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Discussion Starter · #1 · (Edited by Moderator)

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So if we extrapolate the math the EV2 will probably weigh at most 7,500 pounds.

Also interesting factoid: 212.7 kWh of usable energy

The total size of the battery according to C&D is closer to 250 kWh, 86% usable. (Numbers sound close to my Volt's percentage of usable vs non-usable)
Edit: Seems to large though????

BTW Welcome to the forums.
 

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Discussion Starter · #3 ·
So if we extrapolate the math the EV2 will probably weigh at most 7,500 pounds.

Also interesting factoid: 212.7 kWh of usable energy

The total size of the battery according to C&D is closer to 250 kWh, 86% usable. (Numbers sound close to my Volt's usable vs non-usable)

BTW Welcome to the forums.
That EV2 will be close to the Rivian in weight! Interesting.

Super curious to see how battery weight will start shifting down as we continue developing more and more energy dense batteries.

250 kWh... That is just massive!

Thanks!! Happy to be here. Very excited for the EV3X that I'll be getting... eventually!
 

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C&D likely miscalculated the pack's gross capacity. The EPA amp-hour rating makes sense as all along, we had been assuming at least 100 A-h/cell. Tim Grewe has referenced that value several times. The architecture is (2) 96S3P subpacks in-parallel, which at 100 Ah/cell would calc out at about 588 A-h at 96S6P configuration. It is likely Ultium Cells has since slightly upgraded cell capacity since then to about 107 Ah. But the actual "average" voltage/cell for NMC/NMCA chemistries used to calc the total w-h capacity is about 3.65-3.7 VDC. The typical NMC cell voltage only gets to 4.2 VDC at 100% SOC. That means the pack voltage for gross kWh capacity would be 96x3.7 = 355 VDC. 355 x 617 = 219 kWh. We're looking closer to 95-96% usable capacity, which matches closer with what we're seeing from the latest Tesla (Plaid NCA chemistry) and Hyundai (Ioniq 5 NMC chemistry) packs.

There is absolutely no way GM would be using a 14% buffer similar to the old Volt buffer. The Volt needed that buffer to ensure 100% power rating at both "full" and "zero" usable charge. PHEV packs.
 

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C&D likely miscalculated the pack's gross capacity. The EPA amp-hour rating makes sense as all along, we had been assuming at least 100 A-h/cell. Tim Grewe has referenced that value several times. The architecture is (2) 96S3P subpacks in-parallel, which at 100 Ah/cell would calc out at about 588 A-h at 96S6P configuration. It is likely Ultium Cells has since slightly upgraded cell capacity since then to about 107 Ah. But the actual "average" voltage/cell for NMC/NMCA chemistries used to calc the total w-h capacity is about 3.65-3.7 VDC. The typical NMC cell voltage only gets to 4.2 VDC at 100% SOC. That means the pack voltage for gross kWh capacity would be 96x3.7 = 355 VDC. 355 x 617 = 219 kWh. We're looking closer to 95-96% usable capacity, which matches closer with what we're seeing from the latest Tesla (Plaid NCA chemistry) and Hyundai (Ioniq 5 NMC chemistry) packs.

There is absolutely no way GM would be using a 14% buffer similar to the old Volt buffer. The Volt needed that buffer to ensure 100% power rating at both "full" and "zero" usable charge. PHEV packs.
Yeah this sounds more in line with everything!
 

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Just under 3,000 LBS for the battery is quite a lot but at least it gets enough estimated range.
The Hummer pack (and likely the Silverado packs) will likely be a lot heavier per kWh than what most of the other Ultium-based EV packs for other upcoming GM EV's. (Lyriq, Equinox, etc.). Since the BT1 platform does not use a conventional frame-and-rail structural concept, but an "integrated body-frame-pack" structural concept, the BT1-based Ultium pack structure itself has to be extremely strong. It is the key element to provide extreme torsional stiffness to keep everything together while towing, bouldering, etc. This means the outer frame and crossmembers carrying the modules will be super-strong and have rigid attachments, and likely be heavier than required for BEV3-platform passenger EVs. Also, transmitting almost 2,000 total amps to those three 259-kW motors means massive bus-bars, main contactors, etc, also adding weight. That said, the modules themselves will likely be very similar or identical to Lyriq's . And for recycling, the unique issue is recycling the cells within the modules. Everything else - bus-bars, module cases, pack frames, etc. are either stamped steel or aluminum and recyclable through conventional means.
 

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haha they pulled a Ford!!
haha they pulled a Ford!!
I would not put much stock in any of this, When tom does a 70 mph range test and charging tests we will have real data, until then this is nothing more than speculation.

Also when calculating battery size, you use amp hours and nominal voltage, not max voltage.
 

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I would not put much stock in any of this, When tom does a 70 mph range test and charging tests we will have real data, until then this is nothing more than speculation.

Also when calculating battery size, you use amp hours and nominal voltage, not max voltage.
I seem to remember the nominal voltage coming up for some when discussing the battery pack size for the Lucid. So what does that make the Hummer size pack? Is Car and Driver correct?
 

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I seem to remember the nominal voltage coming up for some when discussing the battery pack size for the Lucid. So what does that make the Hummer size pack? Is Car and Driver correct?
Nominal voltage should be 360V, so 222kWh. Which makes the 212kWh usable a reasonable number, a 5% buffer.
 

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Since the Hummers weight over 8500 pounds they won't have to display the MPGe on the window sticker.

 

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Since the Hummers weight over 8500 pounds they won't have to display the MPGe on the window sticker.

Hmm according to that it seems the Hummer EV payload is actually 1,487, not the originally quoted 1300.
 
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