ALL CyberTruck discussion

[uscbucsfan]

Why? It was well known it would lie on top of the 250kW curve above ~25% SOC. Frequently discussed and widely acknowledged.

Just the way things work. The only limitation was the pack above ~25%.

If Tesla is holding back, it is going to affect both curves if/when they do any unlock, and until a significant portion of the curve can be above 250kW, the higher power chargers won’t help very much. Don’t hold your breath though.

Just that Tesla stated that on a 800v system it can do 15-85% in 18 min. I didn't think they was theoretical in the future.

 

[AlanSubie4Life]

I didn't think they was theoretical in the future.

I assumed it was. This looks like 40-45 minutes 15%-85% unless I screwed up my interpretation?

Anyway the fact they said that does provide some hope, but I definitely would not bank on it. Depends on them getting signoff for those rates.

In any case, we already knew it could not happen on a 800V system with current software based on the prior data. It was just impossible.

 

[MP3Mike]

Also shows the 400V wasn't a big impact (as expected).

If your 400v charger supports really high current, ~700A, like the V3 Superchargers. 400v will be negatively impacted on most, if not all, CCS chargers. (Most limited to ~200A, some up to 500A.)

 

[MP3Mike]

I assumed it was. This looks like 40-45 minutes 15%-85% unless I screwed up my interpretation?

0-15% looks to be ~4 minutes, 15-85% looks to be ~40 minutes.

It would be interesting to see a real 15-85% test. (Where it hasn't just charged the 0-15% portion to see if it is the heat load from charging that slows it down.)

 

[mongo]

If your 400v charger supports really high current, ~700A, like the V3 Superchargers. 400v will be negatively impacted on most, if not all, CCS chargers. (Most limited to ~200A, some up to 500A.)

Of course if it can't handle the current required, there will be an impact.
The point of debate was pack performance and whether the parallel pack setting was limiting charge current (power).

 

[BioSehnsucht]

With this single data point, it's possible that it's the 3rd party's charging system that ran into thermal limits, too.

We'd need to see a different result from some other 800v vehicle on the same system (and in similar weather), to be sure which was the limit.

 

[AlanSubie4Life]

With this single data point, it's possible that it's the 3rd party's charging system that ran into thermal limits, too.

We'd need to see a different result from some other 800v vehicle on the same system (and in similar weather), to be sure which was the limit.

It’s not the first we have seen. This looks exactly the same (after converting the axes):

First charge curve data I've seen.

(E.g. plateau from 65% to 85% at 80kW or whatever)

 

[MP3Mike]

With this single data point, it's possible that it's the 3rd party's charging system that ran into thermal limits, too.

I highly doubt that the Nxu charger ran into any thermal limits. It is designed for continuous 700+kW usage. (There are just no vehicles available to test that.)

Also, I don't think their system had any issues charging a Hummer EV at 350+kW.

 

[Daniel in SD]

Plot of power vs. SoC

https://twitter.com/x/status/1765159704731521500

Really need to arrive at low charge for cybertruck. I wonder why it’s able to charge at full rate at 0% while other Teslas ramp up between 0 and 10%.

 

[MP3Mike]

Really need to arrive at low charge for cybertruck. I wonder why it’s able to charge at full rate at 0% while other Teslas ramp up between 0 and 10%.

We don't know that. Show me the curve for when you arrive at 15% and start charging... It could be significantly different than the 15%+ section of that curve.

 

[AlanSubie4Life]

We don't know that. Show me the curve for when you arrive at 15% and start charging... It could be significantly different than the 15%+ section of that curve.

Why would it be different? What is the theory?

 

[AlanSubie4Life]

0% while other Teslas ramp up between 0 and 10%.

Isn’t this because the chargers are current limited at very low SOC? So voltage is ramping at constant current? Or does that not fit? Asking; I am not sure my statement is correct…

Projecting to a 800v charge configuration, and assuming this same MY 4680 curve, the CT would take 350kW only up to about 10% SOC, which is very low. I would expect (hope!) they can release a more robust charging curve to better use the capabilities of the V4 stations.

Some people know their stuff…
(I do not!!! - can’t keep track of all the voltage and current limiting, )

 

[MP3Mike]

Why would it be different? What is the theory?

