aesculus
Still Trying to Figure This All Out
Did anyone who attended the recent events ask about the new HPWC rumor that has been going around recently?
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To 72 A or not to 72 A?
- Thread starter investmentgamer
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Mark Z
Active Member
I would agree as the heat generated in the wiring is far less at 40 amps than at 72 or 80.
The one time my HPWC became non-operational was after a 80 amp session. The fuses were okay. The HPWC needed replacement and Tesla Motors handled that under warranty.
aesculus
Still Trying to Figure This All Out
Not much to say yet. Someone over on the Tesla forums claimed that a Tesla employee said they were coming up with a new external charger for the MX that would negate the need for an internal 72 amp charger and that's why they only had the 48 amp one. That would imply some form of at home DC charging but to date there has been no follow on info, just a wild rumor.
I can't imagine there being rumors about this vehicle. I mean, I can't wait to get mine so that the second row seats swivel outward and present themselves to me. Not to mention the electrochromic windshield. It's going to be great!
That doesn't make any sense. A DC charger would be much more expensive than the 72A upgrade option, and being at home it wouldn't solve the problem of needing a higher amp charging when traveling. That's the more common reason for 72A charger in a Model X or dual chargers in a Model S, not needing faster charging at home.
MrBoylan
Member
Ouch. Rub it in, why don't you? At least you didn't mention that those gorgeous swiveling, rotating seats also folded flat and that the heating elements in the Falcon Wing Doors would melt off the snow and ice so you'd never have to clear them off by hand.
Can I go back in time to when the X was still perfect?
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...Unless those will also be the new chargers for the destination charging program, too?
If PowerWall 2 is higher capacity, couldn't you effectively DC charge a vehicle using the Powerwall battery as a buffer? The PowerWall would have to be full or close to it when you start, and it would dump DC to the car while AC charges the Powerwall back up (or stops it from discharging too quickly). For this to be feasible though, I'm thinking that the PowerWall would need to have at least half the capacity of the battery it's charging. And a 45kWH battery would be way too expensive. Plus I have no idea if a battery could simultaneously be charging and discharging so... never mind.
pvogel
Member
I do very much like the idea of a "supercharger lite" as a destination charger. 2-4 72A chargers ganged together (instead of the 10 used in a supercharger) to deliver 35-70kW would make for a very nice destination charge or even 1 hour restaurant stop bridge to the next supercharger on a road trip. Not sure the typical destination/restaurant would have the grid service needed for it, but maybe...
As for the PowerWall, 7kW daily cycle power wall falls far short of what would be needed. Getting to a 49kW power wall would take 7 powerWall units in parallel, that's a huge chunk of house wall real-estate and would probably be considered an eyesore. You wouldn't necessarily need to charge and discharge at the same time. The idea here would be you've "precharged" half your Tesla into a stationary battery that can be dumped very fast into your Tesla when needed, then recharge it slowly over time at your house. You'd essentially gain 1/2 the range of your car in about 10 minutes which could be done 1-2 times a day.
Peter+
I went with the 72A as I figured it would be worth it - even if I only need it once, I will be grateful. I also think as other chargers are built out, higher amperage charging will be more prevalent. ChargePoint, for example, is now offering higher amp options.
When I've mentioned the PowerWall idea before, my intent wasn't that you'd be able to "Supercharge" from one. It was that the PowerWall already is inverting to DC. I don't know the input rate on the PowerWall, but the way I view it, you would bypass the onboard charger and be likely to charge at a faster rate, using the PowerWall's mechanism, than you would with the onboard charger. I could be wrong about that, but I never imagined that you'd have to have enough storage to dump directly into your vehicle - that wouldn't work for most people. That said, I plan to put 7 PowerWalls in parallel.
I'm not so sure "there was no real choice" ...
I installed an 80 amp Clipper Creek CS 100 at my summer home a few months after I purchased my Chevy Volt in 2012. When I upgraded to a Model S 85D this past summer, I did not add the dual chargers to my Model S mostly b/c it was not an option in the design studio (I wonder if there is an easter egg of sorts in the Model S order page where the dual chargers can be added.)
If it were an option, I most likely w would have added it during the config, but after 7 months of driving around in my Model S and 9,000 miles (I just returned from a road trip from NYC to Southwest Florida) I can say I do not really need the second charger, although it is nice to have.
