Standard Range Plus Supercharging Speed
- Thread starter ab26
- Start date
willow_hiller
Active Member
It's hard to make it out on the screen, but it looks like the outside temperature while charging is in the 50s. That being said, with all these videos maxing out at 102 kw I cannot help but wonder if there's some sort of temperature/beginning SOC independent software limit on the top end.
Will the improved v2 charging and the new v3 charging help the SR+ at all then? I guess the on-route battery heating will help a bit, but apart from that?
V3 Superchargers will help all cars in busy environments by allowing dedicated charging up to the max amperage the car requests. Whether the SR battery will accept more than the 145kW output of a V2 Supercharger is not yet confirmed. ORBW will definitely help either way.
Are you confident that the SR+ will accept even the 145 kW of the v2? And if so - based on what, since many seem to suggest it will not even reach 120 kW?
Does this M3 have the update that would allow the increased charging speed? The LR was capped about 120KW before if I’m not mistaken.
Big Earl
bnkwupt
Hard to tell if it’s a temperature restriction or not. There are not regen dots, but the temp is in the 50s, so it might have been limiting the maximum rate. We really need another video or two to be sure.
Could have been a slow Supercharger, too. I’ve come across that several times.
Could have been a slow Supercharger, too. I’ve come across that several times.
At a very high level, the battery charge rate is limited by three things:
1) ability to apply the desired amperage to the cells
2) ability to dissipate the heat generated due to internal resistance at high amperage
3) ability of the cell chemistry to accept the power without damage
The LR cars can charge at 250kW or more. 256kw has been seen. This means that the wire harness from the charge port to the battery is capable of the amperage to support 250kW for at least a short period of time. It also means the battery cooling system is able to remove and dissipate the thermal energy created by the charging process. (IIRC, Li-ion charging is actually endothermic, but the IR creates the heat.) The capability of the cooling system is defined by parameters such as coolant volume, coolant pump size/flow rate, heat exchanger size/efficiency, contact area on each cell, etc. In order to preserve commonality and simplify assembly, I expect both the charge port wire harness and cooling system components are the same across the Model 3 line. This means they're sized for 250 kW into a ~75 kWh battery.
We know the SR battery has about 2/3rd the number of cells as the LR battery. So if we charge the SR battery at the same C-rate as with the LR battery, it can take 0.67x250= 168 kW. And we have every reason to believe the SR cells themselves are the same as LR cells...same chemistry and C-rate capability. So the SR battery can take ~168 kW at the same level of stress as the LR battery can take 250 kW.
Additionally, if the charging harness and cooling systems are common, they are sized to handle 250kW, so the SR cars have excess capability for SR battery charging at 168 kW. If anything, I expect the SR battery to charge at a higher c-rate than the LR. This would be made possible by using this excess cooling system capability.
In summary, I expect the SR to exceed 145 kW charging. It's likely to be at least 165 kW, if not higher, depending on exactly how many cells Tesla included in the SR battery relative to the LR battery.
Last edited:
Ajlepore
Member
How much range do you expect a SR+ to get going 70/75/80 mph?
Ajlepore
Member
Thank you for the informative answer Zoomit. I think I understand. That is also why the different models charges roughly the same percentage of battery in the same time I guess?
But your model suggests that the sr+ will be able to charge at 145 kW at the v2 as the LR. Therefore also charging roughly 65% in 20 min whereas LR charges 55%. That sounds promising but I am not sure why it is supposed to be possible? Wouldn’t that put more stress on the sr+ cells?
But your model suggests that the sr+ will be able to charge at 145 kW at the v2 as the LR. Therefore also charging roughly 65% in 20 min whereas LR charges 55%. That sounds promising but I am not sure why it is supposed to be possible? Wouldn’t that put more stress on the sr+ cells?
Legen---dary
Member
Drove (SR+) pretty hard for an hour or so, around 140km/h. Got it down to 19%. Plugged into supercharger and max was briefly 102kW.
Ambient temp was around 15 Celsius.
Charge went pretty much the same as that vid.
That charger... charges 50c/min over 60kW, and 25c/min under. A 72kW urban charger is 44c/22c.
Without the battery conditioning yet, I've found it difficult to predict the charge rate such that it starts just under 60kW for maximum savings.
Ambient temp was around 15 Celsius.
Charge went pretty much the same as that vid.
That charger... charges 50c/min over 60kW, and 25c/min under. A 72kW urban charger is 44c/22c.
Without the battery conditioning yet, I've found it difficult to predict the charge rate such that it starts just under 60kW for maximum savings.
Yes, SR charging at 145kW is ~50% higher c-rate than LR charging at 145kW. Therefore more amps into each cell, more heat output on a per cell basis, and more "stress". Also SR would have more restrictive battery temperature requirements to charge at that rate.
With more corroborating reports like this, it's certainly seems that the current SR charge profile is limited to 102 kW.
Thanks for the answer.
I guess 102 kW would already be more than 67% percent of the 120 kW (85% actually).
But, following your line of thought, why would SR+ be capped at 102 kW now and not just accepting 120 kW?
And why dont you think that it will just keep the current percentage and charge at 85% of the 145 kW on the v2?
Are there no reports from any SR+ owners with the v2 update yet? Has it not been widely rolled out yet?
I don't know why it's only 102kW now, so I'm not sure if it would keep the same 85% of 145kW with an updated charging profile. But probably not as 145kW is stall limitation not a car limit.
I only saw reports of 145kW charging on 2019.7.11, and those were LR cars. Those folks were subsequently updated to higher revs and lost the increased charge profile.
M3BlueGeorgia
Active Member
Yep, you'll be charging on a warm battery so you should see maximum charge level.
But to get full benefit, be careful not to share your Supercharger pair, for example if someone is already on 3A, avoid 3B.
Not always possible on a busy Supercharger station, and the trick there is to try to figure out whose been charging longest, and share the A/B with them.
Similar threads
