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Would be nice to have those of you who have been fortunate enough to have received your Hummer EVs to share your driving experiences with those of us still anxiously salivating and awaiting arrival. Particularly interested in real world range especially at 75-80 mph highway speeds and also charging times and experiences. Thanks to everyone and enjoy those Hummers!
 

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We drove ~176 miles last night doing 10 over the limit from the EA station at Walterboro SC to Homewood Suites by Hilton Charlotte/Ayrsley, NC.
Left the EA station at 82% and arrived here with 15%. Google maps estimated we would arrive with 12% when we left the EA station. The range has met my expectations, but they were never "300 miles at 80 mph". On a long trip you pretty much have to depend on the 350kW stations. The 150 and 62.5/125 are too slow, unless you have a several hour activity.

It's quicker to drive faster if your spacing is right around 175 miles. Above that, I'm not sure. There is a big slow down in charge rate at 80%, was still only pulling 20kW when we got in to leave at 82%. It might kick up a bit after doing some balancing magic but I haven't actually observed that yet. We might today though, gap between CCS stations is 280 miles. If the hotel L2 isn't working tonight we will need all the range we can get.
 

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We drove ~176 miles last night doing 10 over the limit from the EA station at Walterboro SC to Homewood Suites by Hilton Charlotte/Ayrsley, NC.
Left the EA station at 82% and arrived here with 15%. Google maps estimated we would arrive with 12% when we left the EA station. The range has met my expectations, but they were never "300 miles at 80 mph". On a long trip you pretty much have to depend on the 350kW stations. The 150 and 62.5/125 are too slow, unless you have a several hour activity.

It's quicker to drive faster if your spacing is right around 175 miles. Above that, I'm not sure. There is a big slow down in charge rate at 80%, was still only pulling 20kW when we got in to leave at 82%. It might kick up a bit after doing some balancing magic but I haven't actually observed that yet. We might today though, gap between CCS stations is 280 miles. If the hotel L2 isn't working tonight we will need all the range we can get.
Wow, only pulling 20 kW at 82%? that is really bad, makes the top 20% of the battery unusable on a road trip. My E-Tron is still pulling 50 kW at 99%, and that is only a 95 kWh battery, so double the size in the Hummer should be able to take the charge twice as much for the same C rate. Sounds like GM has set up the Ultium batteries very conservative.
 

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Wow, only pulling 20 kW at 82%? that is really bad, makes the top 20% of the battery unusable on a road trip. My E-Tron is still pulling 50 kW at 99%, and that is only a 95 kWh battery, so double the size in the Hummer should be able to take the charge twice as much for the same C rate. Sounds like GM has set up the Ultium batteries very conservative.
I think it's a diagnostic thing because of the gaffe with the Bolt batteries.

*Currently at 93% pulling 36kW charge finish time went up by 15 minutes since we plugged in originally. It is 40F out here and windy.

1:48 to go from 44% to 100%
 

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I think it's a diagnostic thing because of the gaffe with the Bolt batteries.

*Currently at 93% pulling 36kW charge finish time went up by 15 minutes since we plugged in originally. It is 40F out here and windy.

1:48 to go from 44% to 100%
Interesting, 1:48 is a long time to add 184 miles. E-Tron by comparison goes 4-100% in 43 minutes (per Bjorn Nyland).

As thirsty as the Hummer is I think I would leave the charging station at 100kW and move on. As I previously expected the Hummer is going to challenging on road trips. More though, this info worries me about the Lyriq, as half the cells is usually half the charge rate. We have to wait and see, but it seems GM is not competitive with Tesla, Lucid, Hyundai, Porsche, and others with their brand new platform, not a good sign.

 

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Someone on the Rivian forums reported that it also drops the charge rate at 80% and then ramps it up again. Hyundai is also doing that because of the LG battery fire issue.

I have charged the new battery in my Bolt and it is not doing that, it is ramping down linearly as SoC increases. Some people have gotten a temporary software fix in the Bolt with the old battery and it stop charging at 80% and does some checks. But the limit for the old battery is stuck at 80% in that case. I wonder if GM was worried about the LG batteries initially in the Hummer and had some of that monitor software in there initially.
 

