Could home charging one day be quicker?

Quant · Jan 18, 2016

First off.....my apologies, because I don't where to post this question.

I don't know if it it's been asked and answered before either....I did look up the first 3-4 pages of threads on charging and could not find any hints ! So, with that said, here's my question, please :

1. Re home chargers for a Tesla, and also for a supercharger, with an eye to the future, is there is theoretical limit on how quickly Tesla could potentially engineer more efficient charging. For example, would it ever be possible, in theory, for the dual chargers at home, to ever charge say within 10 minutes? Meaning a FULL charge, when a battery is almost completely depleted ? In theory ! Or does theory say not possible? I mean from the standpoint of physics and electrical engineering theory.

2. And again, same question for Superchargers. I believe the current time is about 20 minutes for a partial charge. Could that ever approach, say 5 minutes, in theory ?

I spend about 50 % of my time now traveling outside the US ( just for pleasure!), and no longer need or live in a single family home. And in Austin, Texas, and area around it, there are very few Superchargers. I would love to get rid of my MB's and move to Tesla, but feel both constrained and uneducated on the long-term theoretical limits. So, I'm just trying to understand where the technology - in theory - could potentially be 3-5 years from now. Again, Trying to understand the theoretical limits.....because I am confident Elon and team will try to get there as quickly as technically possible/ feasible.

Thanks for feedback from those who have some technical expertise in this area.

MarcG · Jan 18, 2016

Quant said:
First off.....my apologies, because I don't where to post this question.

I don't know if it it's been asked and answered before either....I did look up the first 3-4 pages of threads on charging and could not find any hints ! So, with that said, here's my question, please :

1. Re home chargers for a Tesla, and also for a supercharger, with an eye to the future, is there is theoretical limit on how quickly Tesla could potentially engineer more efficient charging. For example, would it ever be possible, in theory, for the dual chargers at home, to ever charge say within 10 minutes? Meaning a FULL charge, when a battery is almost completely depleted ? In theory ! Or does theory say not possible? I mean from the standpoint of physics and electrical engineering theory.

2. And again, same question for Superchargers. I believe the current time is about 20 minutes for a partial charge. Could that ever approach, say 5 minutes, in theory ?

I spend about 50 % of my time now traveling outside the US ( just for pleasure!), and no longer need or live in a single family home. And in Austin, Texas, and area around it, there are very few Superchargers. I would love to get rid of my MB's and move to Tesla, but feel both constrained and uneducated on the long-term theoretical limits. So, I'm just trying to understand where the technology - in theory - could potentially be 3-5 years from now. Again, Trying to understand the theoretical limits.....because I am confident Elon and team will try to get there as quickly as technically possible/ feasible.

Thanks for feedback from those who have some technical expertise in this area.

First off, this post is probably best suited as a new thread. That being said, here are my answers to your questions:

1. With the existing dual chargers, we're limited to 20kW of power. Assuming a battery of 40kWh being the smallest battery ever provided by Tesla, which is really a 60kWh physical battery but limited to 40kWh, there's a theoretical minimum of 2 hours assuming 100% efficiency in charging. 3 hours for the 60kWh battery, 3.5 hours for the 70kWh, etc. Now if Tesla provided onboard chargers that support more than 20kW of peak power, we could see that home charging time reduced - however it is unlikely given the few use cases (destination charging) don't justify the increased cost and power needs. Case in point: the Model X ships with an onboard charger with lower peak power (and I think I read there was a hidden option to choose a slightly more powerful one, but still less than 20kW).

2. At Superchargers you're limited by two things: peak power the SC can provide, and the maximum charging rate of the battery. IF they both increase dramatically, we could see 5-minute charging times in the not-so-soon future (the battery charging rate being the more difficult problem to solve).

mikeash · Jan 19, 2016

I know you didn't ask, but current charging rates are good enough for probably 99% of drivers. If you can charge at home and have superchargers along your long-distance driving routes, you're all set. Plug in at night and you're full in the morning no matter how depleted the battery was, and that's without dual chargers. In the rare event that you drive more than 200 miles in a day, the superchargers take care of that. Note that you don't need them to be particularly close to where you live. You want them to be about 100-150 miles away from where you live, in the directions that you'll travel. Charging time here is usually just enough to have a nice little break and stretch before you get back to driving. Faster supercharging times would be nice, but wouldn't make a huge difference.

