Gravity 75 mph Range

[WeighingGravity]

Yes, thanks for the clarification. That is part of why I said "duh" because he literally clarified it in the first part of the same sentence. My kid is taking the PSAT today and it's a good thing it's her and not me because my reading comprehension apparently is at a primary school level today.

 

[Knucklehead]

There are various threads regarding range testing. So far, I have yet to see a test at anything faster than 70 mph. At 70 mph, it seems like an efficiency of 3.0 mi/kWh is achievable. It may be possible to do better in the right conditions.

It seems many forum members with Gravities are reporting efficiencies in that range at highway speeds as well. My guess is 3.0 mi/kWh at 75 mph will be hard to achieve and it is very unlikely to hit that level of efficiency at 80 mph. (I am really looking forward to OOS's 10% challenge to see how the Gravity does at 80 mph.)

Since I think we have a good estimate for maximum efficiency, the key then is: how much battery capacity is available? It has been well understood that 121 kWh is the useable capacity. But how much of that "usable" capacity is below 0%? Technically if you drive it below 0% and it is still moving, that is "usable". Tesla uses this trick to meet their range numbers.

If the gravity has 6 kWh of buffer below 0%, then that means it has 115 kWh of capacity until it hits 0%. 115*3 = 345 miles.

When driving to when the car stops: 121*3 = 363 miles.

This is probably best case. At 75, I bet real world efficiency is probably closer to 2.8 or 2.9. It may be possible to hit that level of efficiency at 80. Maybe, especially if there are some slowdowns mixed in with the 80-mph cruising.

 

[dbsb3233]

There are various threads regarding range testing. So far, I have yet to see a test at anything faster than 70 mph. At 70 mph, it seems like an efficiency of 3.0 mi/kWh is achievable. It may be possible to do better in the right conditions.

It seems many forum members with Gravities are reporting efficiencies in that range at highway speeds as well. My guess is 3.0 mi/kWh at 75 mph will be hard to achieve and it is very unlikely to hit that level of efficiency at 80 mph. (I am really looking forward to OOS's 10% challenge to see how the Gravity does at 80 mph.)

Since I think we have a good estimate for maximum efficiency, the key then is: how much battery capacity is available? It has been well understood that 121 kWh is the useable capacity. But how much of that "usable" capacity is below 0%? Technically if you drive it below 0% and it is still moving, that is "usable". Tesla uses this trick to meet their range numbers.

If the gravity has 6 kWh of buffer below 0%, then that means it has 115 kWh of capacity until it hits 0%. 115*3 = 345 miles.

When driving to when the car stops: 121*3 = 363 miles.

This is probably best case. At 75, I bet real world efficiency is probably closer to 2.8 or 2.9. It may be possible to hit that level of efficiency at 80. Maybe, especially if there are some slowdowns mixed in with the 80-mph cruising.

I really wanna see an 80 MPH range test. Nearly half of my frequent Denver-Vegas drive is 80 MPH (thru Utah). In my AWD Mach-E, I would usually average 2.8 for the entire round-trip (a mix of 80, 75, and some 65 thru the mountains). A few of those 80 MPH Utah legs would fall all the way to 2.2-2.4.

If we're lucky to get 3.0 in the Gravity at 70, I'm guessing 80 may drop it to ~2.4. If usable battery (above 0%) is roughly 117 kWh, that's 280 range (196 for 10-80%).

 

[electric]

I really wanna see an 80 MPH range test. Nearly half of my frequent Denver-Vegas drive is 80 MPH (thru Utah). In my AWD Mach-E, I would usually average 2.8 for the entire round-trip (a mix of 80, 75, and some 65 thru the mountains). A few of those 80 MPH Utah legs would fall all the way to 2.2-2.4.

If we're lucky to get 3.0 in the Gravity at 70, I'm guessing 80 may drop it to ~2.4. If usable battery (above 0%) is roughly 117 kWh, that's 280 range (196 for 10-80%).

