Updated Model 3 Charging Profiles & Durations

[Zoomit]

I started building EV charging models a number of years ago and with the recent V3 Supercharger announcement finally felt compelled to update my Model 3 models. The results are included below. These are PRELIMINARY ESTIMATES based on the charging data seen at the V3 Beta demonstration on March 6th. I made a number of significant assumptions:

• The baseline V3 charge profile is based solely on this data from reddit user privaterbok.
• The usable battery capacities are 75, 62, 55, 50 kWh (LR, MR, SR+, SR respectively).
• The SR battery is a 92% software-locked version of the SR+ battery. The 8% buffer is all at the top of the battery. There is uncertainty about the SR battery configuration due to ambiguous comments made during the Model 3 announcement. It may actually have fewer cells than the SR+ and not be software-locked, in which case the SR results included here would be invalid.
• The V2 Superchargers are upgraded to allow 145 kW charging, increased from 120 kW today.
• The 145 kW V2 charging profiles assume they are power limited at 145 kW, not current limited at low SOC. It's possible that the power output will ramp up to a peak of 145 kW instead of the steady 145 kW output I modeled. If that is the case, the V2 results included here would overstate the actual capability.
• The charge profiles assume optimal charging conditions. This is more likely now if On-Route Battery Warmup is enabled to alleviate cold battery constraints. This also assumes the V2 Supercharger is used without sharing power.

Due to the four battery configurations and three types of Superchargers, the results have many permutations. So I made a lot of charts and grouped them in the following images:

Charging profiles based on battery configuration (Power vs Battery Level)


Charging duration based on battery configuration (Battery Level over Time)


Range gained over time based on Supercharger type (Rated Range over Time)


Charging profiles based on Supercharger type (Power vs Rated Range)


Finally, here's a bar graph that shows how many rated miles are gained when a 20 minute session is initiated at 15% battery level.

Initial thoughts:

• Much of the increased power from V3 is only accessible if the battery level is below 18%. This is where the 250kW and 1000 mphc specs are reported. During typical driving, most people don't plan to go that low; hence the actual benefits of the 250 kW V3 Supercharger are minor when compared to a V2 Supercharger upgraded to 145kW that is not being shared.
• Getting 75 rated miles in 5 minutes is only possible when starting the charge at a very low battery level (less than about 6%). This is also only possible in the LR RWD.
• There's very little to be gained by MR, SR+ and SR cars using V3, and then it's only possible when the battery level is below 20-30%. (Again, this ignores competing for V2 power sharing.)
• I believe the performance claims in the Tesla blog post. Those claims rely on fleet performance that, in addition to the V3 hardware, include the benefits from 1) On-Route Battery Warmup, 2) the software update to the V2 infrastructure and 3) the revision of Model 3 charging profiles to be more aggressive.

Comments and feedback welcome. Look for updated results down-thread as we get more information about the new Supercharger capability and the SR/SR+ batteries.

P.S. Please don't republish these results without my permission. They are preliminary and need to be validated by more real-world charging experience.

 

[Zoomit]

Here're the plots without thumbnails (if that helps).

 

[Zoomit]

Full res from imgur:
https://i.imgur.com/9CswheD.png
https://i.imgur.com/beYKM1W.png
https://i.imgur.com/mgh5kuo.png
https://i.imgur.com/hH4payw.png

 

[AlanSubie4Life]

Looks like you're in the camp that believes that the taper will be matched on all of the Superchargers, and there are no hardware limitations on V2 and original Supercharger that would prevent that. Were there any V2 superchargers in use at the event with associated video, so you could confirm this assumption? I thought I saw one video from the event that looked pretty slow which looked like it could have been from a V2 supercharger being used with the new 2019.7.11 firmware? But it wasn't at a SoC which would allow us to say one way or another...

Personally I don't see why the tapers wouldn't match, and while I haven't seen anything from Tesla specifically saying that the taper on the V2s will be improved to the maximum allowed by the vehicle, I assume it will... They're trying to get the most throughput possible and I'm not aware of a technical reason.

Any firm data which would confirm this? I guess we will all find out soon enough in any case.

 

[Zoomit]

I do expect the updated charge profiles to carry over to V2 units but don’t know how those units will hold up near 145kW continuous. The units may overheat quickly, in the cables for example, and limit high power into the car. The actual chargers do typically put out 145kW routinely when shared so those aren’t likely a limitation.

We’ll need to see how a 2019.7.11 car charges on an updated V2 unit to know for sure.

 

[THX723]

I would expect 145kW v2 to taper off earlier than v3 in the later phase, due to the non-liquid cooled SC-to-Car cable.

 

[Zoomit]

I’m not sure that’ll be a limitation. Non-Tesla DCFCs operate up to 150kW without liquid cooling.

Of course it really depends on the Tesla cable specs plus how much the charger has been running, ambient temps, etc.