If you can't charge at home, then the EV experience is not going to be very fun, no matter how fast charging is. Even if you could charge the vehicle at a supercharger instantaneously, you'd still have to go visit one pretty frequently (about twice as often as you'd fill up a gas car) and that's going to be pretty annoying. If you're driving outside supercharger coverage then you're going to have a harder time of it. So the key factors really are availability of charging by getting charging at home and building out the supercharger network. Charging speed is much less important compared to that.

Home charging speed is pretty much just limited by expense. You need equipment to convert AC power to DC power at the right voltage for charging. The more power you want to convert, the more equipment you need. There's nothing preventing you from installing, say, a 50kW CHAdeMO charger in a home garage right now, and using that to charge a Model S from zero to 100% in maybe an hour and a half. Of course, a CHAdeMO station will cost probably $20,000, as compared to $1,500 or so for a typical installed Tesla HPWC. If you felt like plunking down $100,000 or so, you might be able to convince Tesla to sell you a supercharger cabinet to install at home. You'd also have to upgrade your home electrical service to three phase, 480V, and however many hundreds of amps it would need.

But really, while this is certainly an interesting topic to discuss, in terms of the actual utility of the car, don't worry about it. It's good enough right now.

green1 · Jan 19, 2016

The real limit with home charging is how much your house can provide anyway.

My entrance from the power company is 240v 100a some people only have 240v 60a and new houses around here are still only built at 240v 200a. This has to cover all electrical needs of the house, not just the car. so 240v 80a charging is a significant load on even the largest home panels, adding even more would require a whole lot more power to the house from the utility, which will be many thousands of dollars at a bare minimum.

It's also pretty tough to imagine a scenario where home charging at 240v 80a wouldn't be enough, that's enough to fully charge the car in under 4 hours, from completely dead, to completely full, neither of which are extremes you're likely to encounter often at home.

jerry33 · Jan 19, 2016

As far as the physics go, the rate of charge will always reduce as the battery SOC approaches full. Having a larger battery lengthens the fastest rate time. That said, a Supercharger charges at up to 135 kW. It going to be hard to talk the power company and inspector into it. And it won't be cheap.

jcaspar · Jan 19, 2016

To give you an idea of the cost, here is a link to a CHAdeMO "fast charger" for 13,000$. This only produces 20kW and requires 32A, 3-phase power which is likely not available in a residential area. A Tesla supercharger produces up to 135kW.

Interesting thought but totally impractical. Most owners find they don't even need the dual charger upgrade to go from 29 to 58 miles per hour, and it is only 2000$.

tinm · Jan 19, 2016

What I would truly love to do is take a baby step with solar at the house.

I work in a home office, so my car is here most of the day. What I have in mind is the minimal amount of solar panels (2? 4?) that would enable me to have say 240V 24A DC (yes, DC) power straight from the panels, straight into the car, like a "baby Supercharger."

I'm thinking of a solar array dedicated to charging the car itself, nothing else, no inverter, no grid-tie, no connection whatsoever to the rest of the house. House would stay on grid power for now. But phase one of the project would be as cheap as possible, with the goal being, charge the car via the sun during the day, period. If car needs more charging at night, charge via grid-powered HPWC. But during day, it pulls straight from solar power with as little in-between the sun and the car as possible.

Is that doable?

tga · Jan 19, 2016

tinm said:
What I would truly love to do is take a baby step with solar at the house.

I work in a home office, so my car is here most of the day. What I have in mind is the minimal amount of solar panels (2? 4?) that would enable me to have say 240V 24A DC (yes, DC) power straight from the panels, straight into the car, like a "baby Supercharger."

I'm thinking of a solar array dedicated to charging the car itself, nothing else, no inverter, no grid-tie, no connection whatsoever to the rest of the house. House would stay on grid power for now. But phase one of the project would be as cheap as possible, with the goal being, charge the car via the sun during the day, period. If car needs more charging at night, charge via grid-powered HPWC. But during day, it pulls straight from solar power with as little in-between the sun and the car as possible.

Is that doable?

It's going to be really difficult. You need a DC-DC converter/charge controller that can convert the DC voltage supplied by the panels to the correct voltage and amperage required by the battery to match the battery's constant current/constant voltage charge algorithm. The custom electronics you need will probably be much more expensive than a mass-market solar inverter.

It's probably significantly easier to just use a grid-tie inverter and plug in the car when the sun is shining.

On the other hand, it's probably just as easy to charge whenever convenient and let the grid-tie system offset a dirty peaking plant's CO2 output.