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Interesting, 1:48 is a long time to add 184 miles. E-Tron by comparison goes 4-100% in 43 minutes (per Bjorn Nyland).

As thirsty as the Hummer is I think I would leave the charging station at 100kW and move on. As I previously expected the Hummer is going to challenging on road trips. More though, this info worries me about the Lyriq, as half the cells is usually half the charge rate. We have to wait and see, but it seems GM is not competitive with Tesla, Lucid, Hyundai, Porsche, and others with their brand new platform, not a good sign.

65% is about the sweet spot for charging but up to 75 is still pretty quick. Normally I'd never stay on a fast charger passed 80%. BUT, even upon hitting 100%, Google maps was still saying we weren't going to make it to the next charging station. The Energy estimator in the GM app said -2%. We're stopping at a hotel overnight that has a charger but that's never a guarantee that it'll work nor be available.

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Someone on the Rivian forums reported that it also drops the charge rate at 80% and then ramps it up again. Hyundai is also doing that because of the LG battery fire issue.

I have charged the new battery in my Bolt and it is not doing that, it is ramping down linearly as SoC increases. Some people have gotten a temporary software fix in the Bolt with the old battery and it stop charging at 80% and does some checks. But the limit for the old battery is stuck at 80% in that case. I wonder if GM was worried about the LG batteries initially in the Hummer and had some of that monitor software in there initially.
Hyundai is using SK batteries on the E-GMP platform, they sh-- canned LG chem after their Kona recall. GM was in too deep with LG or they likely would have done the same.


Rivian charges fast to 70%, then falls off dramatically, It seems nobody has the guts of Audi when it comes to a flat charging curve.
 

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Hyundai is using SK batteries on the E-GMP platform, they sh-- canned LG chem after their Kona recall. GM was in too deep with LG or they likely would have done the same.


Rivian charges fast to 70%, then falls off dramatically, It seems nobody has the guts of Audi when it comes to a flat charging curve.
Kyle seems to think the Rivian charge drops are due to thermal issues, based on his tests. One of his plots shows a dip at about 70-75% and I think that is what some owners also reported. It is unusual to see the charge rate drop, then climb again. His plot shows the big taper starting at 58%.

The Mach E and ID4 are relatively flat to 80%, as compared to most of the other ones. The big buffer in the Etron helps to maintain the high rate longer. Actually the old Chevy Sparks held a high C rate to at least 90%, but those batteries are famous for degradation. GM likely learned something from that.
 

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Kyle seems to think the Rivian charge drops are due to thermal issues, based on his tests. One of his plots shows a dip at about 70-75% and I think that is what some owners also reported. It is unusual to see the charge rate drop, then climb again. His plot shows the big taper starting at 58%.

The Mach E and ID4 are relatively flat to 80%, as compared to most of the other ones. The big buffer in the Etron helps to maintain the high rate longer. Actually the old Chevy Sparks held a high C rate to at least 90%, but those batteries are famous for degradation. GM likely learned something from that.
Yes, Kyle thought the battery in the Rivian is too cold to draw the full charge rate, and mentioned the ambient temperature was in the 30's, We need better information on the Rivian this spring, but Clearly the Rivian adds miles faster then the Hummer EV, which is worst in class for road tripping due to its mediocre charging, and atrocious efficiency.

Have you noticed a trend online, nearly everyone who has gotten their HummerEV is putting them up for sale? I don't think we are seeing people sell them because they love them so much.

Interesting thought on degradation, Our E-Tron has more range and battery capacity than it did when it was new. I think Audi just struck the right balance in thermal management and starts with a low peak rate so it can hold through the charging cycle.
 

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We drove ~176 miles last night doing 10 over the limit from the EA station at Walterboro SC to Homewood Suites by Hilton Charlotte/Ayrsley, NC.
Left the EA station at 82% and arrived here with 15%. Google maps estimated we would arrive with 12% when we left the EA station. The range has met my expectations, but they were never "300 miles at 80 mph". On a long trip you pretty much have to depend on the 350kW stations. The 150 and 62.5/125 are too slow, unless you have a several hour activity.

