400V vs 800V – Watts the difference for EV Charging?
My name is derek reilly. Today we are joined by dr ewing mcturk. He is on the channel before where we did a piece on the wltp ratings that manufacturers give their vehicles so make sure you go back and check that out ill. Stick: a link on the screen and in the description. But i was talking talking to dr ewan about another subject, matter thats starting to creep up with manufacturers, and that is the difference between a 400 fold architecture and an 800 volt architecture and how that can affect charging times etcetera. So i dont know a lot about it, and i said dr young mcturk hopefully well know a bit about it, so you and how are you im good thanks, thanks for having us back on derrick yeah, not at all uh, you uh, we were chatting before we Hit record and you were saying that you had a fairly decent understanding of the whole uh the difference between and why manufacturers may go one way or the other, but youve done a bit of research on it, just to confirm everything that is up to date, so Ill happily hand over to you and uh. Let us know the difference between 400 volts and 800 volts, not just its double yeah, but obviously yeah. There is a bit more to it than that so yeah. For the best part of a decade, electric vehicles have been running 400 volt battery packs, um or their boats, so that translates into 96 lithium ion cells in series.
When theyre fully charged, they are typically about 4.1 to 4.2 volts each multiplied by 96. You get to 400 volts so when youre, when youre connecting these cells in series, its positive to negative, positive to negative and so on and thats building up the voltage of the entire system of the entire battery pack, its like you know, making a staircase taller and Thats, how you get the yeah the overall system voltage um, however, that in itself isnt necessarily going to be enough for your needs. You might need additional capacity. You might need to widen that staircase. So youll put the cells in parallel as well so thats, where you connect them positive to positive negative to negative and thats how you widen that staircase, so you can get even more electrons up and down them now for the the electric vehicles of the 2010s. You know the nissan leaf, the the volkswagen e golf and so on 400 volts was fine um, because that meant that uh, when you were rapid charging them on a 50 kilowatt, uh rapid, you know im saying rapid charger but of course, in the republic of ireland, Youll refer to them as fast chargers, which is what we refer to them in scotland, as as ac so um, you know youre kind of 22 kilowatt stuff, so yes dc charging is where we refer to chatham or ccs uh. It saves me having to translate on the flag, but so for your 50 kilowatt dc charger.
That was the main state, and that meant that uh, you know that charger would be pumping out dc. You know direct current um. It was typically 400 volts maximum that it would be engineered towards because it was all built around. You know your earlier kind of nissan leaf, your your um, bmw, i3 and so on, and then the maximum current that you typically got on those cables was about 125 amps. So you know your power is current times, voltage 125 multiplied by 400 thats, your your volts, of course, and multiply by the current. Then you get 50 kilowatts and that was was fine. But then we started to get um considerably more ambitious with the capacity of the batteries we were looking at and the charging speed as well, and if we maintained a 400 volt system voltage, we needed to up the current and in order to up the current, we Needed bigger heavier cables, so you know you were starting to get up towards 200 300 amp cables um to be able to supply enough power to these vehicles, but then along came the likes of the porsche tai cam, which can charge at in excess of 270 kilowatts. So that is going to be some seriously fat cabling if that was 400 volts. So that is why manufacturers, starting with porsche, started to switch to 800 volts architecture, so they were taking the same capacity of battery pack. Its made up of you know hundreds or thousands of individual cells, depending on the exact type of size of cells that youre using and they basically doubled the the height of the staircase um and halved the the width of it.
So, instead of having um, you know so many cells in series and so many in parallel, they would have double the number in series and then half a number in parallel because, as i said before, power is current times voltage. So if you double the voltage to get a given amount of power, you can half the current, and that means that when you are dealing with such high power, 200 300 or in the case of the ccs standard, today, 350 kilowatts, that is where uh you can Get away with much thinner, cables, much cheaper cables, youll get less uh, resistive kind of power losses as well um and, as i say that the higher voltage enables that, with a thinner, lighter cable, thats easier for you to actually physically unplug from the charger and plug Into the car itself and porsche you were saying were the first to come along with the standard, knowing that they were going to do high performance, electric vehicles and people would want to fill up faster, a bigger battery, etc. Absolutely yeah they were, they were the first to market um and then, of course, they effectively re badged. Audi e tron gt shares that architecture too, and then hyundai and kia with the ionic 5 and the ev6 again very different, looking cars but fundamentally the same vehicle underneath um. They also have 800 volt architecture. They can do crazy, quick charging times as a result, because yeah, obviously the current that its pushing is, is modest, uh but its not like ridiculously massive, as it would be to get that kind of charging power on a 400 volt battery.