CHG-ON · Jan 19, 2016

Even though I love my MS to death, I would not have bought it if I could not charge at home. As previously noted, it would be a big PIA to go hang out at SpC and wait. Some do it. I don't know how they stand it. mikeash summed it up the best.

Quant · Jan 20, 2016

MarcG said:
First off, this post is probably best suited as a new thread. That being said, here are my answers to your questions:

1. With the existing dual chargers, we're limited to 20kW of power. Assuming a battery of 40kWh being the smallest battery ever provided by Tesla, which is really a 60kWh physical battery but limited to 40kWh, there's a theoretical minimum of 2 hours assuming 100% efficiency in charging. 3 hours for the 60kWh battery, 3.5 hours for the 70kWh, etc. Now if Tesla provided onboard chargers that support more than 20kW of peak power, we could see that home charging time reduced - however it is unlikely given the few use cases (destination charging) don't justify the increased cost and power needs. Case in point: the Model X ships with an onboard charger with lower peak power (and I think I read there was a hidden option to choose a slightly more powerful one, but still less than 20kW).

2. At Superchargers you're limited by two things: peak power the SC can provide, and the maximum charging rate of the battery. IF they both increase dramatically, we could see 5-minute charging times in the not-so-soon future (the battery charging rate being the more difficult problem to solve).

Thanks, MarcG for your thoughts and feedback. That was extremely helpful...so much appreciated.

Re the technology and science behind the Tesla battery cell, the cell chemistry, and how they connect a bunch of cells and then create a battery pack, it is my understanding ( with my limited knowledge ) that Musk and his team also have a differentiated in-house developed software built into the packs, driving the efficiency ( among other things like safety cut offs) of the battery packs both during charging and during use. Elon has referred to this in public comments in the recent past....

I assume that your thoughts include that differentiated software component of Tesla battery pack optimization technology as a part of your projections for the future 3-5 years ? Of course, I do not expect you to be privy to how the software does what it does, but maybe what exactly the software does and where the theoretical limits of all of that, taken together would be .......

mgboyes · Jan 21, 2016

Quant said:
1. Re home chargers for a Tesla, and also for a supercharger, with an eye to the future, is there is theoretical limit on how quickly Tesla could potentially engineer more efficient charging. For example, would it ever be possible, in theory, for the dual chargers at home, to ever charge say within 10 minutes? Meaning a FULL charge, when a battery is almost completely depleted ? In theory ! Or does theory say not possible? I mean from the standpoint of physics and electrical engineering theory.

Your question seems slightly confused. Are you asking about whether charging can be faster, or more efficient? Today the most efficient (i.e. least energy needed overall) way to charge a Model S is at roughly 10-15kW. Slower charging wastes energy, and rapid DC charging creates waste heat so quickly that active cooling of the pack and the chargers is required. Yes, it's possible that in future charging efficiency could be increased to some degree, but ultimately electricity is pretty cheap so there's very little driving Tesla to do this.

If you're asking about whether or not home charging can be faster then the answer is "yes, but only at extremely high cost, and in reality there's no benefit to doing it". In reality charging at 10kW is more than enough for most people, especially in tandem with a supercharger network. I've actually been using a 2kW domestic outlet for the last 2 months, and it hasn't once been a problem.

The reason Tesla recently made the dual charger option on the Model S a "dealer fit" only option (i.e. they removed it from the design studio) is because nobody was ordering it, because it simply isn't necessary any more. This is a good thing.

If anything I would expect increasing coverage from the SC network will mean that average home charging speeds actually reduce over time.

Quant said:
2. And again, same question for Superchargers. I believe the current time is about 20 minutes for a partial charge. Could that ever approach, say 5 minutes, in theory ?

Tesla claims are "half-fill the car in 20 minutes" and "charge to 80% in 40 minutes" but if you check the small print in both cases they're talking about charging from 10-50 and from 10-80. Both these are absolutely achievable in the real world.

There is certainly scope for Tesla to improve this to some degree, most likely through enabling slower tapering (i.e. allowing the car to charge at full rate even when its battery is fuller). The advent of liquid cooled supercharger cables is undoubtedly a precursor here - I expect that without active cooling the SC connector might well overheat if asked to transmit 120kW for more than about 10 minutes.

But IMO 5 minute refills are a solution looking for a problem. Tesla built a battery swap station to enable exactly this and nobody used it. And getting literally down to 5 minutes is a very big ask indeed for a chemical battery, purely because of the immense amounts of cooling that the pack would need to stop it overheating. 80% filling a 100kWh pack in 5 minutes means power levels around 1MW. Even if it's 95% efficient (which is ambitious) then you are still dumping heat into the pack at a rate of 50kW, and the cooling system required to cope with that would be immense.

