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The Tesla superchargers currently charge at around 2% a minute up until about 80% which is 40 minutes to hit 80%. Tesla is advertising 400 miles in 30 minutes w

by nimos 9y ago

The Tesla superchargers currently charge at around 2% a minute up until about 80% which is 40 minutes to hit 80%. Tesla is advertising 400 miles in 30 minutes which is 80% of the 500 mile capacity. What is so hard to believe about a 33% improvement over a couple year old tech that is a couple years from release? Here are current industrial/transportation/residential electric prices in US [0]. They think Tesla will pay 40c a kwh??? What a joke. Sure if you look at constant demand facilities and extrapolate their pricing model with low average demand to megachargers you can come up with a ridiculous number. You can literally run diesel generators and generate electricity for a lower cost. This is so hysterically asinine I can't believe Bloomberg published this article. Not to mention a huge amount of charging can happen overnight when drivers are sleeping and electricity prices/demand are super low. Pushing a lot of power through a wire is a solved problem. So what they need to push 10x through one connection instead of over 10. We are talking about a modest increase in % charge rates. That is what matters. All else equal you can charge a percent of your battery capacity not some arbitrary fixed number. This is an embarrassingly poor article. I think the one the worst things about the current tech shortage is now we have all these arts/business majors doing technology writing larping like they know the difference between a watt and an amp. [0]https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...

