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Is the Hummer EV's Ultium battery inefficicent?

4322 Views 8 Replies 4 Participants Last post by StillHummer, Oct 22, 2020

Oakwood

Discussion Starter · Oct 22, 2020

InsideEVs did a deep dive into the Hummer's batter pack and looked at how efficient its battery pack is. Particularly with the Edition 1. They're arguing that for a 200 kWh battery pack the Hummer should have way more range than 350 miles.

Of course the Hummer's weight has a role in this but they might be on to something. What does everyone think of the Hummer's reported range. Maybe GM is underpromising here with 350+ miles?

GMC Hummer EV Battery Is Over 200 kWh, But Range Is Only 350 Miles: Why?

The recently unveiled GMC Hummer EV is an all-electric high-end pickup truck, but one thing seems to be a concern - the range of up to 350+ miles.

insideevs.com

Assuming 200 kWh (the pack capacity was not announced), 350 miles means 571 Wh/mi (355 Wh/km), even before towing anything.

According to the Engineering Explained video (see below from about 14:25), the GMC Hummer EV will be equipped with over a 200 kWh battery pack (GM's representatives reportedly hinted at it, but later told us that the figure is not confirmed).

The truck will be equipped with Ultium Cells batteries - 24 modules, 24 cells each (total of 576 pouch cells).

Assuming Engineering Explained's number that a single cell has a capacity of 100 Ah, we can estimate the pack's nominal capacity simply by assuming the nominal voltage of the cells:

at 3.5 V: 201.6 kWh
at 3.6 V: 207.4 kWh
at 3.7 V: 213.1 kWh
at 3.8 V: 218.9 kWh

We guess that something around 215 kWh with 200 kWh usable would be a fair number.

One of the most interesting things about GM's battery approach is wireless communication between the modules.

The 800 V battery system is ready to charge at up to 350 kW of power (from DC fast chargers). In about 10 minutes, some 100 miles (160 km) out of the total 350 miles range, could be replenished in the top of the line version.

100 miles is 28.5% of the total range, while the 10 minutes at 350 kW peak would translate into roughly 58 kWh. The 100% range would then be 204 kWh (probably less, as we doubt the ability to stick to 350 kW for the entire 10 minutes).

Anyway, also this way we end with a conclusion that the pack is around 200 kWh usable.

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StillHummer

· #2 · Oct 22, 2020

Excellent analysis, @Oakwood. That was very helpful info to lay out.

I think the shape definitely has a lot to do with why it won't go 500 miles on a charge...but I also FIRMLY believe that GM is purposely sandbagging these numbers.

When we heard about the release during the Super Bowl in February, and later in March at EV day, GM said that the batteries would cap out at 400 miles. Logically, you have to assume that's for the big boy, 200 kWh pack, which the Hummer has.

Every trim says a BASE number for range..."350+ miles"..."300+ miles"...etc.

I'm thinking that the range on all of them will be higher, and the range on the Edition One will be close to 400 miles. Not class-leading, but for what it is, still excellent.

And don't forget, the way Ultium works, the modules can be swapped out in the future for much improved modules that offer superior range and life. We could be seeing 600 mile Hummer EV's by the end of the decade, easily. Some will come like that off the factory floor, and old ones will take the module swap to keep up.

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Tom E-Tron

· #3 · Oct 22, 2020

StillHummer said:
Excellent analysis, @Oakwood. That was very helpful info to lay out.

I think the shape definitely has a lot to do with why it won't go 500 miles on a charge...but I also FIRMLY believe that GM is purposely sandbagging these numbers.

When we heard about the release during the Super Bowl in February, and later in March at EV day, GM said that the batteries would cap out at 400 miles. Logically, you have to assume that's for the big boy, 200 kWh pack, which the Hummer has.

Every trim says a BASE number for range..."350+ miles"..."300+ miles"...etc.

I'm thinking that the range on all of them will be higher, and the range on the Edition One will be close to 400 miles. Not class-leading, but for what it is, still excellent.

