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So I know a supercharger allows me to draw up to 170kW for my M3 RWD, but I'm confused about the kW my 240v L2 mobile charger (TMC) draws at 24A.
How do I figure that out?
Wall Connector Technical Details | Charge Speed Max Miles of Range per Hour of Charge* | |||||
---|---|---|---|---|---|---|
Circuit breaker (amps) | Maximum output (amps) | Power at 240 volts (kilowatt) | Model S (mph) | Model 3† (mph) | Model X (mph) | Model Y† (mph) |
60 | 48 | 11.5 kW | 41 | 44 | 35 | 44 |
50 | 40 | 9.6 kW | 34 | 37 | 29 | 37 |
40 | 32 | 7.7 kW | 27 | 30 | 23 | 30 |
30 | 24 | 5.7 kW | 21 | 22 | 17 | 22 |
20 | 16 | 3.8 kW | 14 | 15 | 12 | 15 |
15 | 12 | 2.8 kW | 10 | 11 | 9 | 11 |
Note the † in the Model 3 and Model Y columns. The footnote that accompanies that table says: "Maximum charge rate for Model 3 Rear-Wheel Drive and Model Y Rear-Wheel Drive is 32A (7.7kW) - up to 30 miles of range per hour."
Circuit breaker (amps) Maximum output (amps) Power at 240 volts (kilowatt) Model S (mph) Model 3† (mph) Model X (mph) Model Y† (mph) 60 48 11.5 kW 41 44 35 44 50 40 9.6 kW 34 37 29 37 40 32 7.7 kW 27 30 23 30 30 24 5.7 kW 21 22 17 22 20 16 3.8 kW 14 15 12 15 15 12 2.8 kW 10 11 9 11
Hokay. Let's get this clear: A Tesla has two ways of getting energy into the battery:So I know a supercharger allows me to draw up to 170kW for my M3 RWD, but I'm confused about the kW my 240v L2 mobile charger (TMC) draws at 24A.
How do I figure that out?
Each plug adapter for a Tesla Mobile Connector is $35 or $45, according to https://shop.tesla.com/product/gen-2-nema-adapters . The Mobile Connector is $250 and includes the 5-15 and 14-50 plug adapters, according to https://shop.tesla.com/product/mobile-connector .And then, there's the plethora of 240 VAC sockets: NEMA14-20, NEMA14-30, our favorite NEMA15-50, and so on. Tesla will happily sell you adapters for those and others of the 240VAC flavor for about $15 a pop; the Mobile Connector is about $220, I think, and it comes with a NEMA5-15.
The loss is closer to 10%.There's a percent or so loss of energy going through the rectifiers. But, on my LR cars in the garage, I actually do see 46 miles of charge per hour when they're charging on a TWC hooked to a 60A breaker.
That’s master class material sir!Hokay. Let's get this clear: A Tesla has two ways of getting energy into the battery:
Let's get the Supercharging out of the way. I happen to have had nothing but Tesla Long Range cars with 85 kW-hr batteries or some such. When those batteries are near dead empty (like, less than 20% or so), they can be charged at up to 250 kW; that's between the car and what the Supercharger is capable of. Once one gets above 20% state of charge or so, the car slows down the charging rate to keep from damaging the batteries. By the time one is at 80% SOC, the charge rate is down around 30-40 kW or so. The last 10% takes about as long as the first 90%. In any case, any Tesla hooked up to a Supercharger typically goes from 0% SOC to 80% SOC in a half-hour or less. And that's Standard Range cars with a smaller battery as well as the Long Range cars with bigger ones.
- Using the Mobile Connector, connect some species of AC power (in the North American market, this is single phase 120 VAC or 240 VAC). This gets rectified by (up to) three 16A capability rectifiers to a DC voltage, which is then used to charge the battery in the car.
- Connect a Supercharger to the car. A Supercharger is, essentially, a variable DC power supply. It goes, pretty much, directly to the battery, bypassing any and all rectifiers.
Supercharging is often defined as "Level 3" charging.
So, It Is Defined that if one connects 120 VAC to a Tesla, typically using the car's mobile connector or Something Else Similar, then that's defined as Level 1 Charging.
Similarly, if one connects 240 VAC to a Tesla, then that's defined as Level 2. But Level 2 actually covers a bit of ground, as follows:
The reason that #2 is even talked about is that when one goes to a Level 2 charger in a parking lot.. well, I've never seen one of those that wasn't 208 VAC.
- Most North American homes receive something called "Split Phase". Three wires cometh down from the power pole. One wire is Neutral; a second wire is a Hot, let's call it Hot #1, and is 120 VAC with respect to Neutral, as measured with an AC voltmeter. The third wire is also a Hot, let's call it Hot #2. This wire is also 120 VAC with respect to the neutral. But, if one hauls out an oscilloscope and looks at the actual waveforms of Hot #1 and Hot #2 with respect to Neutral, one will discover an Interesting Thing: When the sine wave that is Hot #1 is going Up, the sine wave that is Hot #2 is going down, and vice versa. If one connects a voltmeter from Hot #1 to Hot #2, instead of getting 120 VAC or something, one gets 240 VAC.
- On the other hand, most business in the US don't get split phase. For various reasons, mostly to do with motors, they get 120 VAC three phase. Yep, there's a neutral, like in split. But the three phases (let's call them A, B, and C) are each 120 VAC to Neutral, but instead of being opposite of each other, they're 120 degrees (as in, say, circles and sine waves) from each other. A voltmeter connected between any of the A, B, C and Neutral gets one 120 VAC; but that same voltmeter connected between A and B, A and C, or B and C will net you 208 VAC.
So: How much power? Pretty much, it's the current of the socket in question times the circuit voltage.
Additional snivvy: In the North American market, following the National Electric Code, the maximum amount of heavy current one can put on a circuit is 80% of that circuit's rating. "Heavy Current" is definitely what a Tesla draws when it's charging.
So, starting with L1. A standard 120 VAC socket with two parallel blades is a 15A. In fact, time for my favorite graphic, straight from Wikipedia:
View attachment 1055373
The typical home socket is a NEMA5-15 and has a 15A breaker on it. Maximum power is 15A*80%*120VAC = 1440W.
Modern construction often calls for, in the garage, a 20A circuit and socket. You can tell a 20A socket because one of the two parallel openings in the socket can accept a right-angle blade. Maximum power is 20*80%*120VAC = 1920W.
And then, there's the plethora of 240 VAC sockets: NEMA14-20, NEMA14-30, our favorite NEMA15-50, and so on. Tesla will happily sell you adapters for those and others of the 240VAC flavor for about $15 a pop; the Mobile Connector is about $220, I think, and it comes with a NEMA5-15.
Now comes the fun. If you have a Long Range or Performance version of a Tesla, they come, built in, with three (3) 16A AC to DC rectifiers. With all three running, it's possible to charge the car at 48A. At this time, this requires a Tesla Wall Connector (or equivalent) that can be hardwired to a 60A breaker (using 60A capable wire) in a breaker panel. 80% of 60A is 48A; 240 VAC * 48A = 11.52 kW.
If you have a Standard Range Tesla (indication: advertised mileage is less than 300 miles), it comes with but two (2) of those rectifiers. So the maximum current that can be drawn is 32A.
So, working one's way up from the bottom:
NEMA14-20: Capable of 20A, max. 80% of that is 16A. 16A * 240 VAC = 3.84 kW. That's still a lot more than any L1 circuit one can find.
NEMA14-30: Capable of 30A, max. 80% of that is 24A. 24A * 240 VAC = 5.76 kW.
NEMA14-50: Interesting. Nominally would be able to do 40A, but it turns out that's a bad assumption. You may have noticed in the chart above that there's 15A sockets, 20A sockets, 30A sockets, 50A sockets, but there's no 40A sockets. But, as it happens, there are 40A loads, like electric clothes driers and electric stoves. 50A wire.. costs a lot, copper's expensive. So the NEC has made an exception: If one has a 40A load, one can put in a 40A breaker, 40A wire, and a NEMA14-50 socket. One is supposed to put a label on that socket. Yeah, and you tell me: 20 years after that socket's been installed, any bets as to whether that label is still there? So, if one plugged a Tesla into such a thing, and the Tesla drew 40A on a heavy load basis, one would run the significant danger of Catching The House On Fire. (Not joking). Since a Tesla can't tell whether it's a real 50A circuit or a 40A circuit out there, this is thought to be the reason that a Tesla Mobile Connector maxes out at 32A. So, a TMC plugged into a NEMA14-50 gets you 32A, not 40A. Power is 32A * 240 VAC = 7.68 kW.
As a previous poster put up, Tesla has a "Miles of Charge Per Hour" chart that's different for different cars. But how they got it is pretty straightforward: Go to the Mulroney sticker on the car and find the W-hr/mile rating for the car. A Model 3, for example, is around 250 W-hr/mile.
