Porsche claims they can charge their electric cars at 350KW - Page 1
Forum section: electronics / general

author: mcinque
author_rank: Unknown
timestamp: July 19, 2017, 09:19:41 pm
content: https://electrek.co/2017/07/14/porsche-350-kw-ev-charging-station/QuoteHow can they manage so much power rate with the resistance of a removable connector?Few milliohms raise in the resistance of the connector because of dust and / or oxidation would generate so much heat at that power rate that could bring easily to flames.Is their claim purely advertising or do you think that result is achievable with a removable, end-user operated connector?

author: Dubbie
author_rank: Unknown
timestamp: July 19, 2017, 09:23:59 pm
content: With a well engineered new connector you can basically choose your contact resistance and design to meet it. It's not like they are bound by any existing standards.

author: sleemanj
author_rank: Super Contributor
timestamp: July 19, 2017, 09:31:31 pm
content: There is more than just porche working on it, see the wkipedia on the ccs connector.Remember voltage factors into power delivered (IV), but effectivly not into losses in contact resistance (IIR). I don't know what voltage the connector is ultimately rated for.

author: KE5FX
author_rank: Super Contributor
timestamp: July 19, 2017, 09:31:53 pm
content: Where is this 350 kW going to come from?When will people realize how much better it would be to have standardized swappable batteries?Grumble.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: July 19, 2017, 09:32:33 pm
content: Must be raising the voltage to achieve that because 450A through that pissant cable doesn't seem safe. It'd be based on a similar system as Power Delivery and Quick Charge: default at a lower state until it gets the all clear so it should have no other safety issues.

author: 2N3055
author_rank: Super Contributor
timestamp: July 19, 2017, 09:51:36 pm
content: They claim 800V , so about 450A... That is possible..Problem is not in that.. Problem is that if you want to put only 10 of these to a parking lot that is 3.5 MW.. That's megawatts..And if we all have electric cars, you won't need only 10 in one place.. You'll need more..What are they going to do, put a miniature nuclear power plant on every parking lot for charging...We had lots of problems getting 25 KVA power out in the field for a small Type 2 EV charger ..Most of the time electrical company tells you they have to put a separate power transformer substation for your charger... If you're willing to pay...Grid is currently not developed for this kinds of load, at least not where I live...

author: Avacee
author_rank: Unknown
timestamp: July 19, 2017, 09:54:41 pm
content: According to a report from the National Grid (UK's power distribution network) the UK will need the equivalent of 5 new nuclear power plants the size of Hinckley C to handle the increased demand for charging EVs (Electric Vehicles).http://fes.nationalgrid.com/media/1253/final-fes-2017-updated-interactive-pdf-44-amended.pdf- Section 5.3Quote

author: StillTrying
author_rank: Super Contributor
timestamp: July 19, 2017, 10:17:55 pm
content: https://electrek.co/2017/07/14/porsche-350-kw-ev-charging-station/So there's 2 800V 450A cores in that cable, and a 350kW transformer in the boot of the car ?Why doesn't someone simply put a windmill on the roof of an electric car, the faster you drive the more it will keep the battery topped up.

author: John B
author_rank: Frequent Contributor
timestamp: July 19, 2017, 11:06:19 pm
content: Quote from: 2N3055 on July 19, 2017, 09:51:36 pmSolar roadways in the carpark.

author: Red Squirrel
author_rank: Super Contributor
timestamp: July 20, 2017, 05:56:15 pm
content: Maybe I'm underestimating how much amp hour a car battery pack is, but is it even necessary to charge at such a high rate? Why not charge at a more normal rate that can use a 240v 30 amp outlet or something or even 120 15 amp? A typical use case is going to be that you plug it in when you get home from work, so even if it takes several hours or like 10 hours that would be acceptable. Probably easier on the battery too.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: July 20, 2017, 06:03:32 pm
content: Quote from: Red Squirrel on July 20, 2017, 05:56:15 pmBecause you want to stop at a "gas/petrol" type station for 2 minutes to get charged and go.