Heat buildup in something may be part of the rain for the steps down. If you start with the battery at 15% just preconditioned it might charge faster than it does after it has been charging at 327kW for a while.

 

[AlanSubie4Life]

Heat buildup in something may be part of the rain for the steps down. If you start with the battery at 15% just preconditioned it might charge faster than it does after it has been charging at 327kW for a while.

If that were true, we would have seen some evidence of it before in someone’s 250kW curve, wouldn’t we? Not everyone has started below 20% for those curves.

I am kind of BSing since I have not overlaid the curves, but aren’t they the same? (@Zoomit extrapolation looked dead on so seems like they must be?)

This just looks like a solid software limit. Who knows if they will ever qualify a different curve for these cells.

 

[mongo]

With this single data point, it's possible that it's the 3rd party's charging system that ran into thermal limits, too.

We'd need to see a different result from some other 800v vehicle on the same system (and in similar weather), to be sure which was the limit.

Nope.
It's hard to see, but the line for current is actually two lines, targetCurrent in blue requested by vehicle and actual current in green. They overlap so there was no throttling on the EVSE side of things.

 

[AlanSubie4Life]

Isn’t this because the chargers are current limited at very low SOC? So voltage is ramping at constant current? Or does that not fit? Asking; I am not sure my statement is correct…

This can't be quite right because the Supercharging clearly underperforms even the current limit at very low SOC, as far as I can tell (ramp is steeper than cell voltage increase between "0%" and ~5%). Maybe there are other sensitivities with low voltage cells that require care; I spent some time looking for posts from the regular suspects/experts on Supercharging to explain it but no idea.

Anyway maybe if we knew all the reasons for the 0%-5% or 8% or whatever ramp then it would be more clear why Cybertruck doesn't have that issue. I am sure @Zoomit could explain.

 

[Buckminster]

https://twitter.com/x/status/1765203079840878749

 

[CyberShy]

0-15% looks to be ~4 minutes, 15-85% looks to be ~40 minutes.

It would be interesting to see a real 15-85% test. (Where it hasn't just charged the 0-15% portion to see if it is the heat load from charging that slows it down.)

To me, the only thing that matters is the TIME to reach 80% from low charge. Get it down to 20m or less and I’m happy because then I can leave. I only have a 2-3 hour bladder so the miles or kwhr charged is not important. After 20m, I’m ready to go unless it’s also a lunch stop.

I wonder why it’s able to charge at full rate at 0% while other Teslas ramp up between 0 and 10%.

It doesn’t. At 0%, power ramps up to peak, just quickly. It’s just omitted from this graph (see previous graphs). There might be a larger bottom buffer of capacity.

Isn’t this because the chargers are current limited at very low SOC? So voltage is ramping at constant current? Or does that not fit? Asking; I am not sure my statement is correct…


Some people know their stuff…
(I do not!!! - can’t keep track of all the voltage and current limiting, )

Not sure what you mean. The vehicle requests the current and the chargers provide it. They don’t request voltage, but one leads to the other. V=I*R. Since the battery voltage increases with charge, the BMS manages the current request to the DCFC EVSE/charger.

I might be wrong, too. But we’re all learning this stuff.

 

[AlanSubie4Life]

The vehicle requests the current and the chargers provide it.

As I said it is not (probably) the actual issue only issue here…the charger may not be able to provide the requested current!

But the idea: there are limits to how much current a charger can provide. If the pack voltage is too low at that point, then it won’t be able to hit peak power as a result.

You see this with Teslas on 350kW CCS chargers, for example. They end up providing lower charge rate than a Supercharger at the same SOC and same pack conditions because the charger current maxes out.

It doesn’t. At 0%, power ramps up to peak, just quickly. It’s just omitted from this graph (see previous graphs).

It is qualitatively different than other Tesla vehicles. Check out charge curve limitations up to 5-7% SOC (indicated, not actual).

There’s a 4.5% buffer below 0% for Cybertruck, as there is for other Teslas. Saw this in range tests as I recall.

 

[mongo]

As I said it is not (probably) the actual issue only issue here…the charger may not be able to provide the requested current!

In the 3rd party 800V charger test, it could and it did provide the current requested.

It's hard to see, but the line for current is actually two lines, targetCurrent in blue requested by vehicle and actual current in green. They overlap so there was no throttling on the EVSE side of things.