And don't forget, the way Ultium works, the modules can be swapped out in the future for much improved modules that offer superior range and life. We could be seeing 600 mile Hummer EV's by the end of the decade, easily. Some will come like that off the factory floor, and old ones will take the module swap to keep up.

The battery is indeed 200 kWh, and GM is slightly understating range, I am guessing 375-400 will be the EPA range, having 8 years experience with EV's from Tesla S to my current E-Tron I think the realistic EPA wh/mi is going to be 500-550 for this truck. I think the truck will weigh just under 7K lbs empty, hence 8 lug wheels. I reserved one, and will be fun to see developments as the final production model comes into focus.

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StillHummer

· #4 · Oct 22, 2020

Tom E-Tron said:
The battery is indeed 200 kWh, and GM is slightly understating range, I am guessing 375-400 will be the EPA range, having 8 years experience with EV's from Tesla S to my current E-Tron I think the realistic EPA wh/mi is going to be 500-550 for this truck. I think the truck will weigh just under 7K lbs empty, hence 8 lug wheels. I reserved one, and will be fun to see developments as the final production model comes into focus.

Great to have a former Tesla owner (recovering? lol, I kid) on the forums, welcome, @Tom E-Tron! Adding to our diverse membership in terms of vehicle background.

I'm curious as to why you think 500 miles or range is possible? What more than the weight and kWh's led you to that conclusion? I'm not saying you're wrong at all, in fact I'm curious because I really hope you're right. That'd be amazing.

What Hummer EV model did you reserve? And how do you like the E-Tron?

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Oakwood

Discussion Starter · #5 · Oct 22, 2020

Tom E-Tron said:
The battery is indeed 200 kWh, and GM is slightly understating range, I am guessing 375-400 will be the EPA range, having 8 years experience with EV's from Tesla S to my current E-Tron I think the realistic EPA wh/mi is going to be 500-550 for this truck. I think the truck will weigh just under 7K lbs empty, hence 8 lug wheels. I reserved one, and will be fun to see developments as the final production model comes into focus.

Welcome @Tom E-Tron! If they can get 375-400 miles from the EPA that'd be a huge win since their ratings are so stingy.

I think the EPA rating will be lower but people will be getting that 375-400 miles of range on their own.

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Tom E-Tron

· #6 · Oct 22, 2020

Oakwood said:
Welcome @Tom E-Tron! If they can get 375-400 miles from the EPA that'd be a huge win since their ratings are so stingy.

I think the EPA rating will be lower but people will be getting that 375-400 miles of range on their own.

StillHummer said:
Great to have a former Tesla owner (recovering? lol, I kid) on the forums, welcome, @Tom E-Tron! Adding to our diverse membership in terms of vehicle background.

I'm curious as to why you think 500 miles or range is possible? What more than the weight and kWh's led you to that conclusion? I'm not saying you're wrong at all, in fact I'm curious because I really hope you're right. That'd be amazing.

What Hummer EV model did you reserve? And how do you like the E-Tron?

I reserved the Edition 1, E-Tron is the best car I have ever owned by a long shot. Comfortable, bank vault quiet, full of cool features, and fun to drive, very surprising when you put it in "Dynamic" mode and push it on a winding road. Good range, and charges very fast, it was a major upgrade from our Tesla.

I do not think the Hummer will have 500 miles of range, I think the consumption will be 500-550 wh/mi watt hours / per mile, which calculates to 375 to 400 miles of range. Of course on a flat country road at 35-50 MPH 500 miles might be a long shot possibility. The Hummer EV is going to have very high consumption at freeway speeds, and if you drive it over the speed limit on the motorway, you will not go far between charges.

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Tom E-Tron

· #7 · Oct 22, 2020

Oakwood said:
Welcome @Tom E-Tron! If they can get 375-400 miles from the EPA that'd be a huge win since their ratings are so stingy.