Not exactly scientific data, but I live in Sierra Nevada Foothills with significant, but not crazy elevation changes, and usually drive with speeds mix as you described above.
I had my Gravity GT with 22/23 wheel package for a month now, with 1655 miles driven and total efficiency of 2.63.
My battery is reporting 117kWh usable.

 

[Knucklehead]

I really wanna see an 80 MPH range test. Nearly half of my frequent Denver-Vegas drive is 80 MPH (thru Utah). In my AWD Mach-E, I would usually average 2.8 for the entire round-trip (a mix of 80, 75, and some 65 thru the mountains). A few of those 80 MPH Utah legs would fall all the way to 2.2-2.4.

If we're lucky to get 3.0 in the Gravity at 70, I'm guessing 80 may drop it to ~2.4. If usable battery (above 0%) is roughly 117 kWh, that's 280 range (196 for 10-80%).

I hope it is better than that. I frequently am able to achieve 2.4 mi/kWh in my Tri Max R1T with an average speed of 75-80. There is usually some slower traffic mixed in, which really helps pull up the efficiency. But I often see 2.4 with when my average speed is between 75 and 80. That said, just the slightly colder weather recently has had a noticeable impact.

 

[dbsb3233]

I hope it is better than that. I frequently am able to achieve 2.4 mi/kWh in my Tri Max R1T with an average speed of 75-80. There is usually some slower traffic mixed in, which really helps pull up the efficiency. But I often see 2.4 with when my average speed is between 75 and 80. That said, just the slightly colder weather recently has had a noticeable impact.

I hope it's better too, but I find myself lowering expectations for Gravity range by the week. Not only does the advertised 450 combined look like a total pipe dream, simply reaching the 400's looks unlikely (albeit only limited test results so far). Hope it improves but I'm not very optimistic anymore.

I've got the 450 trim on order (5-seat 20/21s). 450 sounds more like 370. Which is still good for it's size, but feels like we were misled with the 450 number.

 

[Ron_Burgundy]

70+ kills range. Period. I think it’s unrealistic to expect “good” range on any EV at that speed. I know OOS has done tests but as noted on other threads, doing it at altitude is not realistic. But, with perfect conditions you may be able to get 3.0 at 75mph.

It’s easy to get 3.30+ (which is the rated range efficiency) on the highway but you can’t go above 70 and you need good conditions.

Much like I don’t understand some folks’ fixation on track performance, I do not quite understand why people are focused on efficiency at 75mph. I have been on CA highways and in the southeast - I know folks go fast, so is that the issue/reason focus on the 75mph range?

I love spirited driving, but when I drive that way, I know it’s not efficient and that’s okay.

 

[Knucklehead]

70+ kills range. Period. I think it’s unrealistic to expect “good” range on any EV at that speed. I know OOS has done tests but as noted on other threads, doing it at altitude is not realistic. But, with perfect conditions you may be able to get 3.0 at 75mph.

It’s easy to get 3.30+ (which is the rated range efficiency) on the highway but you can’t go above 70 and you need good conditions.

Much like I don’t understand some folks’ fixation on track performance, I do not quite understand why people are focused on efficiency at 75mph. I have been on CA highways and in the southeast - I know folks go fast, so is that the issue/reason focus on the 75mph range?

I love spirited driving, but when I drive that way, I know it’s not efficient and that’s okay.

I think the fixation is because 75 mph is a common average speed for highway travel. Personally I set the cruise to 79 mph and only slow down when traffic is in the way, or the speed limit drops. Traffic sometimes lowers my average speed to below 75, and sometimes it is higher.

Understanding how well the Gravity does at 75 is relevant when trying to determine how far you can drive on the highway before you have to stop to charge. At least if you drive like me.

If you live out west where 80 mph speed limits are more common, at least the 75 mph estimate helps get an idea. But 80+ mph testing would be better for those people.

 

[SpaceGhost]

70+ kills range. Period. I think it’s unrealistic to expect “good” range on any EV at that speed. I know OOS has done tests but as noted on other threads, doing it at altitude is not realistic. But, with perfect conditions you may be able to get 3.0 at 75mph.

