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Interesting write up on the e-tron battery buffer

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Old 02-14-2019, 08:05 AM
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Default Interesting write up on the e-tron battery buffer

From inside EVs:
https://insideevs.com/audi-e-tron-83-of-95-kwh-battery-pack
Old 02-14-2019, 01:01 PM
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Originally Posted by alexlear
InsideEV's are just hunting for clicks, and the author of this article is a clown to say the things he says. Audi is keeping in reserve about 2-3kWh more than Tesla does on their packs, and it seems from Bjorn Nyland's testing this is all on the high end, hence the ability to charge to 100% while still pulling nearly 50kW. I think it is great to have larger reserve, so you do not have to worry about charging to 100% regularly, and running the battery down to near zero, as it is protected. Tesla runs their batteries nearer the edge of danger, hence the massive amount more spontaneous Tesla fires then any other EV I have seen.

Speaking of Bjorn, I saw he is complaining about his 10/10 Model X again, now it seems to have rust growing in several areas, and squeaky steering column, Is that normal on a 2 year old $130K car?

For you Alex, I ran into another Electrify America Charging station off the map today that is under construction, this one is at Alderwood Mall in Lynnwood

Old 02-14-2019, 03:45 PM
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Originally Posted by Tom-ETRON
InsideEV's are just hunting for clicks, and the author of this article is a clown to say the things he says. Audi is keeping in reserve about 2-3kWh more than Tesla does on their packs, and it seems from Bjorn Nyland's testing this is all on the high end, hence the ability to charge to 100% while still pulling nearly 50kW. I think it is great to have larger reserve, so you do not have to worry about charging to 100% regularly, and running the battery down to near zero, as it is protected. Tesla runs their batteries nearer the edge of danger, hence the massive amount more spontaneous Tesla fires then any other EV I have seen.
Poorly written and researched "article", I agree.
  • Spends the first third of the article trying to pin down the usable capacity; 81? 82.5? No, 83.6kWh just like it says on the Audi website.
  • "They are claiming 150-kWh charging power good all the way to 80%." Uh, 150kW not 150kWh.
  • "its drive efficiency may not be as good as the Tesla Model X" followed by "We docked the drive line efficiency from .87 to .85". So automatic .02 off if it's not a Tesla…and he got the drag coefficient wrong.
  • Audi sacrificed usable capacity in order to tout the 150kW to 80% charge rate: The e-tron's charging performance must hurt the Tesla fans waiting for Supercharger Gen III, but this makes no sense. The buffer takes away about 50 miles of critical EPA range potential. Most EV customers are unfamiliar with charge dynamics, but everyone understands 50 miles more range. Even without the additional buffer, the e-tron's charge characteristics are superior, so Audi could tout both.
  • Less efficiency = less range = more cycles, so they need the buffer to increase the longevity of the pack: Huh? Is this even a factor for normal use? Long distances and fast charging are not the norm with most EV's. "This 10% less range also increases battery cycles by 10%". Could someone explain that claim to me.
IMO, Audi decided to deny the customer the ability to critically abuse the battery pack. Even if fast charged repeatedly to 100% the e-tron should be subject to significantly less degradation because of the increased buffer. Sean Mitchell (one of the many YouTube fanboys) has an interesting video on how to ruin your Tesla battery (which he did). I think Audi is being careful, not allowing the end user to inadvertently (or otherwise) damage the battery pack.
Old 02-14-2019, 04:54 PM
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I agree. The buffer is appropriate and sized correctly. It's also likely a split between the energy at the "top" and "bottom" of the cells, above 4.1V and below 3.3V. I think the jury will be out for a while on what effect repeated fast charging (@150kw) will have on pack longevity but that also won't be the expected normal charging usage (most people charge slowly at home). Even at 1.5C charge rate, it's not that high since the heat is handled properly.

Tom-ETRON, thanks for the info on Lynnwood. I'm still hoping for charging sites near Kellogg, ID and Ritzville, WA along I-90. The distance between Missoula-Spokane-Ellensberg sites are too far for comfort. The distance on the map seems possible until you factor in the elevation change. I can probably make it heading West but going East is going to kick in range anxiety. Here's the elevation profile along I-90. The peak at the 300 mile mark (Lookout Pass) is the real problem. I'm sure I will find a workable solution until the network fills in a bit more.



Last edited by alexlear; 02-14-2019 at 07:44 PM.
Old 02-14-2019, 06:38 PM
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Originally Posted by alexlear
Here's the elevation profile along I-90. The peak at the 300 mile mark (Lookout Pass) is the real problem.



What did you use to plot the elevation?
Old 02-14-2019, 06:38 PM
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Originally Posted by alexlear
I agree. The buffer is appropriate and sized correctly. It's also likely a split between the energy at the "top" and "bottom" of the cells, above 4.1V and below 3.3V. I think the jury will be out for a while on what effect repeated fast charging (@150kw) will have on pack longevity but that also won't be the expected normal charging usage (most people charge slowly at home). Even at 1.5C charge rate, it's not that high since the heat is handled properly.

