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New 2021 Model S battery cells & packs

Jeff N

Active Member
Oct 31, 2011
2,401
3,244
This is an article I just wrote about charging the new battery pack on V2 Superchargers that includes graphs supplied by @omarsultan.

 
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MP3Mike

Well-Known Member
Feb 1, 2016
15,811
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Oregon
This is an article I just wrote about charging the new battery pack on V2 Superchargers that includes graphs supplied by @omarsultan.

Or if there is a boost converter in the Plaid Model S to up the voltage like Porsche uses in the Taycan. (and the voltage reported is after the boost not directly from the Supercharger.)
 

Jeff N

Active Member
Oct 31, 2011
2,401
3,244
Or if there is a boost converter in the Plaid Model S to up the voltage like Porsche uses in the Taycan. (and the voltage reported is after the boost not directly from the Supercharger.)
Yeah, I should have mentioned that as a possibility but it seems like a significant expense for a modest voltage boost. Not impossible as a transition strategy. It’s a mystery.
 

Jeff N

Active Member
Oct 31, 2011
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@wk057 had tweeted about this issue and that maybe Tesla was using "trickery". The question is that on the Supercharger side or is it on the vehicle side.
Something possibly somewhat analogous happened with the old squat BTC CCS/CHAdeMO DC chargers often installed at early EVgo sites. They were initially running at 100A peak which matched their affixed nameplate specs but some were silently upgraded to 125A later on. Did they get new charger circuit board upgrades or were they latently capable of being pushed harder? I’ve never bothered to find out.
 

wk057

Senior Tinkerer
Feb 23, 2014
5,692
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Hickory, NC, USA
The issue is that the V2 superchargers use a stack of V2 charger modules. These have some components inside that make it pretty unsafe to push 450V through them. Generally with components that have a voltage rating (capacitors, for example) you'll want to stay something like 10% under their spec'd rating as a rule of thumb when utilizing them in a hardware design. In the V2 charger modules there are components with 450V ratings, making the 410V nameplate spec on the charger the spec with the 10% safety margin. In short, 410V is sensible for continuous operation and longevity.

If Tesla intends to replace these V2 units entirely before plaid or other > 410V cars make up a large percentage of the fleet... I'd maybe make that risk trade off if I were on the engineering team making that call. But if they intend to keep this up indefinitely, the V2 units will likely start failing under these conditions eventually.

The trickery I mentioned would be that the supercharger would CC/CV up to 410V, then the car would renegotiate the connection and use the new onboard charger to boost the supercharger's output with the input in normal "AC" charging mode (DC charging contactors open) if the charger were designed to handle this (most chargers can handle DC input). But if it's getting much more than ~30kW above 410V, then this likely isn't the case and they're probably just pushing the hardware in the supercharger hard to get that higher voltage.

Fingers crossed that they plan on replacing the V2 hardware with V3 or better.

Don't get me started on V1... if V1 can charge plaid at 450V then Tesla is insane... those units could barely do 410V safely.

Also, the "urban" variant of charger internals can do about 500V despite spec at 410V.

There's also a potential legal ramification to this, too, as Tesla was getting the V2 superchargers field listed for code compliance based on the data plates they have. It's likely illegal for them to push them out of this certified spec in some jurisdictions. IANAL, but I think anything that "big oil"/TSLAQ can easily use to make Tesla look bad is probably something they shouldn't be doing. Headline: "TESLA FOUND TO BE UNSAFELY PUSHING EQUIPMENT BEYOND LEGAL LIMITS!"
 
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Zoomit

Active Member
Sep 1, 2015
2,220
4,214
SoCal
This is an article I just wrote about charging the new battery pack on V2 Superchargers that includes graphs supplied by @omarsultan.

There’s does seem to be something strange going on here. The @omarsultan V2 Supercharger data indicated 455v at 80% SoC at 0.7C (~70/100kW). A similar example from Model 3 at 0.5C and 80% is 400V. (Ref: Bjorn video @ 6:00)

That would seem to indicate a max voltage for Model S at ~458V, which is of course inconsistent with the OM data of 450V nominal. The equivalent max voltage for a 96s Model 3 pack is ~403V. The Model S pack would need to be 109s to make that work and would have a nominal voltage of 403V [109*3.7]. If the Model S pack is 450V nominal, it should be at about 507V while charging at 0.7C and 80% SOC. Instead, it was almost precisely 10% lower at 455V.
 
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omarsultan

Active Member
Jun 22, 2013
3,602
12,710
Northern California
Here is the voltage for all three SC sessions:

IMG_3EFA72739E90-1.jpegIMG_88C81FBD853F-1.jpegIMG_87680171DE7D-1.jpeg
 

Jeff N

Active Member
Oct 31, 2011
2,401
3,244
There’s does seem to be something strange going on here. The @omarsultan V2 Supercharger data indicated 455v at 80% SoC at 0.7C (~70/100kW). A similar example from Model 3 at 0.5C and 80% is 400V. (Ref: Bjorn video @ 6:00)

That would seem to indicate a max voltage for Model S at ~458V, which is of course inconsistent with the OM data of 450V nominal. The equivalent max voltage for a 96s Model 3 pack is ~403V. The Model S pack would need to be 109s to make that work and would have a nominal voltage of 403V [109*3.7]. If the Model S pack is 450V nominal, it should be at about 507V while charging at 0.7C and 80% SOC. Instead, it was almost precisely 10% lower at 455V.
You’re good! Um, yeah, that’s the topic of my pending follow-up article….
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,020
12,071
San Diego
which is of course inconsistent with the OM data of 450V nominal.
Other than that Owner’s Manual inconsistency issue, do we have any reason to think it isn’t just a 108s pack? (I assume 108s makes more sense since it is divisible by 6…or 4…while 109 is a prime number…I guess the series modules don’t have to have the same number of series cells though so maybe it does not matter that 109 is prime.)

I thought that was the only piece of data we had (prior to Supercharging voltage data) which suggested what the pack configuration was. And there is really no reason Tesla has to be consistent in the Owner’s Manual, is there?

Is there something else that suggests a 500V/120s pack?

They could also reconfigure the pack after charging to make it 120s of course, Porsche does the ~400V to ~800V switch (don’t they?) but that is totally different and easier to do (take half the series 800V stack and put it in parallel with the other half). Tesla going to a great deal of trouble with a ton of pack reconfiguration to go from 455V to 500V, just so the Owner’s Manisl is consistent seems excessive. Unless I am missing some sort of trick here…
 
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Mike4660

Member
Jun 26, 2021
8
6
Florida, USA
Anyone think they'll switch the LR to the 4680 cells in 2022? I'm getting close to an upgrade (I've been driving my 2014 for 7 years now). Would LOVE a 500-mile range LR. Acceleration is fast enough, don't need to spend the extra cash for Plaid+.
How much do you estimate a new battery pack will cost/
 

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