Interestingly, tesla are still typically round about the kind of 400 volt mark, but the superchargers are, you know, 250 kilowatts or more these days so um. You know they are using very short cables on the supercharger and those are very wide cables as well, so that they can supply the masses of current that is required so thats. Why? If you take a tesla to a high power dc charger, thats, a universal charger and you might find actually that the charging speed you get on them might not be as much as is advertised if its a charger that says it can do, i mean heres, a Good example um the ones that are commonly used by instavault uh, say that they can do 120 or 125 kilowatts, but quite often the cables on those are limited to 200 amps. So if youre working with a 400 volt battery youre, actually going to top out the 80 kilowatts maximum and thats, where people get a bit confused about whats going on, meanwhile, someone pulls up next to you and the tai can or an ionic 5 and gets the Full 120 125 kilowatts because they have a voltage. That means that theyre not going to be maxing out the current of that cable and hitting up against the voltage limit as either you know they can actually take the full power thats available, because the system voltage is is higher, so whatever that is multiplied by the Current is going to be higher than it would be if it was limited to 400 volts by the cars battery to understand and some and coming into the dv space.
Weve gone very easy weeds with with the discussion of 400 volts versus 800 volts. But there is so many factors along that car cable charger, that the limiting factor that the the smallest denominator is the one that limits everything else. So its people need to understand that and uh. But i appreciate people that are watching. This are probably a bit more in tune with uh with that side of things yeah, dr ewan, do you think that more manufacturers will go this route, or do you think its a its a niche avenue? Some manufacturers will go down and some wont still stick with the 400 volt or where can you see this ending up? Um, i mean were already seeing actually greater than 800 volt systems being proposed, like the lucid air, which i believe goes up to 920, something volts. So you know the trend is very much towards higher voltages. I think the 800 will probably be um. You know fairly standard over the next few years. I cant see 400 volts being retired completely, but um. I certainly think that its going to be a good shout of 800 volts becoming increasingly common, especially because now that uh a more kind of mainstream vehicle, the the ioniq 5 and the ev6 um are doing. You know 800 volts thats going to set the standard when it comes to charging times and so on, and i think that a lot more consumers are going to start demanding that of these vehicles, um so yeah.
I think that, well probably see you know 800 volts becoming fairly commonplace, especially because we were starting to see automotive manufacturers getting used to the safe handling of very high voltage 800 volt dc systems. There is obviously the danger when youre servicing a high voltage traction battery. Is that because its dc current, unlike the ac stuff, that comes out of your wall, if you touch that you get blown away from it but dc, you stick to it until someone shuts off the power or in the case of a battery, someone pulls you off Of the thing with the safety hook, so you know you want to make sure that you know what youre doing with this and um yeah were starting to see more and more vehicle manufacturers and technicians and so on, getting used to safe handling of 800 volt systems. Its safe as long as you follow the correct protocol, so that will probably become standard because it means that you get away with using smaller cables, lighter cables, so theres, less material, theres, less expense and its arguably more sustainable. In that regard as well, and actually we can draw a parallel, admittedly um, not a dc parallel, but an ac um. Parallel to this, if you look at uh the the national grid, if you look at big transmission lines, um, you know the the 400 kilovolt systems that go up and down mainland britain, for example, and the reason that they are such high voltage in comparison to what Comes out your wall is because you can translate, you can transfer a lot more power with a lot less current and therefore lighter cables, less losses as well um.
Otherwise everything would be 220 to 30 volts and it would be massive massive cables and thered be huge losses and it just wouldnt be worth it so yeah um, basically the higher the voltage that you go to, then you know generally the more efficient and arguably lightweight That these things become so yeah yeah long story – short uh, 800 volts, although ive yet to see um concrete evidence of this trickling down into your kind of um everyday family cars. With the exception of the ioniq 5 and the ev6. I reckon its a massive time and do you see the day where somebody would go into a dealership, a consumer? Knowing the difference saying i need something that charges fast. We think we need it, but anyway, uh and saying: is it 800 versus 400 and understanding the difference behind it, or will it just always be too technical for the consumers, um thats, a really good question? I think that uh, if we look at the difference between, for example, usb2 and usb3 um, you know these. These were devices that could plug into the same socket, and in this case you know you can go to a high power charger and you can plug in a 400 volt car or an 800 volt car on ccs. But one you know makes much better use of that facility than the other one, the other one kind of hits up against one of those limiting factors. Whether people are going to necessarily understand how those limiting factors come about, and it is fairly kind of um, high school science or high school physics when you get into it its, not scary, when you know how, but it does involve being given that bit of education Are the are the car dealerships going to do? The education? Is there stuff that people are going to pick up out of uh ev owners groups more likely that sense, but as evs become mainstream? