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This is what they told me:Ashley posted:Thanks so much for reaching out to us with your inquiry about Plugless. The Plugless system for Tesla Model S is a true 7.2kW charger and will charge your Tesla at the same rate as a corded charger that plugs into your EV. In order to do this it does require a bit more electricity in order to transfer the electricity over the 4” air gap between the parking pad and your vehicle. It is about 12% more electricity that you are currently using with a corded charger since the Plugless system is about 88% efficient.
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Oct 14, 2016 01:58
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So that means there's a ~1kw loss. That's probably all heat loss, which might be a problem for people living in places where temperatures degrade batteries - a 1kw heater right under the battery pack might add some heat control issues. Nice for those of us that live in the frozen north, though.
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Oct 14, 2016 12:04
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Is it under the battery pack? I thought it was under the frunk, so it could bake the groceries you forgot were in there. E: even if it is under the pack, it would be under only a small portion of it, and behind the shield I think. Subjunctive fucked around with this message at 13:47 on Oct 14, 2016 |
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Oct 14, 2016 13:44
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Subjunctive posted:Plugless does L2/7.8kW, which is what most people get anyway, right? Tesla model S's will charge at up to 240v/40a with just the portable cable, which is 9.6kw. The wall connector allows up to 48a, which is 11.5kw, or 72a with the high-amperage charger option, which is 17.3kw. Legacy dual-charger Model S's will charge just a smidge faster, though I can't find numbers. (Tesla's website is loving awful for actual numbers. They give you charge numbers based on breaker capacity, rather than actual continuous draw, and like to express charge rates in miles of range per hour, instead of actual numbers. I hate car companies.) (Not sure if Roadsters will do the same.) It appears that the Plugless system assumes a 40a breaker, and is designed for 32a continuous. (32a continuous is the aforementioned 7.6kw.)
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Oct 14, 2016 13:58
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Elephanthead posted:Why can't a robotic arm just plug in my car? Tesla has actually experimented with that: https://www.youtube.com/watch?v=uMM0lRfX6YI
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Oct 14, 2016 16:26
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Yeah the robotics answer is far simpler. Machine learning + a basic camera + slight range of motion on the charger "arm" would be all you need. There could be a literal and/or figurative bullseye underneath the car that the arm hooks into. Make it plug in once a car drives over it and turned off. Make it plug out once the car is turned on. That entire system is honestly not THAT complicated and will have monumentally less technological hurdles to jump.
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Oct 14, 2016 18:24
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It just seems like 12% loss is a good amount when you start talking about hundreds of thousands of cars on the road. It's one thing for a cellphone that uses a tiny fraction of the power, but it just seems wasteful at a fleet level.
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Oct 14, 2016 18:34
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Internet Explorer posted:It just seems like 12% loss is a good amount when you start talking about hundreds of thousands of cars on the road. It's one thing for a cellphone that uses a tiny fraction of the power, but it just seems wasteful at a fleet level. If I'm a business looking to install courtesy chargers in my parking lot, it's also going to ensure I don't use those.
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Oct 14, 2016 19:22
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Are there any plans for 277V, 347V, 480V, or 600V charging stations in the future? (Not for homes but at charging stations and businesses where people don't want to wait super long, Plus if you need to set up a system to charge multiple vehicles it's more efficient materials-wise.)
Three-Phase fucked around with this message at 21:52 on Oct 15, 2016 |
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Oct 15, 2016 21:47
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How's that? Current electric cars can't handle arbitrary AC voltages, so you'd have to build transformers near the charging points. If you're talking about DC charging, I believe they already require high voltages but the charging stations are expensive pieces of kit.