I think the EPA rating will be lower but people will be getting that 375-400 miles of range on their own.

Hi, Wow, you guys reply quick... When GM quoted the 350+ mile range they were referring to where they think the EPA estimate is going to be. On Bolt they quoted 200 miles, and when it came to production was 238 miles EPA, so I expect they are slightly sandbagging. GM is not likely to oversell, and then under deliver. The EPA rating is not everything, and not all EPA ratings are created equal, for example on our E-Tron with a wimpy 204 mile EPA range, we have always been able to beat that even at freeway speed 60-70+ mph on a road trip. On our Tesla we had before the E-Tron had a 270 mile EPA range, but was never able to achieve that on a road trip, we saw 220-230 miles which is right about what we get from our E-Tron.

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AllTerrain

· #8 · Oct 22, 2020

@Tom E-Tron fun fact, the HUMMER EV will be more efficient than a Prius, on paper, with current numbers at least. I can only imagine how much better it'll get in real world testing.

As for that Prius claim... it makes sense...

Let me address an elephant in the room. EV nerds are quick to point out that the GMC Hummer EV “only” gets 350+ miles out of a ~200kWh battery. Compared to their tiny little low-rolling-resistance aero optimized hypermiling penalty box sedan, SURE. But...
The new 700 hp Ram TRX is expected to achieve an 11 mpg city / 17 mpg highway EPA rating... 13 mpg EPA combined. That’s actually not too bad considering what the original Hummer H2 earned.
The GMC Hummer EV Edition 1 makes 1,000 horsepower. It has large 35” tires. It’s as wide as a Raptor. It’s massively capable off road. And it’s expected to earn a combined range of 350+ miles from that ~200 kWh battery pack. Keep with me...
The EPA has a formula for “mpg equivalency” (mpge). They estimate that burning a gallon of gasoline has the potential energy of 115,000 btus. That’s the equivalent potential energy of 33.7 kWh. So to earn 100 mpge, an EV with a 33.7 kWh battery pack would need to have a 100 mile combined EPA range.
By that official formula, the GMC Hummer EV earns a... 59+ miles per gallon rating
Let that sink in — a 1,000 hp supertruck with the apparent aero of a small house, with a 50° approach angle (in extraction mode) and huge all terrain tires... is MORE efficient than a Prius. Not kidding.

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StillHummer

· #9 · Oct 22, 2020

Tom E-Tron said:
I reserved the Edition 1, E-Tron is the best car I have ever owned by a long shot. Comfortable, bank vault quiet, full of cool features, and fun to drive, very surprising when you put it in "Dynamic" mode and push it on a winding road. Good range, and charges very fast, it was a major upgrade from our Tesla.

I do not think the Hummer will have 500 miles of range, I think the consumption will be 500-550 wh/mi watt hours / per mile, which calculates to 375 to 400 miles of range. Of course on a flat country road at 35-50 MPH 500 miles might be a long shot possibility. The Hummer EV is going to have very high consumption at freeway speeds, and if you drive it over the speed limit on the motorway, you will not go far between charges.

AH, I'm sorry, I misread. I agree.

Tom E-Tron said:
Hi, Wow, you guys reply quick... When GM quoted the 350+ mile range they were referring to where they think the EPA estimate is going to be. On Bolt they quoted 200 miles, and when it came to production was 238 miles EPA, so I expect they are slightly sandbagging. GM is not likely to oversell, and then under deliver. The EPA rating is not everything, and not all EPA ratings are created equal, for example on our E-Tron with a wimpy 204 mile EPA range, we have always been able to beat that even at freeway speed 60-70+ mph on a road trip. On our Tesla we had before the E-Tron had a 270 mile EPA range, but was never able to achieve that on a road trip, we saw 220-230 miles which is right about what we get from our E-Tron.

Lol, yeah, a group of us have been here since January/February...and we tend to reply pretty fast 😆. It's our passion, this Hummer EV.

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