MarcG · Jan 21, 2016

Quant said:
Thanks, MarcG for your thoughts and feedback. That was extremely helpful...so much appreciated.

Re the technology and science behind the Tesla battery cell, the cell chemistry, and how they connect a bunch of cells and then create a battery pack, it is my understanding ( with my limited knowledge ) that Musk and his team also have a differentiated in-house developed software built into the packs, driving the efficiency ( among other things like safety cut offs) of the battery packs both during charging and during use. Elon has referred to this in public comments in the recent past....

I assume that your thoughts include that differentiated software component of Tesla battery pack optimization technology as a part of your projections for the future 3-5 years ? Of course, I do not expect you to be privy to how the software does what it does, but maybe what exactly the software does and where the theoretical limits of all of that, taken together would be .......

Pleasure! Glad to be able to shed some light, although I'm definitely not an expert in the field.

I did study electrical engineering but have been in software ever since, and I can tell you that solving the charging rates is far from being software-driven alone.

IMHO, the major breakthrough in EV adoption will happen with the advent of two things: ubiquity of REAL fast charging (not 45kW CHAdeMO or CCS), and the ability of batteries to charge at very fast rates. Think of the gas station model, which is critical to those who can't charge at home.

The former is starting to occur with superchargers but is far from enough (both in power and in location density) to be considered ubiquitous. The latter is the main limiting factor and can only be solved with much-improved battery chemistry that can take much higher C rates in charging than today's.

Until these two events occur, EVs will mostly be adopted by homeowners/those who can charge at home, and are patient enough to wait 30-60 minutes at a supercharger after having driven 1.5-2.5 hours. Or are buying an EV as a second car but are keeping their ICE vehicle. But I'm looking to a future where every single new car sold is 100% electric, and that will simply NOT happen until the two aforementioned events occur.

- - - Updated - - -

mgboyes said:
The reason Tesla recently made the dual charger option on the Model S a "dealer fit" only option (i.e. they removed it from the design studio) is because nobody was ordering it, because it simply isn't necessary any more.

But IMO 5 minute refills are a solution looking for a problem. Tesla built a battery swap station to enable exactly this and nobody used it.

I agree with all your post except for the two statements above.

On the first, having an onboard charger of 20kW instead of 10kW is very useful when traveling through regions away from home where there are no supercharger, only destination chargers. I can cite several examples where this has come in very handy for me and has made the traveling experience much less painful (it was slow as it were, but would have been twice as slow otherwise). Of course, if superchargers become ubiquitous as I mentioned in my reply to the OP above, this would become a moot point and we wouldn't even need onboard chargers any longer.

On the second point, 5-minute charging is definitively required when one can't charge at home. Which is the case for many people who live in cities of who don't own their homes. And I would venture to say the majority of people don't want to spend 30-60 minutes stopping to charge every 1.5 to 2.5 hours when doing a long road trip. As early adopters we are willing to do so because we're part of the movement and it feels great, but I highly doubt the vast majority wouldn't see this as an inconvenience relative to the existing gas-fillup model. You'll notice new entrants in the pure EV market (Porsche, Audi) are touting 10- or 15-minute charging for a reason: they want to attract the average buyer, not the early adopters only.

PS: the battery swap station was a half-hearted attempt by Tesla to take a stab at solving the long charging times. They only installed a single station between SF and LA, and they only took appointments by invitation to a subset of CA owners. Declaring this as a failure is not fair because it wasn't a true indicator of whether demand was there for such a model. However I still think the solution is dramatically reduced charging times, not battery swaps, as the latter comes with all sorts of issues such as battery ownership, degradation, etc.

mikeash · Jan 21, 2016

Seems to me that the solution for the hypothetical future where 100% of cars are electric is not extremely fast charging on the gas station model, but ubiquitous slow (L2) chargers. There's no particular reason that people who park in shared garages or even on the street can't charge overnight, the infrastructure just isn't in place yet. As EVs become more popular, I think that will begin to change.

mgboyes · Jan 21, 2016

MarcG said:
On the first, having an onboard charger of 20kW instead of 10kW is very useful when traveling through regions away from home where there are no supercharger, only destination chargers. I can cite several examples where this has come in very handy for me and has made the traveling experience much less painful (it was slow as it were, but would have been twice as slow otherwise). Of course, if superchargers become ubiquitous as I mentioned in my reply to the OP above, this would become a moot point and we wouldn't even need onboard chargers any longer.

