320kW Charging?

Bobby Garrity

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#1
Some simple math reveals that the new Roadster should be capable of charging at at least 320kW. Let's take a look:

-The Long Range Model 3, with a 75kWh battery, can achieve a peak charging rate of 120kW on a Supercharger
-The base model new Roadster has a 200kWh battery
-(120kW/75kWh) * 200kWh = 320kW

So this means that even if there are no battery improvements at all compared to the current Model 3, the new Roadster should a reach peak charging rate of 320kW assuming no other bottlenecks and a fast enough charger.

In a previous earnings call, Tesla seemed to shoot down the idea of 300kW+ chargers, claiming there was a trade-off between charging speed and long-term battery health. They had contradicted an earlier Tweet from Elon referring to 350kW as a "child's toy", and those comments are even more confusing when you consider that they have already announced a product theoretically capable of charging at 320kW with current technology and no trade-offs.

So what's going on? Was Tesla trying to downplay Supercharger V3 with that earnings call so we get more excited when they announce it? Or do they actually plan V3 to be slower than 350kW, with the rational that 250kW or so is fast enough even if the Roadster can easily take more?

P. S. Using 80kWh for the Model 3 gives you a rate of 300kW the Roadster. Points still stand.
 

PNWmisty

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#2
Some simple math reveals that the new Roadster should be capable of charging at at least 320kW. Let's take a look:

-The Long Range Model 3, with a 75kWh battery, can achieve a peak charging rate of 120kW on a Supercharger
-The base model new Roadster has a 200kWh battery
-(120kW/75kWh) * 200kWh = 320kW

So this means that even if there are no battery improvements at all compared to the current Model 3, the new Roadster should a reach peak charging rate of 320kW assuming no other bottlenecks and a fast enough charger.

In a previous earnings call, Tesla seemed to shoot down the idea of 300kW+ chargers, claiming there was a trade-off between charging speed and long-term battery health. They had contradicted an earlier Tweet from Elon referring to 350kW as a "child's toy", and those comments are even more confusing when you consider that they have already announced a product theoretically capable of charging at 320kW with current technology and no trade-offs.

So what's going on? Was Tesla trying to downplay Supercharger V3 with that earnings call so we get more excited when they announce it? Or do they actually plan V3 to be slower than 350kW, with the rational that 250kW or so is fast enough even if the Roadster can easily take more?

P. S. Using 80kWh for the Model 3 gives you a rate of 300kW the Roadster. Points still stand.
Maybe it's a limitation of the size/design of the charge connector plug.
 

Bobby Garrity

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#3
Maybe it's a limitation of the size/design of the charge connector plug.
That's something I've wondered for a long time but have never found an answer to. Not just with Tesla's connector, but with connectors in general. Does anyone here know anything about charging speed and the connector size?
 

TrevP

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#4
We do know the charge port connector on the Semi truck is considebly larger. At this time they’re using adapters to hook up to the existing Superchargers while they drive it around the US

This charge port is designed to handle megawatt level charging.

Personally I think the Roadster will continue to use the same charge port as all current Teslas
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Ryan

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#5
The thought has occurred to me: could the Roadster hook up to the Megachargers? Technically I imagine it's "yes" but in practice probably not, as trucking companies probably wouldn't want their drivers held up by even a few minutes by the occasional random supercar cruising through.
 

TrevP

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#6
The thought has occurred to me: could the Roadster hook up to the Megachargers? Technically I imagine it's "yes" but in practice probably not, as trucking companies probably wouldn't want their drivers held up by even a few minutes by the occasional random supercar cruising through.
I'm curious as well but don't forget, we're going to be seeing Supercharging V3 next year, surely the Roadster will take advantage of those!
 

Bobby Garrity

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#7
Yeah there's no way the Roadsters will be allowed to use Megachargers, for the exact reason Ryan mentioned. Plus the Superchargers are located and tailored towards consumers, so the Megachargers won't even be beneficial, especially after V3 is out.
 

Michael Russo

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#8
What is unclear to me is to what extent all of us current owners will see benefit of V3... with no hardware change to existing vehicles... anybody thinks they’re capable of handling more than the current 115 kW? And is yes, how much, 150 kW? More??
 

Bobby Garrity

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#9
What is unclear to me is to what extent all of us current owners will see benefit of V3... with no hardware change to existing vehicles... anybody thinks they’re capable of handling more than the current 115 kW? And is yes, how much, 150 kW? More??
Probably little to nothing with current hardware. Although it shouldn't be long until Model S and X switch to the 2170 cells, and may be able to offer larger battery packs. Let's say they make 120kWh packs. Using the same method as in the first post, such a car should be able to charge at 192kW.
 