It’s easy to get 3.30+ (which is the rated range efficiency) on the highway but you can’t go above 70 and you need good conditions.

Much like I don’t understand some folks’ fixation on track performance, I do not quite understand why people are focused on efficiency at 75mph. I have been on CA highways and in the southeast - I know folks go fast, so is that the issue/reason focus on the 75mph range?

I love spirited driving, but when I drive that way, I know it’s not efficient and that’s okay.

For context, it's not really a fixation or thrill seeking. In California for example, it's common to drive from the bay area to tahoe which ranges from 200-250 miles. Those routes are about 70% highway where the average speed is 75 and the common speed of most traffic is 80 for sure. Driving in the flow is to drive 80 mph, which I've always found safer than having everyone pass you. Now, the whole trip isn't 80 and once off the highway the trip is more at speed limit or 5 over. That said, the challenge with that trip is that you go from sea level up and over 2 7k altitude passes, and in the winter, it's cold.

Off of peak traffic times, it's a trip that takes 3 hours 15 minutes and it's nice to just get there and get settled in, versus stopping and turning it into a 4 hour + trip.

 

[dbsb3233]

70+ kills range. Period. I think it’s unrealistic to expect “good” range on any EV at that speed. I know OOS has done tests but as noted on other threads, doing it at altitude is not realistic. But, with perfect conditions you may be able to get 3.0 at 75mph.

It’s easy to get 3.30+ (which is the rated range efficiency) on the highway but you can’t go above 70 and you need good conditions.

Much like I don’t understand some folks’ fixation on track performance, I do not quite understand why people are focused on efficiency at 75mph. I have been on CA highways and in the southeast - I know folks go fast, so is that the issue/reason focus on the 75mph range?

I love spirited driving, but when I drive that way, I know it’s not efficient and that’s okay.

No one expects full EPA at highways speeds, of course. The question is not IF there will be loss at highway speeds, but rather HOW MUCH. There's a significant difference between 10% vs 20% vs 25%+.

The reason we care about 75 MPH is because in most of the country, that's the more typical road trip interstate speed. Some people drive below the speed limit but in practical terms, most drivers will be going at or above the speed limit. West of the Mississippi, 75 is the common interstate speed limit (with a few 80's). East it's usually 70, but most are still driving ~75. It's simply the more common road trip speed.

70 is still a good baseline measure to have (we'll take any baseline we can get), but 75 is more realistic for a road trip IMO.

And of course the fact that Lucid touts 450 miles on the Gravity (a "wow!" number that gets a lot of attention) along with their reputation for world-class efficiency means they set themselves up for extra range scrutiny. It's arguably their biggest selling point.

 

[Knucklehead]

And of course the fact that Lucid touts 450 miles on the Gravity (a "wow!" number that gets a lot of attention) along with their reputation for world-class efficiency means they set themselves up for extra range scrutiny. It's arguably their biggest selling point.

Range and charging speed. They certainly delivered on the charging speed selling point.

 

[dbsb3233]

For context, it's not really a fixation or thrill seeking. In California for example, it's common to drive from the bay area to tahoe which ranges from 200-250 miles. Those routes are about 70% highway where the average speed is 75 and the common speed of most traffic is 80 for sure. Driving in the flow is to drive 80 mph, which I've always found safer than having everyone pass you. Now, the whole trip isn't 80 and once off the highway the trip is more at speed limit or 5 over. That said, the challenge with that trip is that you go from sea level up and over 2 7k altitude passes, and in the winter, it's cold.

Off of peak traffic times, it's a trip that takes 3 hours 15 minutes and it's nice to just get there and get settled in, versus stopping and turning it into a 4 hour + trip.

That's us too. Most of our routes have 75 or 80 MPH speed limits. On an 80 SL, I usually just set it at 80. On a 75 SL, I usually set it to 78.

We do long drives, but we try to stick to daylight. 11-12 hours is about our max for a day. Some of our drives are right at the tipping point where an extra hour or two would push us into splitting it into a 2 day drive (which means an extra day each way, extra cost for hotels, etc). The more charging stops we can shave off, the better chance we can squeeze it into a comfortable 1-day window. Even though the Gravity charges fast, every extra stop still adds "churn" time just getting on/off the highway and to the station (some of which aren't right off the interstate).