author: rstofer
author_rank: Super Contributor
timestamp: July 20, 2017, 08:34:32 pm
content: My Chevy Bolt has a 60 kWh battery and should go for about 200 miles - weather contributing. It is rated at 160 kW so as not to starve the 150 kW motor. So, about 200 HP...There are a number of charging alternatives but the little portable charger that comes with the car runs on a 120V 15A circuit so, at best, it is 1.5 kW. It takes a while to charge the battery if it gets very far down.I also have a 7 kW (?) charger that requires 240V at 30A and commercial establishments (like Walgreen's in my area) have larger and faster chargers. GM recommends an 80 kW charger to ensure a consistent 50 kW rate.One of the cool things I haven't tried (and probably won't) is "one pedal driving". No need to use the brake pedal, just ease up on the gas. I don't know how it would work in an "oh my god" situation. The car does have all kinds of automatic braking features.https://en.wikipedia.org/wiki/Chevrolet_BoltGM tamed it down to 266 lb-ft of torque after complaints of "lively" acceleration in the lighter Chevy Spark EV with over 400 lb-ft. I miss that car...All in, I don't see how the grid can support massive numbers of EVs. As it is, PG&E has some kind of special rate for EV owners but we haven't even considered applying. Somehow, it always seems that their new rates cost us more money!I don't really expect a huge number of EVs any time soon. In my town, I have only seen one other Spark EV and a couple of Chevy Bolts. They're not sales leaders. Range is the issue; the Spark EV was only good for 80 miles and the Bolt for around 200. There are times when 200 isn't enough or, rather, even if it were, the time to recharge is too long to get to work the next day. Maybe when employers start installing charging stations. Don't count on it, the cost will be HUGE!

author: StillTrying
author_rank: Super Contributor
timestamp: July 20, 2017, 08:35:08 pm
content: Electric trucks/lorries."should be ready in February 2016"let me guess - it never happened ?http://insideevs.com/scania-test-electric-trucks-electric-roads/

author: rstofer
author_rank: Super Contributor
timestamp: July 20, 2017, 08:37:18 pm
content: Quote from: RGB255_0_0 on July 20, 2017, 06:03:32 pmTesla is arranging for stations to just swap the battery pack. Like I would give up my brand new pack for some old POS...

author: Fsck
author_rank: Super Contributor
timestamp: July 20, 2017, 09:18:07 pm
content: how are they going to make that idiot proof? I smell lawsuit material when someone does something stupid with 350kW.

author: KE5FX
author_rank: Super Contributor
timestamp: July 20, 2017, 09:27:37 pm
content: Quote from: rstofer on July 20, 2017, 08:37:18 pmWhy in the world wouldn't you? The battery's performance history will be precisely characterized and monitored.What's the point of owning a battery?

author: rstofer
author_rank: Super Contributor
timestamp: July 20, 2017, 10:25:18 pm
content: Quote from: KE5FX on July 20, 2017, 09:27:37 pmSo, I drive my brand new Tesla right off the showroom floor and head south to LA. Somewhere along the way I stop into a charging station and they swap my brand new battery for the one somebody with 100k miles left for charging. Somehow, I don't think so. Now, if my car had the 100k miles, sure, I might take a chance.The battery on the far lesser Chevy Bolt will cost $15k to replace and I think I heard that the Tesla battery packs is about $45k. I see a black market forming on the horizon. Right now they steal catalytic converters but that is chump change compared to the cost of batteries. Like stealing copper wire, the devil will be in the details. Gotta make sure to not get fried!https://forums.tesla.com/forum/forums/tesla-model-s-85kw-battery-replacement-cost

author: Red Squirrel
author_rank: Super Contributor
timestamp: July 20, 2017, 10:27:20 pm
content: They need to come up with some standards for charging stations (ex: the plugs/voltage) and the battery packs. What would be neat is if they have a few different sizes, but for normal cars they would be small battery packs that can be lifted by one person, and they would slide in somewhere on the car and have a backplane. Most vehicles would have several of them in parallel. This could also make electric cars cheaper, as someone like me who mostly just sticks to driving in town I could get away with like 30km range. They could then have exchange programs that you can choose to use if you want, great if you're out of town. Or you could have spare battery packs on hand at home etc. They could perhaps even treat it like a rental, depending on the service you choose. Ex: you drop off your battery but choose the service where they keep it and charge it for you, and rent you another. You come back another time and get your battery back. Or you could do a full exchange. They could offer various options. These services would be ideal for people from out of town, for example. Normally you'd just charge at home after work. heck a lot of these stations could be practically in the middle of nowhere and run off mostly renewable energy, solar panels and wind turbine. The battery packs that are sitting on the chargers would literally be THE battery packs for the building itself. There would always be batteries on the go, with some that are fully charged. The station would pretty much run itself.You could also buy extras to have at home on a charger that's ready to go. You can either plug the car in the charger or plug the battery in the charger. All the interconnects would be standard. Idealy, the charging logic would be in the battery pack itself, that would allow to only have 4 large terminals, 2 would be to power the car, and 2 would be for charging, the internal circuitry would then manage the balancing of each individual cell pack. Either make the voltage very standard, or have a standard comm port for the charger, that would dictate how much current is being put in so the pack knows how much to draw, but I'm thinking having a strict standard voltage would be best bet, then all the charger needs to do to dictate current is to lower voltage, ex: current limiting, then the internal pack knows to dial down how much it's drawing. At a charging station you would then have the option to pick the charge rate you want and pay more for faster, for example, and that would simply alter the current limit rate of the charger. Chargers on a certain breaker size such as 15 amp would then current limit accordingly to maximize use of that circuit. Acharger would really just be a power supply, it would be up to the battery pack itself to manage charging. This would even allow for different battery tech to be introduced in the future without having to change the charger infrastructure/standard. Would open a lot of doors.Basically make a few standard battery pack formats where the size/connection and voltage is standard, the rest is up to the vehicle/battery pack. Could even have some NI-MH ones that are cheaper but much lower capacity.Of course something like this would need to be very well engineered for safety too, if you have average people handling these. But it's not really any different than jerry cans. you're always going to have idiots filling their lawnmower with a cig in their mouth and having gas spilling everywhere and practically blow themselves up.