jepler 9y ago
Look at charging rates in watts (watt hours per hour) instead of in percentage; those semis have much larger capacity batteries, so they need a higher charging rate in W to charge 80% in 30 minutes than a vehicle with a smaller battery.
- cperciva 9y ago
  They don't have larger capacity batteries. They have batteries with more cells. Sure, the total charging rate is a higher Wattage, but you can charge cells in parallel. The scaling here is exactly the same as with the "larger battery" versions of the Model S having more horsepower; higher capacity = higher throughput when you're dealing with battery banks.
  - kumarvvr 9y ago
    Wait, are you concluding that having batteries with more cells is not the same as increasing the capacity of the system? For any battery system, the capacity is the product of the number of cells and capacity per cell.
    - cperciva 9y ago
      My point is that having a larger capacity battery automatically increases the wattage at which you can recharge. It's not like a gas tank where a 100L tank takes longer to refill than a 50L tank.
      - kumarvvr 9y ago
        No, capacity of the battery isn't what determines the wattage at which you can recharge. It's the physical power supply constraints. If I have a 250v, 25 kWh battery, I can charge it at 250 V, 100 Amps for 1 hour or at 250V, 1000 Amps for 6 minutes. What charging rate I select depends on the voltage and chemistry in the battery. Can the battery support charging at such a rate. The charging current rate is limited to the max operating current of the battery. If the above battery can supply a max current of say 50 amps, then you will have a max charge rate of 250V, 50 Amps for 2 hours.
        petre 9y ago
        What makes it confusing is that the charging rates are given as 10C, meaning 10% of nameplate capacity.
        kumarvvr 9y ago
        Might be fererring to nameplate power capacity.
        zAy0LfpBZLC8mAC 9y ago
        nC means n*capacity/time, so 10C for 10kWh is 100kW
- foota 9y ago
  I would imagine that the difficulty in charging is proportional to the cell's capacity, so charging 2*n cell shouldn't be any harder than charging n cells, as long as the cell's capacity is the same. If you increase the capacity of a cell, then you might have to innovate.
mhermher 9y ago
Did you seriously just compare rates by percentage across different batteries of probably different capacities? Anything to save face for Tesla I guess.
- nimos 9y ago
  Of course I did. Why wouldn't I? They are all battery PACKS. Maybe I didn't make that clear but I think that is a well known fact that Tesla batteries are made up of a collection of cells. You have 100 of battery X and you go to 1000 of battery X you can charge 10X more watt hours but the same %.
  - kumarvvr 9y ago
    You are so right, the same percentage but at 10 times the current when compared to the former case. Then the question is "Do the superchargers allow for that much current?"
    - kalleboo 9y ago
      > Then the question is "Do the superchargers allow for that much current?" They don't, which is why Tesla announced their plans to build new "Megachargers" https://www.teslarati.com/tesla-semi-megacharger-charging-port-close-up-look/ https://www.teslarati.com/tesla-semi-megacharger-charging-po...
extrapickles 9y ago
Truckers are even required to take a federally mandated 30 minute break[0] during the day, during which the truck can be recharging. Industrial applications already consume much more power than an entire Megacharger site, so supplying the charger with power is an already solved problem. Getting power from the charger the truck is again, a solved problem in the industrial space. I can order an off the shelf industrial connector [1] that does 1000v @ 400A, which means you might need two of them. Truckers already use 2 pumps to fill their truck, so even that is not out of place. [0] https://www.fmcsa.dot.gov/regulations/hours-service/summary-hours-service-regulations https://www.fmcsa.dot.gov/regulations/hours-service/summary-... [1] https://www.connector-techals.com.au/manufacturer/rauscher-stoecklin https://www.connector-techals.com.au/manufacturer/rauscher-s...
- firebones 9y ago
  The regulatory info only gives information on the way things should be with regard to how truckers and the interstate highway system works, but I would suggest that before you invest on this hypothesis, talk to some truckers earning $0.50 per mile. And look at where semis actually park when they're taking their 30 minute and 11 hour breaks, before deciding how fast this transition will occur and how much infrastructure will have to be in place along the major cross country interstates like I-70, I-80, I-35, etc., before a trucking company or an independent trucker decides to go all in on electric. (I don't know the answer, but I strongly suspect that regulations are not going to be the driver of the adoption of this tech. Short haul or "hot shot" could be better suited for electric and autonomous. Show me some progress there first and I will buy into some actual disruption. If you want a research assignment, take to the interstate back and forth across a couple of flyover states and stop and see where the trucks actually are.)
  - lucaspiller 9y ago
    I’d argue that these trucks would be a much better fit in Europe than the US. Here truckers can drive a maximum of 9.5 hours a day with a 45 minute break. These are mandated by law and the pentalties are severe for going over these limits. The range also lends itself nicely to this. Over the course of a day a trucker would drive a maximum of 855km (they are limited to 90/h), so with a short fast charge during their break the 500 mile version could easily achieve this, then over night it could be charged slower.
baddox 9y ago
All these EVs use roughly the same small cells, right? Essentially thousands of the same cells used in hobbyist RC aircraft (with which I’m fairly familiar)? Unless I’m mistaken, each little cell should theoretically be chargeable in parallel, limited only by heat, massively parallel wiring, and the one massive input carrying ridiculous current. In theory, if one cell takes 30 minutes to charge, all cells could be charged in parallel in 30 minutes. Obviously this is ignoring the challenges I mentioned, which generally don’t apply to the relatively small RC aircraft with which I have experience.
- kumarvvr 9y ago