The V3 units should be more robust to varying conditions, as long as the cooling mechanicals can keep up.

 

[MP3Mike]

Of course it really depends on the Tesla cable specs plus how much the charger has been running, ambient temps, etc.

From: V3 Supercharger Revealed 250kW

What's even more interesting to me, is the spec limits on the monolith cables at each stall:
Rated Voltage: 410 VDC
Rated Current: 210 A Continuous
Rated Current: 270 A @ 67% (T_=20 min)

This equates to only 86kW Continuous, or 111kW with a duty cycle of 67% (T_=20min).

So the car and/or site has to keep track of usage on the cable to stay in spec.

 

[AlanSubie4Life]

From: V3 Supercharger Revealed 250kW



So the car and/or site has to keep track of usage on the cable to stay in spec.

Hmm. Maybe they'll replace the cables with higher spec ones on the busier stations? Might be a bit too heavy then, who knows. Or they won't replace them, and things won't be as good as they say in reality (that's kind of what I expect...but they are talking about improving throughput on their existing stations with the updates and I would have thought that cable heating would have played into their calculations).

Seems unfortunate to be limited by the cable.

 

[THX723]

Hmm. Maybe they'll replace the cables with higher spec ones on the busier stations? Might be a bit too heavy then, who knows. Or they won't replace them, and things won't be as good as they say in reality (that's kind of what I expect...but they are talking about improving throughput on their existing stations with the updates and I would have thought that cable heating would have played into their calculations).

Seems unfortunate to be limited by the cable.

That's the reality. When Tesla say xxx-kW charging, they sight peak rate even if for just a moment. Musk's twitt seem to suggest software update only -- no hardware replacement (e.g. new cable).

 

[Zoomit]

That cable spec is curious. I thought the Model 3 was getting well over 300A, which by itself would exceed the spec leaving no room for higher power charging. I do suspect that my V2 estimates are the most likely to change when real data hits the interwebs.

Just another day in the life of an amateur EE trying to sleuth out how are cars work.

 

[MP3Mike]

That cable spec is curious. I thought the Model 3 was getting well over 300A, which by itself would exceed the spec leaving no room for higher power charging. I do suspect that my V2 estimates are the most likely to change when real data hits the interwebs.

Just another day in the life of an amateur EE trying to sleuth out how are cars work.

That spec is for the V2 cables. V3 cables are liquid cooled and likely have much higher specs. (The Model 3 will be pulling ~700A at the 250kw peak.)

 

[Zoomit]

Right, I was questioning how the current V2 infrastructure can apparently be upgraded via software to support 145kW output to one stall. If they have to swap out all the V2 cables, that’d take awhile.

 

[GigaGrunt]

SR and SR+ are same pack. 3 packs for M3 (SR/SR+, MR, LR), each will have its own 1PH or 3PH variant for international.

 

[Zoomit]

SR and SR+ are same pack. 3 packs for M3 (SR/SR+, MR, LR), each will have its own 1PH or 3PH variant for international.

I suspect this as well, but haven’t seen any definitive proof. Have you?

 

[George S. Bower]

Here're the plots without thumbnails (if that helps).

]

Hey zoomit,
do you have the predicted charger voltage and amperage that goes along with these plots??
I'm mostly just interested in the M3LR RWD.

 

[Zoomit]

Hey zoomit,
do you have the predicted charger voltage and amperage that goes along with these plots??
I'm mostly just interested in the M3LR RWD.

No. I was originally thinking the peak amperage might be ~750A using some simplistic assumptions, but it's probably lower, around 620A, based on a reddit conversation. I'd appreciate any additional insight on this.

 

[George S. Bower]

No. I was originally thinking the peak amperage might be ~750A using some simplistic assumptions, but it's probably lower, around 620A, based on a reddit conversation. I'd appreciate any additional insight on this.

Thx for answering.
my latest thinking is that at lower SOC's we could see 632 amps and 393V= 248 kw

Ingineer discovered that the cable between the charge port and the battery was a 3-0 cable and was bigger than model S. It's in one of his videos. He claimed to have the mfg's specs on that cable and said it was good for 430 amps but I'm not sure if that's a continuous rating or not. Most conventional copper 3-0 cable are only good for low 300 amp range so 430 seemed pretty racey at the time.

Now we have people saying that tesla could be pushing anywhere from low 600 to 700 amps thru that cable.

What do you think about that??

edit changed "bigger than model 3" to:
"bigger than model S"

 

[MarcG]

Any thoughts on potential voltage changes to the pack that would lower the current needed to achieve 250kW+?
For example, at 700V you would “only” need 357A, which would be within cable specs.
That might necessitate a re-wiring of the pack though, which I’m not sure can be done on the fly for he entire M3 fleet..

 

[GigaGrunt]

I suspect this as well, but haven’t seen any definitive proof. Have you?

Part number stickers, actual packs