For something like an 800 mile drive, an EV needing 5-stops with lower range usually means breaking the drive into 2 days. But one that has really long range can usually do it same-day. That's my #1 motivation for getting a Gravity (along with other reasons). It *should* be a significant range upgrade over our Macan, which is a significant range upgrade over our Mach-E. Hoping it can approach ICE-equivalency (just 2 refueling stops for 800 miles).

 

[Ron_Burgundy]

No one expects full EPA at highways speeds, of course. The question is not IF there will be loss at highway speeds, but rather HOW MUCH. There's a significant difference between 10% vs 20% vs 25%+.

The reason we care about 75 MPH is because in most of the country, that's the more typical road trip interstate speed. Some people drive below the speed limit but in practical terms, most drivers will be going at or above the speed limit. West of the Mississippi, 75 is the common interstate speed limit (with a few 80's). East it's usually 70, but most are still driving ~75. It's simply the more common road trip speed.

70 is still a good baseline measure to have (we'll take any baseline we can get), but 75 is more realistic for a road trip IMO.

And of course the fact that Lucid touts 450 miles on the Gravity (a "wow!" number that gets a lot of attention) along with their reputation for world-class efficiency means they set themselves up for extra range scrutiny. It's arguably their biggest selling point.

Got it. Makes sense.

I think, if you’re a Tahoe traveler, for example, elevation and low temps (in winter) will kill your range more than going 75mph. I found elevation alone, going from about 250 to 3,000 (which is high for the East Coast!) really impacts my range a lot more than speed. At least, in our R1S and X. I’d expect the same for Gravity.

Based on my drives this weekend, I do think one could get about 90% of rated range at 75mph in Gravity with 20/21 or 21/22, but you’d need 50-65 degrees, not a lot of elevation, no rain, A/S tires, aero covers, etc.

If you have the 22/23 performance, I think there’s little/no chance of getting 90%. Will be interesting to hear from folks.

 

[dbsb3233]

Got it. Makes sense.

I think, if you’re a Tahoe traveler, for example, elevation and low temps (in winter) will kill your range more than going 75mph. I found elevation alone, going from about 250 to 3,000 (which is high for the East Coast!) really impacts my range a lot more than speed. At least, in our R1S and X. I’d expect the same for Gravity.

Based on my drives this weekend, I do think one could get about 90% of rated range at 75mph in Gravity with 20/21 or 21/22, but you’d need 50-65 degrees, not a lot of elevation, no rain, A/S tires, aero covers, etc.

If you have the 22/23 performance, I think there’s little/no chance of getting 90%. Will be interesting to hear from folks.

Oh absolutely. Significant elevation gain (or loss) from one end of a leg to the other makes a huge impact. So do freezing temps. But it's not an either-on, it's cumulative. Each one of those things adds up, on top of the speed loss. First we have to establish the baseline for what the Gravity will do at highway speed in good conditions, then subtract further for any bad condition losses (elevation gain, cold temps, wind, wet road, extra weight in the car, etc.).

In ideal conditions (70F+ temps, no significant net elevation change, no wind, dry roads, etc), if I'm getting 20% below EPA at 70 MPH, I know that's about as good as it's gonna get. Then I'll subtract further for each addition adverse condition.

 

[TahoeMichael]

Got it. Makes sense.

I think, if you’re a Tahoe traveler, for example, elevation and low temps (in winter) will kill your range more than going 75mph. I found elevation alone, going from about 250 to 3,000 (which is high for the East Coast!) really impacts my range a lot more than speed. At least, in our R1S and X. I’d expect the same for Gravity.

Based on my drives this weekend, I do think one could get about 90% of rated range at 75mph in Gravity with 20/21 or 21/22, but you’d need 50-65 degrees, not a lot of elevation, no rain, A/S tires, aero covers, etc.

If you have the 22/23 performance, I think there’s little/no chance of getting 90%. Will be interesting to hear from folks.