  If all of them are connected in parallel, then you are right. It's like filling an array of glasses in the rain. However the superchargers connect to the vehicle through a power port, which is relatively small. So it may not have as many parallel connections. You could split the charging to individual cells inside the car, allowing for parallel charging of all the cells simultaneously, but that means that the supercharger has to handle the cumulative power requirement of all the cells in parallel. So if you have 500 50W cells, then the super charger has to have the capacity to handle 25 kW of power. And that much power requires some very bulky cabling, even with a 3-phase supply.
  - simonsarris 9y ago
    The parallel connections are visible: https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-Charging-Port-2.jpg https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-...
  - petre 9y ago
    Yup, definitely 3 phase. But then it has to supply a charger or an array of chargers on the vehicle that convert the power to DC, leading to increased bulk and costs. So we're back to the 501 terminal plug again.
  - baddox 9y ago
    Perhaps they’re looking into some even superer superchargers for the tractors. It’s a shame they apparently publicly abandoned the hot-swap battery system, although I can’t imagine they’re not still working on it, especially for the tractors.
colordrops 9y ago
It's typical anti-Tesla propaganda.
- whamlastxmas 9y ago
  Agreed. I don't know why there's so much anti-Tesla sentiment on HN.
  - erikpukinskis 9y ago
    Smart people like to try to take down the smartest person in the room.
kumarvvr 9y ago
Comparing on a percentage point basis, you have to ensure that the underlying physical system is equivalent, in this case, the capacity of the batteries. Current superchargers charge at 2% / minute. I am assuming that's the maximum rate of charge, given the current supercharger infrastructure. Lets assume that 2% / min is, say, at a 100 kW power level. When charging a truck, assuming the supercharger technology isn't changed, the charging will still be at 100 kW power level. So if the truck has 10 times the battery capacity, then the equivalent %age rate of charge will be 0.2%, not the same 2% as the capacity of the battery to be charged has changed. Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger, or have some sort of port in the truck to which a special connector is connected to transfer huge amounts of power safely, not unlike a dock at the under side of the truck, or maybe the front.
- chrishacken 9y ago
  I'm no battery expert, but is it possible that they have several battery compartments that can all be charged simultaneously? Thus reducing charge time? Edit: Just read the latter part of your post after I wrote this. I think this is the most likely scenario. "Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger,"
  - kumarvvr 9y ago
    Yes it's possible. We could have a power port like a VGA cable with say 10 or 20 independent supplies, simultaneously charging the different battery units. However those connectors will be very bulky and heavy. Maybe Elon is thinking of a mechanized system, say a power robotic arm sort of thing, or maybe tech similar to the instant battery changing station he demoed a few years back.
  - wlesieutre 9y ago
    They do call it a "megacharger," and the port appears to have multiple connections https://www.teslarati.com/tesla-semi-megacharger-charging-port-close-up-look/ https://www.teslarati.com/tesla-semi-megacharger-charging-po...
sametmax 9y ago
Half of the stories about Musk projects are just rambling about how what he's doing won't work. I find that doing something that matters in life is not just hard because the task is difficult. It's hard because of all the people that gets in your way. It's already painful to see people doing nothing by themself. Or even not helping the cause of others. But it's infuriating to see how much energy they spend to go against your attempts.
- puranjay 9y ago
  I'm just constantly surprised and exhausted at the kind of pessimism and cynicism on display in any Tesla thread. Even people who have no stake in the company or its competitors feel compelled to chime in just to say "it won't work!" I don't get it. For better or for worse, Tesla has made the idea of electric cars feasible to the mainstream. Surely, that can't be a bad thing. Why knock down the idea so aggressively?
  - koonsolo 9y ago
    I'm starting my own business myself, and I notice there are fundamentally 2 kinds of people. One are the risk takers. Who know risks are involved, but do it anyway, sometimes against all odds, because the payoff (in any form) is big or huge. The risk is worth it for them. Then you have the conservatives, who just don't want to fail. They take no risk, don't step out of their comfort zone, because they might fall down, they might fail. They want to be like all other people, average and safe. I'm not saying either of them is good or bad. They just have a different take on life. I think conservatives are happier. Problem is that when a conservative sees a risk taker in action, they don't understand it. They see all the possible ways on how this thing can fail. They ask why these risk takers don't see how this can fail. Point is that the risk takers do know how things can fail, but do it anyway (ok, sometimes you do have stupid people who don't know). If it fails, they can proudly say "See I knew it! How stupid was that". Conservatives like to remain in their safe zone, where they know how things go. The risk takers always want to change things. If anyone has another take on this, I would be glad to hear it.
    - 9y ago
avar 9y ago
They don't even need the 33% improvement. They could just add that much battery and fake the charge rate by misinforming the user about the charge rate. I.e. say it took 30 minutes to get from 0% to 80%, but really you went from 30% to 80%, the car just shuts down at 30%. They already have firmware unlocked battery capacity in their currently shipping cars, so this isn't some wild conjuncture. The margins on these vehicles are huge, they can just decide they'd like to pay for marketing by cutting into some of those and shipping more batteries with each vehicle.
bogomipz 9y ago
>"The Tesla superchargers currently charge at around 2% a minute up until about 80% which is 40 minutes to hit 80%." I am curious what exactly happens at 80%, does that 2% a minute rate drop off precipitously? If so what is the reason for that?
- flyingspork 9y ago
  Lithium Ion batteries are generally charged using a two step process of constant current then constant voltage. https://www.digikey.com/en/articles/techzone/2012/nov/constant-voltageconstant-current-devices-optimize-li-ion-battery-charging-for-energy-harvesting https://www.digikey.com/en/articles/techzone/2012/nov/consta... If 80% is the set point to switch over from constant-current to constant-voltage, then yes, the charge rate will drop continuously until it reaches full charge.