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Oct 16, 2016 06:57
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The tesla wiki has this to say:quote:For those of a technical bent, here’s how a typical Supercharger (in this case, the one at Port St Lucie, FL) is configured: the eight bay setup, like the one shown on the first page of this chapter, takes a 12 kV, 750 kVA feed from the Utility, steps it down to 480V three phase on site, pushes that into 2000A switchgear which feeds four banks of Supercharger (SC) units (one for each pair of “pods”) at 480V/200A. Each unit contains twelve 10 kW rectifiers (the same “charger” that is found in Model S) giving a total of 120 kW per pair of pods. I dunno why Tesla would bother transforming 12kv into 480v with their own equipment, utilities would do that for you and absorb the cost of maintenance on HV. It's not like they're requiring 4kv or something, 480v is common. I'm going to assume that's a mistake by the author.
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Oct 16, 2016 16:20
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MrYenko posted:Tesla model S's will charge at up to 240v/40a with just the portable cable, which is 9.6kw. The wall connector allows up to 48a, which is 11.5kw, or 72a with the high-amperage charger option, which is 17.3kw. Legacy dual-charger Model S's will charge just a smidge faster, though I can't find numbers. Legacy dual was 80A/240V on my previous car, but I forget the kWs and I don't know the math.
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Oct 16, 2016 20:39
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Subjunctive posted:Legacy dual was 80A/240V on my previous car, but I forget the kWs and I don't know the math. The use of electricity post‐dates the French Revolution, so it’s as simple as multiplying volts by amperes. 19200 W, or 19.2 kW.
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Oct 16, 2016 20:43
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angryrobots posted:I dunno why Tesla would bother transforming 12kv into 480v with their own equipment, utilities would do that for you and absorb the cost of maintenance on HV. It's not like they're requiring 4kv or something, 480v is common. I'm going to assume that's a mistake by the author. The only thing is that 2000A is fairly substantial. It's probably built as a packaged "unit substation" where you have a step down transformer that directly feeds into a 480V switchgear lineup to feed all the charging stations. There isn't a ton of maintenance on the HV side - they probably just have a fused disconnect switch that feeds into the high side of the 750kVA transformer. Maybe some metering/relaying too. I did a little digging and with the Tesla Supercharger, 400V at up to 250A is bandied about (100kW assuming output is DC). That's quite a bit of power on a cord. Platystemon posted:The use of electricity post‐dates the French Revolution, so it’s as simple as multiplying volts by amperes. P=IV only if it's DC or single-phase AC with no power factor (phase shift or severe difference like distortion between the voltage and current waveforms). You've just got to be careful with AC. Three-Phase fucked around with this message at 21:03 on Oct 16, 2016 |
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Oct 16, 2016 20:59
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Three-Phase posted:I did a little digging and with the Tesla Supercharger, 400V at up to 250A is bandied about (100kW assuming output is DC). That's quite a bit of power on a cord. The cords are hefty, and short. I've heard that they experimented with liquid cooling for some part of the cable/connection. You only get 400/250 when your battery is almost drained, though.
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Oct 16, 2016 21:01
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I wonder what would happen if you took a pair of bolt cutters to the cable while it was charging. I'm sure there's an automatic cut-off, but I'm also sure that it wouldn't respond instantaneously to exposure of the conductors.
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Oct 16, 2016 21:03
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It might have a sheath that could detect it. I suspect though that cutting into a high-power cable always turns out badly. My charger is on a 100A circuit, and if you took a bolt cutter to it you would probably lose. I don't have to have any failsafe in place for it, and it runs in an accessible location.