Tom-ETRON, thanks for the info on Lynnwood. I'm still hoping for charging sites near Kellogg, ID and Ritzville, WA along I-90. The distance between Missoula-Spokane-Ellensberg sites are too close for comfort. The distance on the map seems possible until you factor in the elevation change. I can probably make it heading West but going East is going to kick in range anxiety. Here's the elevation profile along I-90. The peak at the 300 mile mark (Lookout Pass) is the real problem. I'm sure I will find a workable solution until the network fills in a bit more.



Kellogg and Ritzville are coming, I assure you, as is Yakima as part of cycle 1. They are hitting western WA hard right now, both stations in Everett started Feb 1, and already have significant progress. One is a 10 stall highway station, and the other is a 3 stall community station that also has level 2 for a 4th stall. I am going to venture to Marysville premium outlet mall this weekend, I think that one is started too. Renton and Redmond are both started although just fencing, and equipment moved in. I am really curious where they are putting the highway station north of Marysville, thinking Mt Vernon or Burlington, but need to keep a watch out.
Old 02-14-2019, 06:48 PM
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Originally Posted by LavaGrau_A3
Poorly written and researched "article", I agree.
  • Spends the first third of the article trying to pin down the usable capacity; 81? 82.5? No, 83.6kWh just like it says on the Audi website.
  • "They are claiming 150-kWh charging power good all the way to 80%." Uh, 150kW not 150kWh.
  • "its drive efficiency may not be as good as the Tesla Model X" followed by "We docked the drive line efficiency from .87 to .85". So automatic .02 off if it's not a Tesla…and he got the drag coefficient wrong.
  • Audi sacrificed usable capacity in order to tout the 150kW to 80% charge rate: The e-tron's charging performance must hurt the Tesla fans waiting for Supercharger Gen III, but this makes no sense. The buffer takes away about 50 miles of critical EPA range potential. Most EV customers are unfamiliar with charge dynamics, but everyone understands 50 miles more range. Even without the additional buffer, the e-tron's charge characteristics are superior, so Audi could tout both.
  • Less efficiency = less range = more cycles, so they need the buffer to increase the longevity of the pack: Huh? Is this even a factor for normal use? Long distances and fast charging are not the norm with most EV's. "This 10% less range also increases battery cycles by 10%". Could someone explain that claim to me.
IMO, Audi decided to deny the customer the ability to critically abuse the battery pack. Even if fast charged repeatedly to 100% the e-tron should be subject to significantly less degradation because of the increased buffer. Sean Mitchell (one of the many YouTube fanboys) has an interesting video on how to ruin your Tesla battery (which he did). I think Audi is being careful, not allowing the end user to inadvertently (or otherwise) damage the battery pack.
I think InsideEV's has really gone off the rails, way too many poorly written pieces with too much misinformation and spin. They are trying so hard to write Tesla puff pieces hoping Elon will re-tweet the links leading to thousands of hits. I used to like their work, but nowadays I feel Mr Tesla (Fred Lambert) is doing a better job with his stories. I now consider insidEV's right down there with Clean Technica for journalistic integrity, their writing barely offers any value for people who know the industry.

BTW, what do you guys think about the GM Rivian Amazon threesome? pretty interesting, I think right up there with Toyota merging in Panasonic's battery operations,
Old 02-14-2019, 07:26 PM
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Originally Posted by perlfather
What did you use to plot the elevation?
Use the Google "My Maps" instructions from here to create a route: GPS Visualizer: Google API Keys

Then copy the share link in to the "Or provide the URL of data on the Web" section of this link: GPS Visualizer profile input form

Then click "Draw the profile" button.
Old 02-14-2019, 07:39 PM
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Originally Posted by Tom-ETRON
BTW, what do you guys think about the GM Rivian Amazon threesome? pretty interesting, I think right up there with Toyota merging in Panasonic's battery operations,
I like what I'm seeing from Rivian. I would genuinely consider a Rivian R1T (I'm sticking with e-tron, though). Being an EV startup is hard and I want them to succeed. Any good partnerships or investments will probably be important, at least in the short term. I'm not sure what their financial situation is but EV startups usually burn through initial investments fast and then go belly up when the realities of the automotive world arrive.
Old 02-14-2019, 07:43 PM
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Originally Posted by Tom-ETRON
Kellogg and Ritzville are coming, I assure you, as is Yakima as part of cycle 1. They are hitting western WA hard right now, both stations in Everett started Feb 1, and already have significant progress. One is a 10 stall highway station, and the other is a 3 stall community station that also has level 2 for a 4th stall. I am going to venture to Marysville premium outlet mall this weekend, I think that one is started too. Renton and Redmond are both started although just fencing, and equipment moved in. I am really curious where they are putting the highway station north of Marysville, thinking Mt Vernon or Burlington, but need to keep a watch out.
That's really exciting, thanks. I'm looking forward to testing out the charging network with the e-tron.


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