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But the car batteries and cables need active cooling to soak up the 450kW safely.
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Read more.Quote:
But the car batteries and cables need active cooling to soak up the 450kW safely.
This could very well change the electric car game.
I'd imagine it will fall down to how much these cost to implement along with how they'll affect battery lifetime.
You think?Quote:
But the car batteries and cables need active cooling to soak up the 450kW safely.
Fast charging is great, but certainly in the UK there needs to be some sort of work to standardise chargers, how you pay for them etc.
Well, the UK could use these Combined Charging System chargers, and give the power away for free, just like this scheme.
Tesla will in the future support CCS as well apparently.
WOW! if something goes wrong the lithium batteries explode taking a few blocks in the street.
Great idea. The current problem is getting the same power that can power 150 homes to each charging space. A motorway service station with several spaces will need it's own substation and high voltage supply I guess.
Battery lifetime: 6 charges. Just what the manufacturers would like....
Thats nothing, in a year or so it will be :
https://www.youtube.com/watch?v=p46VOwNUOdw
It's BMW too....& so long as the BMW has star marked tyres, it should be well protected...but if you fitted non approved tyres... well... puppies will die at the very least.
Hows this affect the life of the batteys? does it shorten them any compared with standard charging?
Generally it's the heating and cooling that'll cause problems and rapid "ageing" of the battery. The more intense the heating, the faster the individuial little itty bitty cells short out, removing their capacity from the overall effort (this is what has been explained to me by people who proport to know so if I'm wrong, please someone correct me). I suspect if active cooling is required, that's probably at the moment purely to keep the battery within safe operating conditions. Endurance is another matter and something they'll be analysing very carefully under an electron microscope when they autopsy some batteries that have been through this. Interestingly, Prius batteries from the very first ones are showing surprisingly little degredation.Quote:
Originally Posted by Platinum
I remember a couple of decades ago, we used to say one fast charge for every two slow charges for "performance" batteries back then but I think that (considering we were talking about lead acid batteries) that was due to accumulation of sulphates on the electrodes which were removed by the slow charger, so a different method of failure. The point being that they may (certainly initially) say you can only do so many fast charges before you void your warranty.
There's also the issue of power factor when you're looking at all of this. Even standard fast chargers run at the limit of your grid's connection (now they have changed from KW to KVA with smart meters, gits). You have a few of these running and on the face of it the grid load will be huge, never mind if it's a huge inductive load meaning the grid has to provide a good whack more energy than is being used.
Personally, when looking at the mobile phone as a use case, I have it slow charge wirelessly overnight which takes a good few hours but I also keep a fast cable charger by the bed as well to allow me both options. I'd certainly not put any battery that I wanted to last as long as possible through rapid charging. There is a sweet spot charging rate at which you can shove in pixies before it starts to significantly impact battery life - I think most fast chargerse for phones work on this (although this sweet spot changes as the battery charge increases so the charge rate drops over time).
Lithium batteries don't 'explode' in the conventional sense, they burn rapidly when they're badly damaged. However more modern cells are far more tolerant of electrical neglect and manufacturers frequently include the results of such tests in their datasheets. Large packs like this have carefully-designed charging and BMS systems which will stop charging if anything goes awry.Quote:
Originally Posted by lumireleon
I don't expect they'd install say a service station with enough capacity to simultaneously provide maximum power to each charging station. The supply would most likely be provisioned based on average demand of some sort.Quote:
Originally Posted by badass
I remember reading a paper fairly recently showing the wear caused by fast charging is less than often claimed. Also, this article doesn't state anywhere that that's a full charge in 6 minutes, or anything close to it. It could be something like a 25% charge which wouldn't be far off the 30 minute 'fast charge' commonly specified for this sort of battery anyway. One of the most time consuming bits of charging li-ion batteries is the current taper (CV stage) after the 'fast' part at full current, and IIRC some car manufacturers deliberately leave this part off anyway (or only do it as an option if you're planning to drive a longer distance) to maintain the batteries at a lower SoC with the aim of improving cycle life.Quote:
Originally Posted by gagaga
Not around here they haven't - sure they can measure kVAh but domestic customers are still billed for kWh.Quote:
Originally Posted by philehidiot
I'd be quite surprised if these charging circuits didn't have some decent form of power factor correction given even things like phone chargers have mandated minimum power factors in many countries now.Quote:
Originally Posted by philehidiot
Agree with the rest though - while there's some truth in many of the concerns, I think some are overblown and repeated as gospel with little evidence to back it up. As a bit of an anecdote, I fairly recently dug out and tested some 18650 cells I've had lying around for close to 10 years and only cycled maybe a dozen or so times. Upon measuring internal resistance and capacity, I was pleasantly surprised to find they're nearly all right on original manufacturer's spec! And some of them have even been stored at fairly high SoC too. One of the ones which seems to have lost a bit more capacity than the rest is an older Chinese-made one and not from one of the big 18650 manufacturers, and has been cycled a fair bit more than the rest.
It hasn't happened here because I keep saying sod off to a smart meter.... If you examine your bill, you may find that they've changed the connection limit. On consumer units there's a breaker for 9KW and now they've changed the connection limit on the bill from 9KW to 9KVA (who's gonna notice?) and there's a breaker in the smart meter which will fire off before the consumer unit one which is set to 9KVA, which is obviously less than the 9KW (although the mathematician in me hates these mathematically identical terms being used for different meanings, damn engineers). Why have they done this? Well, so they can begin to take into account power factor for consumers but also you'll note that a (I think it's Tesla) fast charger for domestic EV use is rated at.... 7KVA. Handy that. Just to ensure you need to pay more for your grid connection. Very agreeable.Quote:
Originally Posted by watercooled
I'm sure you're right that there will be the usual switchable banks of capacitors to correct the power factor but my understanding is you can't completely merge the out of phase V and I sine waves? Just out of interest, what happens if you're out of phase by 90 degrees (and so the cosine of theta between voltage and current = 0?). Does that mean there's zero output?
Watts are volts x amps. A KVA == KW, it's the same unit...