In my opinion DC charging is the future -- even a slower ChAdeMo. Most people will not need 200 miles "in the tank" every morning. For road trips, 20 kW or 50-60/hr, is certainly faster than 25-30 miles gained in an hour from the standard charger, but won't get you very far on a road trip with an extra 60 miles. Even a slow ChAdeMo will get you between 120 and 150 miles per hour (in contrast to a supercharger's ~300 miles per hour,) but again Level 3 charging is in a completely different ball park. BTW sorry if these miles per hr gained figures I am using are for the Model S and do not match up exactly with what you get for the Model X. I note that the standard onboard charger of the Model X is capable of pulling 48 amps, in contrast to 40 amps for the Model S single charger. Not sure how much of a difference it makes in the miles per hr gained between the 2 vehicles.
if you do need 200 miles in the tank every morning for a commute then yes I would get the 72 amp charger so you can take advantage of a HPWC at home or at work. Also remember that in public places the HPWC are fed by 3-phase power which reduce the Volts from 240 to 208 (and sometimes will only provide 200 V, which further reduces the charging rate.)
as an aside, it is a personal pet peeve of mine that a HPWC set up to provide 80 amps continuous service, will top out at 40 amps when fed with 208 V 3-phase power. if the onboard charger is capable of receiving 9600 watts and is only getting 208 V power, it should be pulling 46 amps from a 100 amp line, but for some reason, it is limited to 40 amps, which is the max the Model S single charger can pull from a 240 V line. I do wonder if the standard onboard charger of the Model X, capable of pulling 48 amps, would pull more that from a 3-phase 208 V line, tho I suspect not.
Also, in my case, the destination charger HPWC where I do most of my charging is limited to 40 amps, so the second on board charger is useless. At my summer home, I installed an 80 amp charger (actually I think my clipper creek is set up to max at 74 amps) but I find that I do not need that much extra range, and can get plenty with an overnight charge at 40 amps. Remember that in the wild you will find many more destination chargers that only provide 40 amps, and not 80 -- so the 72 amp charger of the Model S won't help you.
This is because wire sizes are current-limited. It takes the same size wire to deliver 80A, whether at 12V or 120V or 208V or 240V. While Tesla calls their charger a "10 kW" charger, it's actually a "40A charger" (and for even more technical fun, it's actually a 48A/11kW charger when used in a balanced three-phase configuration, but only 40A in single-phase to protect the neutral).
That's why you're limited to 8.3 kW if fed with 208V.
Thank you for this info. it makes perfect sense actually.
I do wish they could set up the onboard chargers to pull from a balanced 3-phase configuration the way they do in Europe. I would say 3/4 destination chargers I have used in the wild are 3-phase 208 V configs. how amazing would it be to be able to pull 208 V x 48 Amps or 9,984 W at a time... maybe someday.
MichealW
Member
People have fought me hard on this but here it goes again... I decided to triple check.
So I took the test drive here in Los Angeles at the Burbank location. I bumped into the head engineer (there were several there and I specifically asked for the one with the most knowledge) and I asked him the question... "Is the 72amp in the Model X upgradable with software only?" He said, "We now know that the Model X unlike the S has only one Junction box that goes in the back of the car (In the side back panel not under the back seat with two boxes like the Model S) that houses all it needs for the upgrade. Software only? I said, he then said "Its looking like that yes". These are his exact words.
So as I've been saying all along (I have now checked with two head engineers) its software and easily upgradable on the X. The cost has not been determined yet but I've been told that $1200 is a good guess.
So I took the test drive here in Los Angeles at the Burbank location. I bumped into the head engineer (there were several there and I specifically asked for the one with the most knowledge) and I asked him the question... "Is the 72amp in the Model X upgradable with software only?" He said, "We now know that the Model X unlike the S has only one Junction box that goes in the back of the car (In the side back panel not under the back seat with two boxes like the Model S) that houses all it needs for the upgrade. Software only? I said, he then said "Its looking like that yes". These are his exact words.
So as I've been saying all along (I have now checked with two head engineers) its software and easily upgradable on the X. The cost has not been determined yet but I've been told that $1200 is a good guess.
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Not saying you're wrong, but I don't understand why it can't be two separate single chargers - a 48A and a 72A which each connect through a single junction box. We knew all along there wasn't a "double charger option". Interesting regardless.
MichealW
Member
I believe you are correct. A 48A and a 72A through a single junction box. Nothing to add. Upgradeable through software.
pvogel
Member
Given that the vast majority of engineering goes on in Fremont and Palo Alto, and the engineers at the Fremont plant say you can't upgrade to 72A after build, why do you continue to spread this potentially disastrous rumor? If people need 72A charging to make destination charging practical for them and trust you that they can add it later (despite all official word from Tesla being to the contrary) they are going to be screwed.
If YOU want to depend on a later software upgrade to 72A charging, go ahead, and when you have proof that your 48A charger could be SW upgraded to a functioning 72A charger, please post!
I find it extremely unlikely that 72A charging would be software upgradeable. That would mean that Tesla is unnecessarily using high-amperage hardware in every Model X sold just to make it easier to do the "upgrade" in software. It doesn't make sense that they would do that when their official line is that it's not upgradeable at all. I consider it more likely that an employee stating this just doesn't know what they're talking about.
MichealW
Member
Wow... Disastrous? There are a few things in this world that I reserve for the word DISASTROUS... This being far from it. I am only repeating what I have heard from top engineers and feel its something people may be interested in. Should I just keep it quiet? I personally would want to know this information. I am pretty sure this is what this forum was created for. You need a reality check bud. This is a CAR. Yes, a special one but lets leave the word disastrous for things that really earn the meaning.
I will continue to be honest about any thing I find out that could be helpful to people... I certainly won't stop you or others from doing the same regardless of rather I disagree or not.
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