by nimos 9y ago

jepler 9y ago

Look at charging rates in watts (watt hours per hour) instead of in percentage; those semis have much larger capacity batteries, so they need a higher charging rate in W to charge 80% in 30 minutes than a vehicle with a smaller battery.

cperciva 9y ago
They don't have larger capacity batteries. They have batteries with more cells. Sure, the total charging rate is a higher Wattage, but you can charge cells in parallel. The scaling here is exactly the same as with the "larger battery" versions of the Model S having more horsepower; higher capacity = higher throughput when you're dealing with battery banks.
- kumarvvr 9y ago
  Wait, are you concluding that having batteries with more cells is not the same as increasing the capacity of the system? For any battery system, the capacity is the product of the number of cells and capacity per cell.
  - cperciva 9y ago
    My point is that having a larger capacity battery automatically increases the wattage at which you can recharge. It's not like a gas tank where a 100L tank takes longer to refill than a 50L tank.
    - kumarvvr 9y ago
      No, capacity of the battery isn't what determines the wattage at which you can recharge. It's the physical power supply constraints. If I have a 250v, 25 kWh battery, I can charge it at 250 V, 100 Amps for 1 hour or at 250V, 1000 Amps for 6 minutes. What charging rate I select depends on the voltage and chemistry in the battery. Can the battery support charging at such a rate. The charging current rate is limited to the max operating current of the battery. If the above battery can supply a max current of say 50 amps, then you will have a max charge rate of 250V, 50 Amps for 2 hours.
      - petre 9y ago
        What makes it confusing is that the charging rates are given as 10C, meaning 10% of nameplate capacity.
        kumarvvr 9y ago
        Might be fererring to nameplate power capacity.
        zAy0LfpBZLC8mAC 9y ago
        nC means n*capacity/time, so 10C for 10kWh is 100kW
foota 9y ago
I would imagine that the difficulty in charging is proportional to the cell's capacity, so charging 2*n cell shouldn't be any harder than charging n cells, as long as the cell's capacity is the same. If you increase the capacity of a cell, then you might have to innovate.

mhermher 9y ago

Did you seriously just compare rates by percentage across different batteries of probably different capacities? Anything to save face for Tesla I guess.

nimos 9y ago
Of course I did. Why wouldn't I? They are all battery PACKS. Maybe I didn't make that clear but I think that is a well known fact that Tesla batteries are made up of a collection of cells. You have 100 of battery X and you go to 1000 of battery X you can charge 10X more watt hours but the same %.
- kumarvvr 9y ago
  You are so right, the same percentage but at 10 times the current when compared to the former case. Then the question is "Do the superchargers allow for that much current?"
  - kalleboo 9y ago
    > Then the question is "Do the superchargers allow for that much current?" They don't, which is why Tesla announced their plans to build new "Megachargers" https://www.teslarati.com/tesla-semi-megacharger-charging-port-close-up-look/ https://www.teslarati.com/tesla-semi-megacharger-charging-po...