It's quicker to drive faster if your spacing is right around 175 miles. Above that, I'm not sure. There is a big slow down in charge rate at 80%, was still only pulling 20kW when we got in to leave at 82%. It might kick up a bit after doing some balancing magic but I haven't actually observed that yet. We might today though, gap between CCS stations is 280 miles. If the hotel L2 isn't working tonight we will need all the range we can get.
Dang, @Dark-Fx, you came right through my neck of the woods.... I would have loved to catch a glimpse of your Hummer... I live in Columbia, and you went right past my dealership on your way to Charlotte...
 

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So Dark-fx, it sounds like you were going 80 mph with an elevation gain of around 700 ft for 176 miles and used two-thirds of the battery? That actually seems quite good, especially with the aerodynamics of the Hummer at that speed. Most of the online range testing is with zero elevation gain and 70 mph and that should produce a significantly better result.
 

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So Dark-fx, it sounds like you were going 80 mph with an elevation gain of around 700 ft for 176 miles and used two-thirds of the battery? That actually seems quite good, especially with the aerodynamics of the Hummer at that speed. Most of the online range testing is with zero elevation gain and 70 mph and that should produce a significantly better result.
Today's result was a bit worse. Headwinds and accumulation on the freeway in some spots. Lowest temp I saw was 23F. Still was able to do 400 miles in a hair under 7 hours starting with a 65% charge. Estimate from Energy Assist was 7:41 including charging.
 

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Today's result was a bit worse. Headwinds and accumulation on the freeway in some spots. Lowest temp I saw was 23F. Still was able to do 400 miles in a hair under 7 hours starting with a 65% charge. Estimate from Energy Assist was 7:41 including charging.
Yes I traveled from KY to MI today and the winds were relentless.

According to the EPA MPGe figures in Car and Driver, the highway range for the Hummer should be 301 miles. Your original trip would have worked out to be 262 for the whole pack, which again, for those conditions seems good. An R1T with 20 inch tires should have around 252 miles of EPA highway range based on Rivian's guidance on the tire selection, and C&D got 220 miles at 75 mph with no net elevation change. That's about the same percent less as your result.
 

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Yes I traveled from KY to MI today and the winds were relentless.

According to the EPA MPGe figures in Car and Driver, the highway range for the Hummer should be 301 miles. Your original trip would have worked out to be 262 for the whole pack, which again, for those conditions seems good. An R1T with 20 inch tires should have around 252 miles of EPA highway range based on Rivian's guidance on the tire selection, and C&D got 220 miles at 75 mph with no net elevation change. That's about the same percent less as your result.
Kyle Connor tested the Rivian with 20's at 70, it went 289.3 miles in a loop at 70 mph
 

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Kyle Connor tested the Rivian with 20's at 70, it went 289.3 miles in a loop at 70 mph
Yes, I saw that. I wanted to compare the test closest to Dark-fx's speed. I do find it hard to reconcile C&D highway tests with other outlets sometimes. Air resistance goes up by the square of speed, but their results are sometimes much lower than a 5 mph difference should make.
 

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Yes, I saw that. I wanted to compare the test closest to Dark-fx's speed. I do find it hard to reconcile C&D highway tests with other outlets sometimes. Air resistance goes up by the square of speed, but their results are sometimes much lower than a 5 mph difference should make.
Ya, I think we have to wait for Kyle to get a Hummer to test in similar conditions and parameters. There will always be some that see better or worse result, but consistent test methods are critical to draw anything from the data.
 

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Ya, I think we have to wait for Kyle to get a Hummer to test in similar conditions and parameters. There will always be some that see better or worse result, but consistent test methods are critical to draw anything from the data.
I offered him mine. He seemed interested but stopped following up on it. Could be related to the press embargo from the GM event.
 

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Kyle Connor tested the Rivian with 20's at 70, it went 289.3 miles in a loop at 70 mph
The problem with all of Kyle's tests out of Fort Collins is the loop he drives averages 5,000 feet above sea level. The air is about 20% less dense than sea level, reducing effective net aero drag CdA proportionally. The net range effect is consistently 10% more range than equivalent tests at or near sea level, which is the basis for standard EPA dyno aero drag factors and most tests by others who play the range game like Tom or Bjorn at the same average speed..
 
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