The fact that the dual charger option was removed from the design studio due to lack of demand is a matter of fact, not opinion. I believe it dipped below 10% of orders and that's when it was removed. Of course there are some people for whom dual chargers are useful, and some parts of the world where they're still needed, but the rollout of the supercharger network, and even more so the increase in CHAdeMO rapid chargers on the road means that becomes less and less important over time. My bet is that the Model 3 will not have a dual charger option.

MarcG said:
On the second point, 5-minute charging is definitively required when one can't charge at home. Which is the case for many people who live in cities of who don't own their homes. And I would venture to say the majority of people don't want to spend 30-60 minutes stopping to charge every 1.5 to 2.5 hours when doing a long road trip. As early adopters we are willing to do so because we're part of the movement and it feels great, but I highly doubt the vast majority wouldn't see this as an inconvenience relative to the existing gas-fillup model. You'll notice new entrants in the pure EV market (Porsche, Audi) are touting 10- or 15-minute charging for a reason: they want to attract the average buyer, not the early adopters only.

PS: the battery swap station was a half-hearted attempt by Tesla to take a stab at solving the long charging times. They only installed a single station between SF and LA, and they only took appointments by invitation to a subset of CA owners. Declaring this as a failure is not fair because it wasn't a true indicator of whether demand was there for such a model. However I still think the solution is dramatically reduced charging times, not battery swaps, as the latter comes with all sorts of issues such as battery ownership, degradation, etc.

No, super-rapid gas-station-style charging is required when you can't charge in the place where your car sits overnight. If you don't have off-street parking at home but instead park on the street, or in a lot around the corner, then the solution is for those locations to gain slow charging points.

As for the Porsche/Audi rhetoric, well firstly it's just that - talk. What they are actually going to deliver - at best - is 100kW CCS, which will not amount to a 15 minute charge.

I never said superchargers don't need to get faster to go mass market - I just questioned the idea of a 5 minute fill. A car with a 120kWh battery which can be 80% filled in 30 minutes (i.e. 200kW charging) is as much range and charging speed as 99% of people will ever need. Going up from that level to a 1MW charger is a huge waste of money and engineering resource.

Electric cars don't have to be better than ICE cars in every single way in order to succeed. They just have to be better overall. The fact that on the road refilling is slightly slower is balanced against the fact that regular refilling is much faster.

mikeash said:
Seems to me that the solution for the hypothetical future where 100% of cars are electric is not extremely fast charging on the gas station model, but ubiquitous slow (L2) chargers. There's no particular reason that people who park in shared garages or even on the street can't charge overnight, the infrastructure just isn't in place yet. As EVs become more popular, I think that will begin to change.

Exactly.

Quant · Jan 21, 2016

Thanks for all the thoughts and comments above. Good to hear about the liquid cooled supercharger cables. Also, I know about the waste heat issue and also that if a Tesla is parked , say at an airport for a few days or a week, it will lose 5-10% of the charge to maintain onboard regulation and temperature control systems etc. This is specific to EV's and is a important point for me as I spend about 50 PC of my days traveling ( for pleasure) .

1. Perhaps, that and the fact that I no longer live ( and have no plans ) in a single family home , and live in a large state ( Texas ) with just 5-6 superchargers is key.

2. I live in a large upscale, gated apartment complex where there is private personal garage parking for only about 20 PC and only about another 30 PC can have covered parking spots. So, thinking ahead, after the advent of Model 3, IF my apt complex establishes some limited outdoor ( and covered parking ) electrical outlets for charging, it will be limited in number requiring it to be shared. So, in such situations ( about 20 PC of the US population resides in such housing situations ) if charge times can be brought down way down, shared charging may be practicable, else I doubt Model 3 owners will want to wait an hour or multiple hours for charging at their residence, using shared outlets and extensive charge times.

So, I think the talk of an EV world , without solving these types of scenarios, is simply incomplete thinking.

3. I have a couple of MB's ( one that my daughter drives) and usually never keep them beyond say 4 years. So, after 20 odd years, of many MB's ( S, E, GL, GLK class vehicles ) and a few BMW's ( 5 and X5 ), I WANT to move to Tesla. But, lack of EV charging at my residence point, and very limited supercharger network in Tx, Ok, NM, and surrounding states is a big limiting factor.

I think I will reserve 2 Model 3's for sure, BUT! I think I'm gonna have to keep my ICE cars as back up and pay for insurance and maintenance for 2 addl cars! A pretty big waste!

