Yes, but the likelihood of 4 similarly charge depleted cars plugging in at the same time with similarly warmed batteries is about 0%.
All on one cabinet? 4 stalls immediately adjacent? All at the same time? Really? That is extremely likely? Hmm, I guess I have been extremely unlucky to have never ever seen this if it is so common.
Which size cable is that?The 575 kW isn't just battery storage, it is the shared DC bus. So the input is 350kW from AC and 575kW from the shared DC bus. (Which can be other V3 cabinets and/or battery storage.)
No, it isn't enough. As that would mean you can't even have 2 cars plug in to the same cabinet at once and get close to the 250kW.
Maybe you should go back and watch some of the videos from the V3 launch where Tesla timed to have everyone plug in at the same time with precondition vehicles.
I don't care to read all that, but here is an example of a 2 cabinet site for you to examine and correct any misunderstandings you may have about how superchargers work.
The DC bus is very high voltage (~900V), so reduces the need for bulky wiring. (As shown in one of the subsequent posts here).All on one cabinet? 4 stalls immediately adjacent? All at the same time? Really? That is extremely likely? Hmm, I guess I have been extremely unlucky to have never ever seen this if it is so common.
If the bus is shared as you suggest means every single component in the cabinet on the incoming side has to be capable of 1mw of power. That’s 1200A at 480V. Derate 80% for charging and you need 1500A input capability per cabinet (and what are they doing with a 1600A breaker for 12 stalls? Shouldn’t it be 4500A?).
View attachment 848669
2000 kcmil cable is 1.4-1.6 INCHES in diameter. 3 phase power requires 4 wires. 6 inch conduit can only hold 3 2000 kcmil cables. Maybe the ground is small enough to also pass through.
500 kcmil is $30/ft, 1000 kcmil is $90/ft, couldn’t find pricing on 2000 kcmil but at least $180/ft, maybe as much as $270/ft x 3 wires so $800/ft x # cabinets. At $100k valuation for 8 stalls, that’s 125 ft of wire max and that leaves no money to pay workers or for anything else needed on the electrical side. WAIT! 2000 kcmil is only 750A so you’d need 2 runs for every cabinet. $1600/ft and only 62ft max cable per 8 stall site.
All of the full power sharing sounds great until you factor reality. Just like 4680. Just because someone said the DC bus is shared doesn’t mean it works that each cabinet can output 250kw x 4 stalls. Just because Tesla says it’s a 1mw cabinet, doesn’t mean it actually outputs that. The cabinet is limited by code and design based on internal wiring as to how much it can accept and output. And the on site transformer. As stated above, that is 430A or 360kw (which lines up nicely with the 430 max ampacity at 90C for 500 kcmil cable). This is more than the combined output of 300kw of 2 V2 cabinets but not much more. The sharing is better, you aren’t immediately cut to 75kw when someone plugs in next to you but it is still not capable of delivering 4x 250kw from the same cabinet.
If you would like to prove this wrong, please document (with video) 4 cars plugging in to 4 stalls from the same cabinet on an entirely empty V3 site (it’ll allow for full power sharing as you suggest) and getting over 360kw combined output at any time. You need 1290A of 480V 3 phase power to output 1mw. So your chosen V3 site better be at least 12 stalls or there won’t be enough power.
From Wikipedia:
“A 1 MW charge box supplies 4 stalls at up to 250 kW each,[38][39] and can have a 575 kW battery storage. However the grid input is limited to around 350 kW.”
350kw in and 1000kw out? Now THAT would be amazing synergy right there.
@pdx_m3s I wasn’t implying it was. Just pointing out what people like pb thinks is likely isn’t possible whether it happens or not and if it was so likely, why wouldn’t Tesla have designed the system to handle that? Right, because it doesn’t happen. 360kw across 4 stalls is plenty since 4 cars never arrive to the same cabinet at once.
There’s definitely wires between the power cabinets. They are often spaced far apart from each other.
I think you exaggerate how often cars plug in at the same time and the exact same state of charge to the same cabinet. Do you know for a fact that everyone who arrives at a SC arrives at less than 20% with a preconditioned battery? No, they don't. Stop saying this scenario is highly likely.
Thank you for providing that. Honest question, does the NEC ampacity rating change when voltages are higher or DC vs AC? My understanding is cables are rated to a certain voltage (1000V in this case( and within that voltage there is a set max ampacity. For the cable in the drawing you provided, 350 kcmil RWU90 AL, allowable ampacity in open air is 445, in conduit is 280 (not including any deratings for continuous use). The drawings show 480V at 465A AC and 350-631A DC at 0-500V DC. It doesn't seem like this cable can be used for this setup without some throttling somewhere in the system. Can anyone here explain this? I can't run 6ga romex (55A) for a 60A charging circuit, how can 280A cable be used for 350-631A service? The notes say 2 runs to each post so is this split so a total of 560A available? Get us closer but still seems on the low end.
Yes, but not really. It is only 2x the voltage of the AC side at similar amps so same wire size. Amps determine wire size. More voltage means more KW on the same wire size but that becomes a difference at a much higher scale when it relates to wire size.
It really depends on the location of the supercharger. Chargers in urban areas probably have a lot of opportunity charging at high SoC, so may only be drawing 35-70kW. Once you get on the highway though, lots of people don't charge past 70% unless they have to and the NAV optimizes very similarly.
On the shared DC bus you can see the 400A fuse designation, as this is only a 2 cabinet site. The runs to the posts are 631A peak, 350A continuous, so with 2 runs (560A continuous) that's fine, as the pack voltage rises quickly and charge taper takes over shortly thereafter.
The cabinet is rated for 350kW on the A/C side, but as mentioned can pull an additional 575kW off the shared DC bus (just shy of 1MW total). Each charge post has it's own DC/DC converter (every vehicle pack is going to be at a different voltage at any given moment), so technically if you connected 3 cabinets together, but only 1 had stalls, every vehicle could get 250kW simultaneously. I actually wonder if the long term plan is to add additional cabinets that have no stalls and just feed 4 other cabinets for additional capacity on the shared DC bus.
Possible but don’t really see Tesla doing this. I think they’ll focus on quantity of SC stalls rather than adding additional power to the existing stalls.
How can I be exaggerating? I have never said how often it will happen. Only that it can happen and that it will be much more likely as more fast charging EVs hit the road.
Onky if all those brands use Superchargers which they can’t now so your statement doesn’t hold water. And you said extremely likely. That implies it happens almost all the time. Like, go to a fairly busy supercharger and it happens once a day or every other day. That would be considered extremely likely. Once a month, that would be unlikely.
You're arguing with multiple people; I said that right after you stated there was a 0% chance of it ever happening. The very existence of the shared DC bus is proof that Tesla engineers expected it to happen and you never experiencing slow charging at a v3 station probably means it's working.