So: Say one has a 30A circuit. That's 5.76 kW. 5.76 kW/(250 W-hr/mile) = 23 miles/hour.
A NEMA5-15, 120 VAC 15A circuit, is 1440W. So, that'd be 1440W/(250 W-hr/mile) = 5.76 miles/hour.
Now, if you have a Standard Range Tesla, the most current it can accept is 32A @ 240 VAC. That's 7.68 kW, so it's 7.68kW/(250 W-hr/mile) = 30.7 miles per hour.
If you have a Long Range Tesla Model 3, you can get 11.52 kW. And that will get you 11.52kW/(250 W-hr/mile) = 46 miles of charge per hour.
There's a percent or so loss of energy going through the rectifiers. But, on my LR cars in the garage, I actually do see 46 miles of charge per hour when they're charging on a TWC hooked to a 60A breaker.
Finally: Note that all my 240 VAC numbers above were based upon, well, 240 VAC. If one is at a Chargepoint or some other public L2 charger, it's not going to be 240 VAC, it'll be 208 VAC. It's pretty common to find 32A, 208 VAC public chargers: Those have a wattage of 32*208 = 6.66 kW, and, for a M3, a charge rate of 6.66 kW/250 W-hr/mile) = 26.6 miles of charge per hour. Using the inevitable J1772 adapter that came with your car.
So that's almost 30x the amount of kWs I can stuff into my car using a supercharger! And can I assume that equates to 30x the speed at which I can charge
The bottom line for me is that while my RWD M3 apparently tops out at 5.7kW (@24A, of course) with my TMC at home, a supercharger can deliver up to 170kW to my base M3.
So that's almost 30x the amount of kWs I can stuff into my car using a supercharger! And can I assume that equates to 30x the speed at which I can charge (?)
I get 24 mph at home, so I presume (under perfect conditions) I could get as much as 720 mph at a supercharger (30x24) !?!? Since my car maxes out at about 270 miles of range at 100%, I should be able to go from 0-100% in a half hour at a supercharger, right? (except for the inevitable throttle-down of rate-of-charge.) I have seen where Youtuber Out of Spec got a full 0-100% charge in a M3 in about 50 minutes.
You can tell I haven't used a supercharger but once.
Hokay. There's a few interesting tidbits here.The bottom line for me is that while my RWD M3 apparently tops out at 5.7kW (@24A, of course) with my TMC at home, a supercharger can deliver up to 170kW to my base M3.
So that's almost 30x the amount of kWs I can stuff into my car using a supercharger! And can I assume that equates to 30x the speed at which I can charge (?)
I get 24 mph at home, so I presume (under perfect conditions) I could get as much as 720 mph at a supercharger (30x24) !?!? Since my car maxes out at about 270 miles of range at 100%, I should be able to go from 0-100% in a half hour at a supercharger, right? (except for the inevitable throttle-down of rate-of-charge.) I have seen where Youtuber Out of Spec got a full 0-100% charge in a M3 in about 50 minutes.
You can tell I haven't used a supercharger but once.
I'm not sure where @ATPMSD got his "200 kW" plot from; the modern L3 Superchargers can run up to 250 kW. But there are definitely 120 kW and 150 kW systems out there.
As long as it's a modern (<3 year old) car. Those of us who own (or owned) old 85kWh S's will disagree with the second sentence...The general rule of thumb is solid, though: Show up at a Supercharger with, say, 5% left, and the time to charge to 80% is 30 minutes or less. And it doesn't matter, generally, what kind of Tesla one has, Long Range or Standard Range.
The bottom line for me is that while my RWD M3 apparently tops out at 5.7kW (@24A, of course) with my TMC at home, a supercharger can deliver up to 170kW to my base M3.
So that's almost 30x the amount of kWs I can stuff into my car using a supercharger! And can I assume that equates to 30x the speed at which I can charge (?)
I get 24 mph at home, so I presume (under perfect conditions) I could get as much as 720 mph at a supercharger (30x24) !?!? Since my car maxes out at about 270 miles of range at 100%, I should be able to go from 0-100% in a half hour at a supercharger, right? (except for the inevitable throttle-down of rate-of-charge.) I have seen where Youtuber Out of Spec got a full 0-100% charge in a M3 in about 50 minutes.
You can tell I haven't used a supercharger but once.