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Oct 16, 2016 21:08
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Sagebrush posted:I wonder what would happen if you took a pair of bolt cutters to the cable while it was charging. Well lessee... utility is an infinite bus at 12kV... air-cooled 750kVA transformer, 2000FLA secondary with an impedance of say 5%... So the transformer secondary can theoretically supply 40,000 amps in a fault (2000A/0.05). Now going further downstream as it goes through cables and such that fault level will probably drop down quite a lot, but that's the starting point. Bear in mind that in a short circuit you break stuff from the magnetic forces generated by that much current flowing - cables can violently whip, busbars can get warped, and stuff like that. There are a couple of different ways to protect from the cables shorting or a ground fault occurring. It depends on how the system is setup, like if it's supplying AC or DC to the car and how and where the fault occurs. One advantage to the DC output (going through a rectifier) is that if a fault is detected like a short circuit, the rectifier can shut itself off and kill power in less than 10 milliseconds. That would limit the energy delivered to the fault instead of waiting for a circuit breaker to open. The rectifier circuit probably has fast-acting semiconductor protection fuses on the AC side, and that is designed to rapidly kill power if a fault occurs to protect the rectifier. Replacing fuses in those are relatively easy, replacing destroyed power components can be a bitch. Just to reference: 12kVAC ----> Transformer ----> 480VAC ----> Something ----> Charger Rectifier/Controller -----> Car Three-Phase fucked around with this message at 21:21 on Oct 16, 2016 |
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Oct 16, 2016 21:11
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I believe superchargers deliver DC, bypassing the car's onboard chargers/transformers.
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Oct 16, 2016 21:22
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Tidbit on the chargers: there's talk I've heard about designing the home chargers to actually work in "both directions". So if the charger receives a signal from the utility company it takes energy OUT of the car battery and supplies it into the power grid. Not a lot of power, but if you multiply it by a million cars it adds up. I believe the goal is to use this to support grid stability if there's a fault or problem somewhere. (Actual control and implementation of this is a million times more complicated than what I described it as.)
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Oct 16, 2016 21:30
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I'd heard about that rumour for PowerWall stuff, but not car chargers. Are the cars even electrically able to discharge through the charging port? That surprises me!
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Oct 16, 2016 21:32
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Subjunctive posted:I believe superchargers deliver DC, bypassing the car's onboard chargers/transformers. Yeah, that's the standard method of accomplishing fast-charging right now. The major limitation isn't the ability of the battery to accept charge, but the load capacity of the onboard inverters and rectifiers. Make a big beefy unit offboard that plugs directly into the cells and handles all the balancing and such remotely, and you can push energy as fast as the cells will accept it. I'd imagine that if you try to push much past a 1C charging rate (i.e. 1 hour from 0 to 100% SOC) you'll start to run into battery limitations, like pack cooling or hydrogen evolution.
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Oct 16, 2016 21:34
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Sagebrush posted:Yeah, that's the standard method of accomplishing fast-charging right now. The major limitation isn't the ability of the battery to accept charge, but the load capacity of the onboard inverters and rectifiers. Make a big beefy unit offboard that plugs directly into the cells and handles all the balancing and such remotely, and you can push energy as fast as the cells will accept it. I *think* the balancing is still on-board, but I'd love to find the details.
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Oct 16, 2016 21:38
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https://teslamotorsclub.com/tmc/posts/908021/ and subsequent have some interesting tidbits and pictures.
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Oct 16, 2016 21:46
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Three-Phase posted:The only thing is that 2000A is fairly substantial. It's probably built as a packaged "unit substation" where you have a step down transformer that directly feeds into a 480V switchgear lineup to feed all the charging stations. And we have to meter it whether primary supply or secondary, and a primary metering stand is a far more expensive initial cost so that's a wash, or negative. It just seems like a future maintenance headache for tesla, at what benefit?
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Oct 16, 2016 21:49
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Yeah, especially stuff like splicing and terminating gets complicated with medium voltage cables that have different layers inside them like shields and semiconducting layers. One other advantage MIGHT be power quality. If you just connect chargers to a store's power (120/208 or 277/480) I'd be concerned about the switching section of the charger (rectifier) throwing garbage back into the power system and causing problems. That depends a lot on how the charger is designed. Older equipment used to need isolation transformers or reactors before you had any power semiconductor systems (rectifiers, drives) but I think newer equipment that switches really fast may not need that as much and be a lot "quieter" as far as interference goes.
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Oct 16, 2016 22:20
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Good lord they are oil-cooled as well. Wow.