4. People in the above states, will not be able to own Tesla's without backup ICE cars because the supercharger network is in its infancy in these states and going south to LA etc. As, an original NYer, who goes to NYC at least 3-4 times a year, with a mom who lives in a high rise there, again as I walk around, or take the subways, I simply cannot see an EV world for s long time to come, as the charging issues are just not something that will be, or can be, resolved quickly. And, the metro markets in the NE are huge, huge markets for the upscale European car manufacturers.

Elon Musk and team, IMO, need to come up with new and creative solutions for these scenarios, IF, the EV vision is to be realized.

To say, EV charging is ok for 99 PC of people or whatever, or that EV charging with Tesla's are easy etc, from my POV is ludicrous.

I dont want want to be in a Tesla after a 150 mile drive and right arriving back , get a call, saying a relative or family member is in an urgent medical situation or some other urgent required, and be constrained by charging my EV for such an instant emergency, in large states where 100 plus mile drives are very frequent on weekends. I live in Austin and my daughter just graduated and moved to the Dallas area. And, if my residence charging situation is what it is, and there are zero chargers in the Austin metro area, and I or my daughter have to suddenly drive to the other's city on an instant's notice, there is no way I am driving the Tesla with just one single supercharger in between Austin and Dallas. Same applies to Austin- Houston, or Dallas- Houston and other cities in TX, OK, NM, LA etc. So, no way can I just get by having a Tesla, I will still need my MB back up for instant emergencies, even 3-5 years from now. So, that's what's on my mind, as I prepare to reserve 2 Model 3's in March, putting my faith in Elon and team! So, since I also take care of my daughters car needs, I will still need 2 Model 3's and the 2 MB's, which are GLK's. Definitely not an ideal situation or the advent of an EV world for me!

mikeash · Jan 21, 2016

There's no need for private garages or even covered parking for overnight charging. You can charge outdoors and even on the street, as long as there is a charger available. Chargers aren't typically available, but that's just because of low demand. If the tenants wanted it, your apartment complex could install chargers for as many spots as needed to supply all tenant EVs.

For your urgent medical emergency scenario, I don't really see the problem. Austin/Dallas/Houston are pretty well covered with superchargers in between them. You don't need superchargers in the cities, just on the routes between them. If you're worried about getting a sudden call and having to turn around right as you get home, then get enough charge at the supercharger to cover a round trip. It's practical to do this, given the distances involved and the range of the car.

Now, if you head west from Austin, you don't have much. If that's a scenario you need to address, then you're basically stuck right now. But that's nothing to do with charging speeds and everything to do with the supercharger network not having sufficient coverage (yet).

Certainly, the infrastructure needs a great deal of improvement to make EVs ubiquitous. It's all well and good to say that apartments can install chargers for all, but until they do, it doesn't really count. My point is just that just about none of this is about charging speed, but rather charging coverage.

Rocky_H · Jan 21, 2016

@Quant, The apartment situation is going to be a slowly developing thing as a whole over many years. The owners of the properties won’t do anything if no one is asking/pressuring them to. You seem to have your predictions of what your place may do, but have you talked with them? Many apartment and condo residents I have heard from on these forums over the past couple of years have arranged for a charging outlet to get installed at their expense at a parking location, so they can have overnight charging where they live. Ask. Some of this is going to have to be people voting with their feet in the aggregate long term. When people have or want an EV and are looking for an apartment complex, they need to search for and talk with the management of a few where there is some kind of outlet available for charging and choose where to rent based on that. If no one expresses any interest in it and just throws up their hands and say, “It doesn’t exist.”, then it never will exist. This is already the situation with hotels when traveling. Search for or ask hotels about charging before deciding where to stay.

And I guess I just don’t get your saying it won’t work on the Austin-Dallas drive because there is only one Supercharger in between in Waco. It’s there. It makes that drive perfectly workable. You just don’t want to use it? Are you concerned it’s going to be overwhelmed in several years, and your pessimistic idea is that Tesla is never going to build additional capacity on routes that get more full?

GasKilla · Jan 21, 2016

tinm said:
What I would truly love to do is take a baby step with solar at the house.

I work in a home office, so my car is here most of the day. What I have in mind is the minimal amount of solar panels (2? 4?) that would enable me to have say 240V 24A DC (yes, DC) power straight from the panels, straight into the car, like a "baby Supercharger."

I'm thinking of a solar array dedicated to charging the car itself, nothing else, no inverter, no grid-tie, no connection whatsoever to the rest of the house. House would stay on grid power for now. But phase one of the project would be as cheap as possible, with the goal being, charge the car via the sun during the day, period. If car needs more charging at night, charge via grid-powered HPWC. But during day, it pulls straight from solar power with as little in-between the sun and the car as possible.

Is that doable?

Andromeda Power Solar Charger
Andromeda Power Solar Charger | Joshua Tree, CA | Electric Car Charging Station | PlugShare
call that guy, he did that exact thing with a chademo DC fast charger

GasKilla · Jan 21, 2016

Quant said:
Thanks for all the thoughts and comments above. Good to hear about the liquid cooled supercharger cables. Also, I know about the waste heat issue and also that if a Tesla is parked , say at an airport for a few days or a week, it will lose 5-10% of the charge to maintain onboard regulation and temperature control systems etc. This is specific to EV's and is a important point for me as I spend about 50 PC of my days traveling ( for pleasure) .

1. Perhaps, that and the fact that I no longer live ( and have no plans ) in a single family home , and live in a large state ( Texas ) with just 5-6 superchargers is key.

2. I live in a large upscale, gated apartment complex where there is private personal garage parking for only about 20 PC and only about another 30 PC can have covered parking spots. So, thinking ahead, after the advent of Model 3, IF my apt complex establishes some limited outdoor ( and covered parking ) electrical outlets for charging, it will be limited in number requiring it to be shared. So, in such situations ( about 20 PC of the US population resides in such housing situations ) if charge times can be brought down way down, shared charging may be practicable, else I doubt Model 3 owners will want to wait an hour or multiple hours for charging at their residence, using shared outlets and extensive charge times.

So, I think the talk of an EV world , without solving these types of scenarios, is simply incomplete thinking.

3. I have a couple of MB's ( one that my daughter drives) and usually never keep them beyond say 4 years. So, after 20 odd years, of many MB's ( S, E, GL, GLK class vehicles ) and a few BMW's ( 5 and X5 ), I WANT to move to Tesla. But, lack of EV charging at my residence point, and very limited supercharger network in Tx, Ok, NM, and surrounding states is a big limiting factor.

I think I will reserve 2 Model 3's for sure, BUT! I think I'm gonna have to keep my ICE cars as back up and pay for insurance and maintenance for 2 addl cars! A pretty big waste!

4. People in the above states, will not be able to own Tesla's without backup ICE cars because the supercharger network is in its infancy in these states and going south to LA etc. As, an original NYer, who goes to NYC at least 3-4 times a year, with a mom who lives in a high rise there, again as I walk around, or take the subways, I simply cannot see an EV world for s long time to come, as the charging issues are just not something that will be, or can be, resolved quickly. And, the metro markets in the NE are huge, huge markets for the upscale European car manufacturers.

Elon Musk and team, IMO, need to come up with new and creative solutions for these scenarios, IF, the EV vision is to be realized.

To say, EV charging is ok for 99 PC of people or whatever, or that EV charging with Tesla's are easy etc, from my POV is ludicrous.

I dont want want to be in a Tesla after a 150 mile drive and right arriving back , get a call, saying a relative or family member is in an urgent medical situation or some other urgent required, and be constrained by charging my EV for such an instant emergency, in large states where 100 plus mile drives are very frequent on weekends. I live in Austin and my daughter just graduated and moved to the Dallas area. And, if my residence charging situation is what it is, and there are zero chargers in the Austin metro area, and I or my daughter have to suddenly drive to the other's city on an instant's notice, there is no way I am driving the Tesla with just one single supercharger in between Austin and Dallas. Same applies to Austin- Houston, or Dallas- Houston and other cities in TX, OK, NM, LA etc. So, no way can I just get by having a Tesla, I will still need my MB back up for instant emergencies, even 3-5 years from now. So, that's what's on my mind, as I prepare to reserve 2 Model 3's in March, putting my faith in Elon and team! So, since I also take care of my daughters car needs, I will still need 2 Model 3's and the 2 MB's, which are GLK's. Definitely not an ideal situation or the advent of an EV world for me!

Have you looked at Supercharger | Tesla Motors ? According to the (sometimes optimistic) map by the end of this year 100% of the major highways in TX will be covered. Today you can drive from Austin to DFW, San Antonio, Houston, Corpus Christi, New Orleans, Oklahoma City, and either coast. I think you are just imposing limits on yourself. I know TX isn't as progressive as CA but Ausitn is a fairly liberal town so I'm sure if you offered to pay for the installation of a charger (or NEMA 14-50 outlet) and a small fee for electricity in your apartment building, the owner would likely go for the deal. And if the owner said no then you could appeal to the city or move to a place that will accommodate your needs. Just go for it, you'll be glad you did.