author: ovnr
author_rank: Frequent Contributor
timestamp: July 20, 2017, 10:34:03 pm
content: Quote from: rstofer on July 20, 2017, 10:25:18 pmThe point is that you wouldn't own the battery. When it shits itself, you get a new one for free. Or, more likely, when a battery gets close to EOL, it gets swallowed by the charging station and picked up for recycling.You'd "simply" pay a usage fee on top of the kWh cost to recharge it. Recharging it at home would still incur that cost, just with the power billed on your normal power bill. And yes, I know Tesla offers free supercharging; this is strictly for future vehicles.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 21, 2017, 02:42:58 am
content: Quote from: rstofer on July 20, 2017, 08:34:32 pmOr more likely they needed to make room for a way more profitable "sport edition" sometime in the future. Making a car "Tesla-like" is a good selling point.

author: Gromitt
author_rank: Regular Contributor
timestamp: July 21, 2017, 11:51:52 am
content: Quote from: StillTrying on July 20, 2017, 08:35:08 pmYes, it did. Not in february, but in june 2016.https://www.cnet.com/news/sweden-opens-1-2-mile-long-electric-highway-for-trucks/

author: StillTrying
author_rank: Super Contributor
timestamp: July 21, 2017, 12:30:57 pm
content: Quote from: Gromitt on July 21, 2017, 11:51:52 amPerhaps it's just me that thinks it's very impractical. About 250A needed through those 2 moving contacts, per truck.

author: CJay
author_rank: Super Contributor
timestamp: July 21, 2017, 03:44:16 pm
content: Quote from: RGB255_0_0 on July 20, 2017, 06:03:32 pmThat's the killer for the current (pun, natch) crop of EVs, the time it takes to charge. It's fine if you only commute a few miles a day as I do now but it completely rules out a spur of the moment trip to Cornwall or Scotland or wherever because I just can't guarantee I will find a charge point or that I will be around for long enough to let the vehicle charge enough to get me home.With liquid or gas I can fill the tank in a couple of minutes.We need Mr Fusion!

author: rstofer
author_rank: Super Contributor
timestamp: July 21, 2017, 06:52:26 pm
content: Quote from: ovnr on July 20, 2017, 10:34:03 pmThat doesn't sound right. If the battery pack is $45k, that represents 15k gallons of gas (more or less) and at 25 MPG, I could drive for 375k miles. Why would I buy an electric car if I had to concern myself with battery pack depreciation. In fact, that's why I leased both the Spark EV and the Bolt. I don't want to get into the battery replacement part of the life cycle. The batteries are guaranteed for 8 years for the Chevy but that still amounts to having to add about $150/month to the cost of the car.As to cost to operate: Chevy is thinking 3 miles per kWh when they rate the battery life. A kWh around here is about $0.36 so we're driving for $0.12/mile. It was better at the old house where we had solar. A kWh cost $0.15 so $0.05 per mile. My grandson could drive like a senior citizen and get as much as 7 miles/kWh so that was a little over $0.02/mile. Now we're talking!My truck gets about 17 MPG so it costs about $0.18/mile. The electric car isn't a substantially cheaper way to go (33%) but it is more fun. Driving the Spark EV low and slow would result in 1/9th the cost of the truck.As long as gasoline is in the $3/gal range (used above), I'm not sure a battery car saves enough money to matter. I don't drive much so I can't save much. It could be argued that I should sell them both and just bicycle the 3k miles/year. But here's the thing: I'm a retired EE, of course I want a battery car!The reason they tamed down the Bolt from the Spark EV is the traction control setup shifts the drive from side to side as a function of wheel slip. This tends to make the car veer one way or the other at a fairly fast rate. Folks aren't used to this, particularly us rear wheel drive types. I don't care if the back end steps out on a rear wheel drive car but keeping up with the moving torque on the front wheel drive takes a little more concentration. And then there is "Sport" mode on both cars...

