the greatest reputation.

My biggest question is what people have experienced range-wise when driving in something like 110 degree heat, and the car is working hard to cool both the batteries and the interior, as even these alternate desert routes do have fairly long intervals between chargers.

Perhaps I'm overthinking this, but the heat-related part of the equation is new to me. Any advice would be greatly appreciated.

There has been research pertaining to this that show EVs losing 20-30 percent of their range when the temperature is above 95 degrees, this can be seen by googling “extreme heat evs.” Therefore, I would prepare for an ABSOLUTE worst case scenario of about 240 miles of range (using extrapolation with your 3.7 average). This would lead to 2.6 mi/kwh, which is lower than what you would need.

This rule may not apply to the Air, though. I have not come upon a “rule” for the Airs, but the 20-30 percent range loss seems to be a common guide for EVs.

 

[BS8899]

Sorry for the novel... I'm planning to depart on a trip from AZ to WA this weekend. Following both this forum's and one of ABRP's recommendations, my current plan is to travel from Phoenix to Flagstaff, charge up, and then travel about 270 miles to St George, Utah to charge again. The problem is that there seems to be no truly reliable chargers en route. (There is a ChargePoint location at around 210 miles in Kanab, Utah with a PlugShare score of 10, but all of the chargers were noted as broken on 6/3/24.) If I charge my Pure AWD to 95% in Flagstaff, I would have to average at least 3.1 miles/kWh to make it to St. George. Given that this is a cooler (higher elevation) route with a net elevation decrease and lower non-freeway speed limits, achieving 3.1 miles/kWh seems very doable, and well below my 3.7 average, but that possible lack of alternative charging concerns me.

The are alternative routes through LA and Las Vegas with more charging options, but they involve a lot more desert travel on a weekend when record-breaking heat dome temperatures are expected, and the more remote chargers in places like Quartzsite don't have the greatest reputation.

My biggest question is what people have experienced range-wise when driving in something like 110 degree heat, and the car is working hard to cool both the batteries and the interior, as even these alternate desert routes do have fairly long intervals between chargers.

Perhaps I'm overthinking this, but the heat-related part of the equation is new to me. Any advice would be greatly appreciated.

I drove my AGT this past Saturday (Jun 1) from Phoenix to Marin County. I don't recall the temperatures, but they are probably in the 90s-100s. I set the speed @75mph. I was getting about 3.6-3.7 miles/kWh. If you drove at 80-85mph, it will be substantially lower. I found speed is the major modulator.

 

[BS8899]

I drove my AGT this past Saturday (Jun 1) from Phoenix to Marin County. I don't recall the temperatures, but they are probably in the 90s-100s. I set the speed @75mph. I was getting about 3.6-3.7 miles/kWh. If you drove at 80-85mph, it will be substantially lower. I found speed is the major modulator.

I travelled on I-10/I-215/I5. Therea re plenty of charging options en route.

 

[Adnillien]

When I have driven in 118 degree heat I notice about a 10% loss in efficiency compared to the same drive at 95 degrees.

 

[Buffalo Bob]

When I have driven in 118 degree heat I notice about a 10% loss in efficiency compared to the same drive at 95 degrees.

Thanks. Is 95 about normal?

 

[Steveinarizona]

Thanks. Is 95 about normal?

In the winter.

 

[TLamm7751]

I drove about 75 miles yesterday with exterior temperature of about 90 degrees. The car had been sitting outside, so it needed a lot of A/C. For that 75 miles, driving about 75mph average, the efficiency was around 2.5-2.6kw. I noticed it starting to improve a bit toward the end of the drive when the A/C had finally stabilized, etc. If I went 100 miles instead, probably would have seen an overall overage of 2.8 or so. But, then again, 90 isn't really that hot. If I were personally "budgeting" my stops, I would probably use 2.5kw to be conservative.

 

[Steveinarizona]

I drove about 75 miles yesterday with exterior temperature of about 90 degrees. The car had been sitting outside, so it needed a lot of A/C. For that 75 miles, driving about 75mph average, the efficiency was around 2.5-2.6kw. I noticed it starting to improve a bit toward the end of the drive when the A/C had finally stabilized, etc. If I went 100 miles instead, probably would have seen an overall overage of 2.8 or so. But, then again, 90 isn't really that hot. If I were personally "budgeting" my stops, I would probably use 2.5kw to be conservative.

Elevation changes can also make a big difference.

Yesterday in my Genesis I was driving home very fast, passing others on the highway and city streets, with the temperature at 101 and going from about 1180 ft above sea level to 1440 feet above sea level for 24 miles. AC on full after car had been sitting in the sun for four hours. My lifetime average is 3.0 and I averaged on this trip about 2.4. If I had been going in the other direction I would likely have averaged around 3.0 driving the same route and style (except for direction). So, all other things being equal, elevation changes make a great difference as well.

 

[joecrna]

Sorry to revive such an old thread. Just did Orange County to Phoenix 3 weeks ago. Car was loaded with luggage and temps in OC were in the 70s. By Riverside it was 90 and traffic was horrible. By the Curacao Summit it was 100. By Quartzite, 104 the rest of the way. With all of the charging it took 12 hours. I was getting 2,5m/kwh. Half of the chargers were down and the rest always had 6 or more cars waiting. This made for some stressful miles. The return was worse but less waiting for chargers. I run 78 mph and usually get 3.3m/kwh. These are supposed to be cars and must function as such, climate system, lights and radio all on. My only concession is speed and that pisses me off. The general public will not tolerate this from cars. Temp on way haome was 108-105 whole way until West of Riverside. I got a whopping 2.2m/kwh. There are barely enough chargers across the dessert to do this with the non functional chargers.

 

[skndrni]

I didn’t travel as far today and went 122 miles roundtrip, Pasadena to Malibu to Diamond Bar and home to Pasadena. Temps were between 90 and 105 the entire time topping out at 80 mph in some stretches, some Malibu stop and go traffic, some steady freeway. Cost me 40%. So that’s 3.465 mi/kwh. Obvi YMMV. Literally.

 

[Rogue]

Just some inputs. Have you considered the shades Lucid sales to reduce the heat load on the AC? Also, running the A/C while charging to cool off the car should improve efficiency as it again reduces load on the car during travel. Swapping to the 19" wheels seems desirable if traveling through remote stretches of the country, potentially without cell service, and an increase to overall range.

While this not be financially reasonable, depending on the frequency of long trips, an upgrade to a GT would reduce a ton of headache and worry with the extra range. Less time at the chargers with further distance between stops.

These are things we will be looking into and doing if I end up in Arizona for a few months due to work. We have seen a decrease in efficiency during both very hot and very cold weather. Shades and tires seem like low hanging fruit plus cooling while charging the car.

 

[BS8899]

Sorry to revive such an old thread. Just did Orange County to Phoenix 3 weeks ago. Car was loaded with luggage and temps in OC were in the 70s. By Riverside it was 90 and traffic was horrible. By the Curacao Summit it was 100. By Quartzite, 104 the rest of the way. With all of the charging it took 12 hours. I was getting 2,5m/kwh. Half of the chargers were down and the rest always had 6 or more cars waiting. This made for some stressful miles. The return was worse but less waiting for chargers. I run 78 mph and usually get 3.3m/kwh. These are supposed to be cars and must function as such, climate system, lights and radio all on. My only concession is speed and that pisses me off. The general public will not tolerate this from cars. Temp on way haome was 108-105 whole way until West of Riverside. I got a whopping 2.2m/kwh. There are barely enough chargers across the dessert to do this with the non functional chargers.

I drive the route you drove many times. In the absence of unreasonable traffic, it should take about 6 hours. Your trip took 12 hours. I believe your dismal efficiency of 2.5 m/kWh vs your normal 3.3 m/kWh is mostly due to the traffic delay and resultant AC consumptions in the hot climate. In slow or stop-and-go traffic, I'd think an EV would fare better than an ICE car in energy consumption. The power consumed by AC in an EV sitting in 100F+ weather can be significant. 3.3m/kWh @78mph is respectable under normal circumstance.

 

[kort6776]

high temps have a minimal effect on range.

 

[kort6776]

I didn’t travel as far today and went 122 miles roundtrip, Pasadena to Malibu to Diamond Bar and home to Pasadena. Temps were between 90 and 105 the entire time topping out at 80 mph in some stretches, some Malibu stop and go traffic, some steady freeway. Cost me 40%. So that’s 3.465 mi/kwh. Obvi YMMV. Literally.

the 80 MPH affected the range far more than running the A/C

 

[BS8899]

the 80 MPH affected the range far more than running the A/C

@kort6776's comment RE: 80mph (vs 75mph or lower) affects the range more than AC i s correct.
In @joecrna's case where he was stuck in traffic and took an EXTRA 6hr for the trip from OC to PHX in 100F+ weather, the AC consumption can be significant. Unlike a small room in a house, the car, especially a Lucid with a glass canopy, is like a "hot-house". I don't know the AC capacity of the Lucid but I'd guess it is around 12,000-15,000BTU. Running this AC for 6 additional hours in 100F+ heat in a glass bubble can easily consume 20+kWh, which is a significant impact on the perceived efficiency of the mileage.

 

[JerseyStrong]

I drove from Jersey to GA and back with mountainous terrain in 95-100 degree weather @ 73 mph avg and racked up 4 m/kWh avg with air at 74 degrees. I bought the sunscreens which helped with interior comfort.

 

[BS8899]

I drove from Jersey to GA and back with mountainous terrain in 95-100 degree weather @ 73 mph avg and racked up 4 m/kWh avg with air at 74 degrees. I bought the sunscreens which helped with interior comfort.

I installed the Lucid sun screens in May 2024. While the Lucid screens are way over-priced, they do fit nicely, and yes, they make a noticeable difference. Since I live in Phoenix , and the summer temperature can approach 120F in the summer, it will make a tangible difference in the ability to cool the car. And on long drives, I also expect the sun screen will help with the AC, hence the power consumption and the efficiency.

 

[Pragmatic]

The car a/c is likely around 20,000 btu/hr for pull down. If 6800 btu/hr is required once the car is cool and at high ambient COP is only 2.0 (guess on my part). The car will need 1kw-hr for a/c. At 60 this will decrease efficiency by 0.02 (mile/kw-hr). The ac impact will be lower at high speeds and greater at low speeds. At 20 mph it will decrease efficiency by 0.05.

Heat being a larger delta T, will require more energy. If 6800 is needed for a 30F temperature then if it's 20F out side you'll need 12,000 btus to heat the car. At 60mph this will cost you 0.07 in efficiency. At 20 mph this would be 0.2.

None of this includes the energy hit to initially heat or cool the car. And my estimates of btus required could be off. But heating the should take 3.5 times more energy than cooling the car.

 

[Pragmatic]

The car a/c is likely around 20,000 btu/hr for pull down. If 6800 btu/hr is required once the car is cool and at high ambient COP is only 2.0 (guess on my part). The car will need 1kw-hr for a/c. At 60 this will decrease efficiency by 0.02 (mile/kw-hr). The ac impact will be lower at high speeds and greater at low speeds. At 20 mph it will decrease efficiency by 0.05.

Heat being a larger delta T, will require more energy. If 6800 is needed for a 30F temperature then if it's 20F out side you'll need 11,000 btus