extrapickles 9y ago

Truckers are even required to take a federally mandated 30 minute break[0] during the day, during which the truck can be recharging. Industrial applications already consume much more power than an entire Megacharger site, so supplying the charger with power is an already solved problem. Getting power from the charger the truck is again, a solved problem in the industrial space. I can order an off the shelf industrial connector [1] that does 1000v @ 400A, which means you might need two of them. Truckers already use 2 pumps to fill their truck, so even that is not out of place. [0] https://www.fmcsa.dot.gov/regulations/hours-service/summary-hours-service-regulations https://www.fmcsa.dot.gov/regulations/hours-service/summary-... [1] https://www.connector-techals.com.au/manufacturer/rauscher-stoecklin https://www.connector-techals.com.au/manufacturer/rauscher-s...

firebones 9y ago
The regulatory info only gives information on the way things should be with regard to how truckers and the interstate highway system works, but I would suggest that before you invest on this hypothesis, talk to some truckers earning $0.50 per mile. And look at where semis actually park when they're taking their 30 minute and 11 hour breaks, before deciding how fast this transition will occur and how much infrastructure will have to be in place along the major cross country interstates like I-70, I-80, I-35, etc., before a trucking company or an independent trucker decides to go all in on electric. (I don't know the answer, but I strongly suspect that regulations are not going to be the driver of the adoption of this tech. Short haul or "hot shot" could be better suited for electric and autonomous. Show me some progress there first and I will buy into some actual disruption. If you want a research assignment, take to the interstate back and forth across a couple of flyover states and stop and see where the trucks actually are.)
- lucaspiller 9y ago
  I’d argue that these trucks would be a much better fit in Europe than the US. Here truckers can drive a maximum of 9.5 hours a day with a 45 minute break. These are mandated by law and the pentalties are severe for going over these limits. The range also lends itself nicely to this. Over the course of a day a trucker would drive a maximum of 855km (they are limited to 90/h), so with a short fast charge during their break the 500 mile version could easily achieve this, then over night it could be charged slower.

baddox 9y ago

All these EVs use roughly the same small cells, right? Essentially thousands of the same cells used in hobbyist RC aircraft (with which I’m fairly familiar)? Unless I’m mistaken, each little cell should theoretically be chargeable in parallel, limited only by heat, massively parallel wiring, and the one massive input carrying ridiculous current. In theory, if one cell takes 30 minutes to charge, all cells could be charged in parallel in 30 minutes. Obviously this is ignoring the challenges I mentioned, which generally don’t apply to the relatively small RC aircraft with which I have experience.

kumarvvr 9y ago
If all of them are connected in parallel, then you are right. It's like filling an array of glasses in the rain. However the superchargers connect to the vehicle through a power port, which is relatively small. So it may not have as many parallel connections. You could split the charging to individual cells inside the car, allowing for parallel charging of all the cells simultaneously, but that means that the supercharger has to handle the cumulative power requirement of all the cells in parallel. So if you have 500 50W cells, then the super charger has to have the capacity to handle 25 kW of power. And that much power requires some very bulky cabling, even with a 3-phase supply.
- simonsarris 9y ago
  The parallel connections are visible: https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-Charging-Port-2.jpg https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-...
- petre 9y ago
  Yup, definitely 3 phase. But then it has to supply a charger or an array of chargers on the vehicle that convert the power to DC, leading to increased bulk and costs. So we're back to the 501 terminal plug again.
- baddox 9y ago
  Perhaps they’re looking into some even superer superchargers for the tractors. It’s a shame they apparently publicly abandoned the hot-swap battery system, although I can’t imagine they’re not still working on it, especially for the tractors.

colordrops 9y ago

It's typical anti-Tesla propaganda.

whamlastxmas 9y ago
Agreed. I don't know why there's so much anti-Tesla sentiment on HN.
- erikpukinskis 9y ago
  Smart people like to try to take down the smartest person in the room.

kumarvvr 9y ago

Comparing on a percentage point basis, you have to ensure that the underlying physical system is equivalent, in this case, the capacity of the batteries. Current superchargers charge at 2% / minute. I am assuming that's the maximum rate of charge, given the current supercharger infrastructure. Lets assume that 2% / min is, say, at a 100 kW power level. When charging a truck, assuming the supercharger technology isn't changed, the charging will still be at 100 kW power level. So if the truck has 10 times the battery capacity, then the equivalent %age rate of charge will be 0.2%, not the same 2% as the capacity of the battery to be charged has changed. Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger, or have some sort of port in the truck to which a special connector is connected to transfer huge amounts of power safely, not unlike a dock at the under side of the truck, or maybe the front.