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Oct 16, 2016 22:22
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I just purchased a 2016 Hyundai Sonata Plugin Hybrid. The power company offers a $500 rebate on level-2 charging stations. Any suggestions on models? I'd plan to have it installed in the garage pretty close to the car.
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Oct 17, 2016 20:12
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Question: do hybrids and EV dramatically lose their resale value as they reach the end of their battery pack's life? I'm taking about trading in a vehicle say 10 years down the line with 150k miles.
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Oct 18, 2016 01:11
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Pretty sure just about everything dramatically loses its resale value after 10 years/150k miles.
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Oct 18, 2016 03:16
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Godholio posted:Pretty sure just about everything dramatically loses its resale value after 10 years/150k miles. Well that is a very good point... I don't want to be the vehicular equivalent of the "23 inch CRT great condition - only $200!" wackos.
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Oct 18, 2016 04:44
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It's really, really hard to say. $8000 gets you a 2008 prius with 100,000 miles, or a 2014 nissan leaf with 20,000 miles.
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Oct 18, 2016 05:08
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Of course, one of those is a Toyota with a stellar reliability reputation, and the other is a Nissan with known-questionable battery life and that was sold with a metric fuckton of cash on the hood between government and retail rebates. Re: 12KV vs 480V, at least locally the company I work for gets a (minor) discount by taking its ~18MW of power as a few 12KV feeds instead of a shitload of separate 480V feeds. Means we need to maintain our own 12KV->480V gear, but we need to keep some electricians on staff anyway.
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Oct 18, 2016 06:14
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IOwnCalculus posted:Re: 12KV vs 480V, at least locally the company I work for gets a (minor) discount by taking its ~18MW of power as a few 12KV feeds instead of a shitload of separate 480V feeds. Means we need to maintain our own 12KV->480V gear, but we need to keep some electricians on staff anyway. However, if tesla is going to keep a staff of qualified employees to maintain and repair their charger sites...I'd like to know about it, that could be an interesting career change. I like cars, I like electricity. 
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Oct 18, 2016 18:40
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I need to find that YouTube video of this plants 12kV feed (I think a lower voltage higher current side of an former) on fire. It's quite a light show.
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Oct 18, 2016 19:42
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The Bolt looks really intriguing but I'm not particularly confident in first year GM production quality, combined with a dealer network that's questionable for well established vehicles let alone brand new ones. If only the Leaf had a 40kWh battery...
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Oct 19, 2016 03:42
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IOwnCalculus posted:Of course, one of those is a Toyota with a stellar reliability reputation, and the other is a Nissan with known-questionable battery life and that was sold with a metric fuckton of cash on the hood between government and retail rebates. The hybrid cycle doesn't really degrade as the battery ages. Old prius's (priora?) are one of the most reliable vehicles on the road, since the electric motor and regenerative braking takes so much strain off the brake pads, plus electric motors are relatively maintenances free. The batteries do age and degrade, but most of the savings of a hybrid is in the electric motor providing the start/stop motion of the car, and even a diminished battery is still able to provide that. In contrast a pure EV loses outright range as the battery ages, which is much more of a loss to the owner. It's one thing when a 300 mile tesla loses 10% of it's capacity, its a whole other when a 40-mile Leaf does.
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Oct 19, 2016 07:00
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ehnus posted:The Bolt looks really intriguing but I'm not particularly confident in first year GM production quality, combined with a dealer network that's questionable for well established vehicles let alone brand new ones. Funny this took my brain a second to realize you werent talking about hockey.
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Oct 19, 2016 07:18
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Regarding Toyota - inrecently test drove a Hybrid RAV4. I was pretty impressed. The vehicle looked and felt really well-made and durable and the performance even in ECO mode was pretty good.
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Oct 19, 2016 11:00
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I don't understand why Toyota are so reluctant about battery electrics when they've been spearheading hybrids for so long.
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Oct 19, 2016 11:06
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