Battery Progress

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How accurate do you find the range gauges to be? I know there are variables but generally speaking if it says you have 20 miles to 0 would you say that's right...or is it off by 25% (5 miles or so) when you get closer to empty? This always seems to be the case with ICE...or maybe that's just my panic perception kicking in. I have yet to run out of gas in my life (currently knocking on all wood desks within reach).
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I probably missed the discussions about powering a house from a CT if here are any.
It would be interesting to read after the power outages in Ontario.
 

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At least Cleantechnica didn't just lift the quote into the article, but my critique stands.
cleantechnica said:
“As we began the test, it started running beautifully — something we did not expect. In fact, we tested it over and over again — more than 100 times — to ensure we were really seeing what we thought we were seeing,” Kalra said. “The sulfur cathode, which we suspected would cause the reaction to grind to a halt, actually performed amazingly well and it did so again and again without causing shuttling.”
Not as bad as the phrasing chosen in the first article, but still not great.

Red flags everywhere.

-Crissa
 

Crissa

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How accurate do you find the range gauges to be? I know there are variables but generally speaking if it says you have 20 miles to 0 would you say that's right...or is it off by 25% (5 miles or so) when you get closer to empty? This always seems to be the case with ICE...or maybe that's just my panic perception kicking in. I have yet to run out of gas in my life (currently knocking on all wood desks within reach).
Tesla keeps adding in things like route speeds, elevation changes, and now they've added wind.

It's supposedly pretty good.

My Zero's range estimate is... uhh... I don't even keep it on the display. Of course, I live in the mountains.

-Crissa
 
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ajdelange

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How accurate do you find the range gauges to be? I know there are variables but generally speaking if it says you have 20 miles to 0 would you say that's right...or is it off by 25% (5 miles or so) when you get closer to empty?
It's terrible as you might expect understanding what it is. It is the car's estimate of what is left in the battery relative to the 0 mark divided by the rated consumption. How accurate it is depends on haw closely you match rated consumption in the future and actual consumption can vary quite a bit from rated consumption if, for example, one drives fast or into a head wind. I used to see lots of posts talking about what crappy cars Teslas were. These usually involved something like a guy out in the desert on a 95° day driving at 85 mph up hill and into a headwind with 30 miles to go to the next SC confident he'd make it because his gauge showed 40 miles estimated range. After 20 miles the car would run out and stop.

The problem is, of course, that the 40 miles estimated range was calculated under the assumption of, e.g. 300 Wh/mi (so that there were 40*.3 = 12 kWh left in the battery) but with the hill, the wind, the upgrade and the cooling load he was actually pulling twice that (600) and should expect to run out after 12/.6 = 20 miles. Thus using miles range estimates as a measure of battery status is to be deprecated and the smart money set their battery meters to read in %.

Tesla has a much better tool, however. I just described it in what I thought was this thread but I don't see it here so I'll briefly describe it again. You set this up when you depart. You tell the nav system where you are going and it plots out the course but it also looks up speed limits and elevation changes and using those with the rated rate and battery SoC at departure makes a graph of estimated SoC vs miles along the route. In our example The right hand of the line would show a positive SoC at the destination SC. But as the drive progresses the algorithm blends out the rated SoC and blends in the actual historical consumption. As our hypothetical driver encounters the adverse conditions the future part of the curve dips downward and turns first yellow and then red and the intercept falls below 0. This warns the guy that he is not going to make it and he'd better do something about it (which is slow down as there isn't much he can do about the hill or the wind).

I have found this algorithm to be quite accurate. The first estimates of destination SoC can be off by quite a bit (becuase they are based or rated consumption) but once it has enough info to be able to estimate your actual driving on that trip it becomes pretty good usually predicting destination SoC to within a couple of percent.
 


zentico

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The research done at Drexel University seems very similar to work announced in the last few months by two start-ups: Theion (https://theion.de) and Lyten (https://lyten.com).

All claim to have solved the reversibility problem of the cathode in lithium-sulfur batteries, which paves the wave for super-cheap, long-lasting and energy dense batteries. The 2 startups claim that in a year or so such batteries may become commercially available, and Drexel has already filed several patents.

Drexel's key, accidental discovery is a cathode made of a stable low temperature version of "monoclinic gamma-phase sulfur" in a carbon nanofiber matrix that prevents the formation of polysulfides in the electrolyte. Theion's "Crystal Battery" is a patented production process that combines "sulfur’s crystal material properties" with carbon nanotubes and a proprietary solid electrolyte. Lyten relies on "3D Graphene" that achieves "Sulfur-Caging".

Having 3 such announcements makes it believable that at least one of them is not overly optimistic. Maybe by the time our Cybertrucks roll out of Giga Texas, they'll sport lithium-sulfur batteries instead of lithium-NMC, in the process making the price of $39,900 achievable again!
 

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Having 3 such announcements makes it believable that at least one of them is not overly optimistic. Maybe by the time our Cybertrucks roll out of Giga Texas, they'll sport lithium-sulfur batteries instead of lithium-NMC, in the process making the price of $39,900 achievable again!
It takes years to test out new chemistries, and such a different chemistry that would require different manufacturing techniques, I would NOT expect it to be in production vehicles for another5+ years, so 2027-ish... assuming the process to manufacture is actually the same or cheaper than their current processes.

Chemistry is not as fast to implement as is software code. Think about how long Tesla has been working on 4680 and the dry electrolyte... And still not a full production yet, still ramping up.
 

ajdelange

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Leaving the pack at 0% (why was anyone saying 0v?) runs the risk of the batteries being damaged as they sit.
Very important that people understand that leaving a battery at 0% may not damage it at all (e.g 0% set for 3.0V) whereas letting it sit at 0 V will most probably destroy it.
 

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Very important that people understand that leaving a battery at 0% may not damage it at all (e.g 0% set for 3.0V) whereas letting it sit at 0 V will most probably destroy it.
Lithium-based batteries have a very low self-discharge, but it's not zero. A pack at very low SoC will slowly drop, so it's best to avoid such a condition.

Also, the LV battery will not be charged by a depleted HV pack, so eventually you will need to jump-start the car just to charge or open the door.
 


ajdelange

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Apparently someone misinterpreted my post as saying it’s OK to leave a battery at 0%. It doesn’t say that at all. It is my policy to stay out of the bottom 20% if possible.
 

ldjessee

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Apparently someone misinterpreted my post as saying it’s OK to leave a battery at 0%. It doesn’t say that at all. It is my policy to stay out of the bottom 20% if possible.
It doesn't say that, but many people, not reading carefully and paying close attention, could walk away with that.

Average reading comprehension is probably higher here, but still not that high... and sometimes I read these forums late at night when my reading comprehension is not at its best.
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