chrishacken 9y ago
I'm no battery expert, but is it possible that they have several battery compartments that can all be charged simultaneously? Thus reducing charge time? Edit: Just read the latter part of your post after I wrote this. I think this is the most likely scenario. "Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger,"
- kumarvvr 9y ago
  Yes it's possible. We could have a power port like a VGA cable with say 10 or 20 independent supplies, simultaneously charging the different battery units. However those connectors will be very bulky and heavy. Maybe Elon is thinking of a mechanized system, say a power robotic arm sort of thing, or maybe tech similar to the instant battery changing station he demoed a few years back.
- wlesieutre 9y ago
  They do call it a "megacharger," and the port appears to have multiple connections https://www.teslarati.com/tesla-semi-megacharger-charging-port-close-up-look/ https://www.teslarati.com/tesla-semi-megacharger-charging-po...

sametmax 9y ago

Half of the stories about Musk projects are just rambling about how what he's doing won't work. I find that doing something that matters in life is not just hard because the task is difficult. It's hard because of all the people that gets in your way. It's already painful to see people doing nothing by themself. Or even not helping the cause of others. But it's infuriating to see how much energy they spend to go against your attempts.

puranjay 9y ago
I'm just constantly surprised and exhausted at the kind of pessimism and cynicism on display in any Tesla thread. Even people who have no stake in the company or its competitors feel compelled to chime in just to say "it won't work!" I don't get it. For better or for worse, Tesla has made the idea of electric cars feasible to the mainstream. Surely, that can't be a bad thing. Why knock down the idea so aggressively?
- koonsolo 9y ago
  I'm starting my own business myself, and I notice there are fundamentally 2 kinds of people. One are the risk takers. Who know risks are involved, but do it anyway, sometimes against all odds, because the payoff (in any form) is big or huge. The risk is worth it for them. Then you have the conservatives, who just don't want to fail. They take no risk, don't step out of their comfort zone, because they might fall down, they might fail. They want to be like all other people, average and safe. I'm not saying either of them is good or bad. They just have a different take on life. I think conservatives are happier. Problem is that when a conservative sees a risk taker in action, they don't understand it. They see all the possible ways on how this thing can fail. They ask why these risk takers don't see how this can fail. Point is that the risk takers do know how things can fail, but do it anyway (ok, sometimes you do have stupid people who don't know). If it fails, they can proudly say "See I knew it! How stupid was that". Conservatives like to remain in their safe zone, where they know how things go. The risk takers always want to change things. If anyone has another take on this, I would be glad to hear it.
  - 9y ago

avar 9y ago

They don't even need the 33% improvement. They could just add that much battery and fake the charge rate by misinforming the user about the charge rate. I.e. say it took 30 minutes to get from 0% to 80%, but really you went from 30% to 80%, the car just shuts down at 30%. They already have firmware unlocked battery capacity in their currently shipping cars, so this isn't some wild conjuncture. The margins on these vehicles are huge, they can just decide they'd like to pay for marketing by cutting into some of those and shipping more batteries with each vehicle.

bogomipz 9y ago

>"The Tesla superchargers currently charge at around 2% a minute up until about 80% which is 40 minutes to hit 80%." I am curious what exactly happens at 80%, does that 2% a minute rate drop off precipitously? If so what is the reason for that?

flyingspork 9y ago
Lithium Ion batteries are generally charged using a two step process of constant current then constant voltage. https://www.digikey.com/en/articles/techzone/2012/nov/constant-voltageconstant-current-devices-optimize-li-ion-battery-charging-for-energy-harvesting https://www.digikey.com/en/articles/techzone/2012/nov/consta... If 80% is the set point to switch over from constant-current to constant-voltage, then yes, the charge rate will drop continuously until it reaches full charge.