PNWmisty

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#10
What is unclear to me is to what extent all of us current owners will see benefit of V3... with no hardware change to existing vehicles... anybody thinks they’re capable of handling more than the current 115 kW? And is yes, how much, 150 kW? More??
The "current 115 kW" is only that if you are not sharing a charger circuit and the battery is ready to accept the full amount. So, I imagine V3 will be better in those circumstances when you might otherwise be sharing a circuit.
 

MachV

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#11
Some simple math reveals that the new Roadster should be capable of charging at at least 320kW. Let's take a look:

-The Long Range Model 3, with a 75kWh battery, can achieve a peak charging rate of 120kW on a Supercharger
-The base model new Roadster has a 200kWh battery
-(120kW/75kWh) * 200kWh = 320kW

So this means that even if there are no battery improvements at all compared to the current Model 3, the new Roadster should a reach peak charging rate of 320kW assuming no other bottlenecks and a fast enough charger.
.
um..NO

your math assums that they design the car such that it takes the same charging time for either model. that's not how it works - Lets say the model 3 LR takes 40min to charge up its 75kwh battery. if the roadsters battery is 3x bigger, it will take 3x longer! your math assumes it takes the same 40 minutes to charge up a much larger battery, which is not how charging works. if they change from 400vdc to 800vdc they should be able to charge roughly 2x faster. but i don't think that's whats happening. besides the supercharger is 400vdc based, not 800vdc like the Taycan
 

garsh

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#12
if the roadsters battery is 3x bigger, it will take 3x longer!
It's more complicated that that. Each individual battery cell has a maximum current that it can accept. This is what fundamentally limits the charging time. Two vehicles whose battery packs are designed using the same type of cell will take the same amount of time to supercharge (assuming the supercharger can supply enough energy to maximize the current to each cell).
  • This means that a Model 3 SR can charge from 10% -> 90% in the same amount of time that a Model 3 LR can charge from 10% -> 90%.
  • The corollary here is that this ALSO means that the charge rate (in either kW or miles per hour of charging) will be lower for the SR.
If the Roadster is designed using the same battery cells as the Model 3 (very likely), and if a supercharger is designed to be able to deliver enough power to compensate for the larger battery pack in a Roadster (unlikely - it would need to be a 500 kW supercharger), then a Roadster could supercharge in the same amount of time (that is, in terms of battery percentage), and at a much faster rate (in terms of kW or miles per hour of charging).

I think it's quite possible that the Roadster will offer dual chargers as an option, so that it can make use of two superchargers at the same time in order to reach that 500kW charging rate, and thus charge just as quickly as a Model 3. :cool:
 

wst88

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#13
um..NO

your math assums that they design the car such that it takes the same charging time for either model. that's not how it works - Lets say the model 3 LR takes 40min to charge up its 75kwh battery. if the roadsters battery is 3x bigger, it will take 3x longer! your math assumes it takes the same 40 minutes to charge up a much larger battery, which is not how charging works. if they change from 400vdc to 800vdc they should be able to charge roughly 2x faster. but i don't think that's whats happening. besides the supercharger is 400vdc based, not 800vdc like the Taycan
You are correct assuming the same charging rate. However I think the point is that the larger the battery, the more cells, the faster you can charge. So if you double the size of your battery, it can accept a faster charge in KW.

ROUGH NUMBERS - Assuming charging rate decreases as you approach 100%
100KW battery = Chargers in 50 min @ a V2 Charger 120K Max
200KW battery = Chargers in 50 min @ a V3 Charger 320K Max

So you can charge the battery at over the same time period, however you are getting 600 miles vs 300 miles.

Sound Right?
 

MachV

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#14
You are correct assuming the same charging rate. However I think the point is that the larger the battery, the more cells, the faster you can charge. So if you double the size of your battery, it can accept a faster charge in KW.

ROUGH NUMBERS - Assuming charging rate decreases as you approach 100%
100KW battery = Chargers in 50 min @ a V2 Charger 120K Max
200KW battery = Chargers in 50 min @ a V3 Charger 320K Max

So you can charge the battery at over the same time period, however you are getting 600 miles vs 300 miles.

Sound Right?
this makes sense. also helps to understand why the base models charger only charges at 32A while the LR or AWD charges at 40-48A. Charging is done in parallel
 

Bobby Garrity

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#15
Well folks, since making this thread we've learned that the Model 3 can charge even faster, at 250kW! So let's do the math again:
(250kW/75kWh) * 200kWh = 666kW

Damn.