Raising a GGT from sea level to the ~6400' altitude of Lake Tahoe consumes just a bit under 15 kWh (I think I'm getting the math right) beyond what the driving distance would consume if the trip were flat, and ignoring any inefficiency from going up-and-down and imperfect regen recapturing energy. If you're driving at a speed that would get you 3 miles/kWh going flat, then you lose about 45 miles of range, or about 13% charge (actually more, given that it won't be perfectly efficient). At least, that's what physics would tell us. I'm interested to give it a try and see what actually occurs.

 

[hwy17er]

Gotta say I love the all left brained analysis from all the enginerical posters on here
Well thought out theoretics in excited expectation of good hard data to come!

 

[borski]

For context, it's not really a fixation or thrill seeking. In California for example, it's common to drive from the bay area to tahoe which ranges from 200-250 miles. Those routes are about 70% highway where the average speed is 75 and the common speed of most traffic is 80 for sure. Driving in the flow is to drive 80 mph, which I've always found safer than having everyone pass you. Now, the whole trip isn't 80 and once off the highway the trip is more at speed limit or 5 over. That said, the challenge with that trip is that you go from sea level up and over 2 7k altitude passes, and in the winter, it's cold.

Off of peak traffic times, it's a trip that takes 3 hours 15 minutes and it's nice to just get there and get settled in, versus stopping and turning it into a 4 hour + trip.

I literally just made that trip and didn’t even need to charge once. I charged on the way home. And I don’t drive to hypermile.

 

[illopp00]

70+ kills range. Period. I think it’s unrealistic to expect “good” range on any EV at that speed. I know OOS has done tests but as noted on other threads, doing it at altitude is not realistic. But, with perfect conditions you may be able to get 3.0 at 75mph.

It’s easy to get 3.30+ (which is the rated range efficiency) on the highway but you can’t go above 70 and you need good conditions.

Much like I don’t understand some folks’ fixation on track performance, I do not quite understand why people are focused on efficiency at 75mph. I have been on CA highways and in the southeast - I know folks go fast, so is that the issue/reason focus on the 75mph range?

I love spirited driving, but when I drive that way, I know it’s not efficient and that’s okay.

I have yet to find a location in the US where you can travel at 70-75mph for an actual 350 miles straight. Just do the math from Google Maps on your distance divided by ETA and your average speed is nowhere near 75.

 

[Ron_Burgundy]

I have yet to find a location in the US where you can travel at 70-75mph for an actual 350 miles straight. Just do the math from Google Maps on your distance divided by ETA and your average speed is nowhere near 75.

This was kind of my point. Running the car from 100% to 0% at 75mph doesn’t actually tell me anything. Not especially realistic. But that’s okay as I don’t need the information and it appears others find it valuable.

 

[illopp00]

That's us too. Most of our routes have 75 or 80 MPH speed limits. On an 80 SL, I usually just set it at 80. On a 75 SL, I usually set it to 78.

We do long drives, but we try to stick to daylight. 11-12 hours is about our max for a day. Some of our drives are right at the tipping point where an extra hour or two would push us into splitting it into a 2 day drive (which means an extra day each way, extra cost for hotels, etc). The more charging stops we can shave off, the better chance we can squeeze it into a comfortable 1-day window. Even though the Gravity charges fast, every extra stop still adds "churn" time just getting on/off the highway and to the station (some of which aren't right off the interstate).

For something like an 800 mile drive, an EV needing 5-stops with lower range usually means breaking the drive into 2 days. But one that has really long range can usually do it same-day. That's my #1 motivation for getting a Gravity (along with other reasons). It *should* be a significant range upgrade over our Macan, which is a significant range upgrade over our Mach-E. Hoping it can approach ICE-equivalency (just 2 refueling stops for 800 miles).

I did this during the summer with my Air Touring and it was 3 charge stops during breakfast, lunch and dinner. ~10-85% and 240-mile stints at 5-10 above speed limits. I figure a Gravity Touring will do the exact same mph charge rate since it charges faster but is less efficient.