author: mcinque
author_rank: Unknown
timestamp: July 21, 2017, 06:54:26 pm
content: Quote from: 2N3055 on July 19, 2017, 09:51:36 pmThis is absolutely true; even in a little city would be unsustainable, so can we say that fast charge electric cars are only apparently ecologic and unpractical?

author: rstofer
author_rank: Super Contributor
timestamp: July 21, 2017, 06:56:37 pm
content: One thing that is often overlooked is the essentially zero cost of maintenance. A tire rotation every 7500 miles and an environmental air filter replacement every 15000 miles. And NEVER a smog check!Interesting thing: The tires on the Spark EV are different diameters front to rear. So, no tire rotation! Just replace the environmental air filter every once in awhile if you happen to think about it.

author: mcinque
author_rank: Unknown
timestamp: July 21, 2017, 07:25:55 pm
content: Quote from: rstofer on July 21, 2017, 06:56:37 pmNot even the transmission/gearbox?

author: Nusa
author_rank: Super Contributor
timestamp: July 21, 2017, 07:45:56 pm
content: Quote from: mcinque on July 21, 2017, 07:25:55 pmProduction electric cars generally have a simple single-speed gearbox. Electric motors have a large enough torque range that there's not much need for shifting.

author: KE5FX
author_rank: Super Contributor
timestamp: July 21, 2017, 09:23:11 pm
content: Quote from: rstofer on July 21, 2017, 06:52:26 pmSo.... first you say it's important to you that you own the battery, then you say you're leasing the whole car?Rest assured, the lessor is accounting for the battery life, and they don't have your interests in mind when they do it.QuoteThe car would be that much cheaper to buy or lease if it didn't come with a hardwired battery. You would then lease the battery, paying only for the coulombs you actually put through it. With standardized form factors, manufacturers could focus on improving the underlying technology and compete to offer the best deals.Right now, it's as if you're forced to buy flashlights that only work with Duracell or Energizer batteries.

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 21, 2017, 09:36:15 pm
content: Quote from: Nusa on July 21, 2017, 07:45:56 pmWhat about bearing checks, motor coolant, brake pads, brake fluid, wiper blades and wiper fluid, AC pressure checks, exc?Oh, and apparently the Tesla S does require transmission oil.

author: mc172
author_rank: Frequent Contributor
timestamp: July 21, 2017, 10:34:42 pm
content: Seems a bit like 350 kW "PMPO" to me.

author: rstofer
author_rank: Super Contributor
timestamp: July 21, 2017, 11:20:58 pm
content: Quote from: Cyberdragon on July 21, 2017, 09:36:15 pmOn the Bolt, the maintenance schedule is attached. The schedule is for routine maintenance. Things like odd noises and brake problems are outside the schedule. Considering the dynamic braking, both automatic and manual from the steering wheel mounted paddle switch, I suspect brake life should be pretty good.The section on Batteries (page 2) is laughable - it reads like it was a copy and paste from a regular auto.For scheduled maintenance, you will note that tire rotation is every 7,500 miles and environmental air filter replacement is every 15,000 miles. The first important scheduled maintenance is at 150,000 miles and consists of a coolant change. At the end of the 3 year term, we might be ready for the first environmental air filter replacement. We won't be anywhere near 150,000 miles!https://my.chevrolet.com/content/dam/gmownercenter/gmna/dynamic/manuals/2017/Chevrolet/BOLT%20EV/Maintenance%20Schedule.pdfI haven't checked the tires to see if they are of different diameters, front to rear, as they are on the Spark EV. Wouldn't that be a hoot? I'm not a big believer in tire rotation in any event. I usually move the fronts to the rear and replace the fronts - when it's time. I would far rather lose a rear tire than a front, especially on a front wheel drive car.ETA: This maintenance schedule must be a nightmare for dealers. They make most of their profit in the Service Department.