Also of great use supercharge.info and PlugShare - EV Charging Station Map - Find a place to charge your car!

Quant · Jan 21, 2016

mikeash said:
There's no need for private garages or even covered parking for overnight charging. You can charge outdoors and even on the street, as long as there is a charger available. Chargers aren't typically available, but that's just because of low demand. If the tenants wanted it, your apartment complex could install chargers for as many spots as needed to supply all tenant EVs.

For your urgent medical emergency scenario, I don't really see the problem. Austin/Dallas/Houston are pretty well covered with superchargers in between them. You don't need superchargers in the cities, just on the routes between them. If you're worried about getting a sudden call and having to turn around right as you get home, then get enough charge at the supercharger to cover a round trip. It's practical to do this, given the distances involved and the range of the car.

Now, if you head west from Austin, you don't have much. If that's a scenario you need to address, then you're basically stuck right now. But that's nothing to do with charging speeds and everything to do with the supercharger network not having sufficient coverage (yet).

Certainly, the infrastructure needs a great deal of improvement to make EVs ubiquitous. It's all well and good to say that apartments can install chargers for all, but until they do, it doesn't really count. My point is just that just about none of this is about charging speed, but rather charging coverage.

Thanks, MikeAsh and Rocky H. Yeah, I knew that you could have chargers outdoor etc. And, yeah if I am driving for an emergency, I certainly don't wanna get stuck enroute, with only 1 supercharger location ( with say 4 spots ), if I have to wait in line for others. Ans, yes, I may drive to Santa FE, Taos, NM , New Orleans, or maybe even OK or up towards OK/ TX border. The supercharger situation here is quite limited....not like CA!!!

yeah, I'll have to speak with the apt Mgmt and they are a multi- state Corp , so I think I'll be able to. But, I would prefer they install, because I don't want the liability under Any scenario, however unlikely. And, I'd be happy to pay say additionally for that and the electric, monthly. But again, they know I'm only there 50 PC of the time.

I don't think I am by any means unique, about 20 million Americans reside in non single family homes.

So, I have decided that I will need to keep my ICE MB's as back up, until maybe 2020-2022, when the situation is more of a norm, rather than a big exception and the supercharger network and others offering charging is more prevalent and speedier. That's why the The reason for my question , originally, therefore was speed in the future. When home or residence charging has to be shared.

For now, I am resigned to keeping the ICE MB's as backup. But, that's maybe for the next 5 years, max, I expect.

- - - Updated - - -

GasKilla said:
Have you looked at Supercharger | Tesla Motors ? According to the (sometimes optimistic) map by the end of this year 100% of the major highways in TX will be covered. Today you can drive from Austin to DFW, San Antonio, Houston, Corpus Christi, New Orleans, Oklahoma City, and either coast. I think you are just imposing limits on yourself. I know TX isn't as progressive as CA but Ausitn is a fairly liberal town so I'm sure if you offered to pay for the installation of a charger (or NEMA 14-50 outlet) and a small fee for electricity in your apartment building, the owner would likely go for the deal. And if the owner said no then you could appeal to the city or move to a place that will accommodate your needs. Just go for it, you'll be glad you did.

Also of great use supercharge.info and PlugShare - EV Charging Station Map - Find a place to charge your car!

Thanks, I think you are right on all the above points. And, yes, I will talk to the apt folks in 2017 ( a few months before the Model 3's are actually delivered ) but I was trying to understand the future of charging tech and theoretical Limits for speed ....but right now, Tesla is only focused on say about 15 states, IMO. By, 2020 they will need to focus on at least 45 states and also on those not in single family homes.....that is still a strategic question that the EV industry and Elon Musk need to creatively address. I think cities like Austin will need at least 5 supercharger locations. I think Tesla should include highway supercharger locations for free ( or included in original purchase ) and allow people to pick city locations' superchargers for additionsl monthly or annual fee, say $30 / month or $250 a year, paid upfront. I think that would be reasonable, would solve many questions, make women more comfortable ( re range anxiety... Thinking as an investor now ) and produce revenue streams to keep moving the charging complex forward so that in say 10 years, it is ubiquitous and strategic diffrerntial advantage for Tesla.

Could home charging one day be quicker?

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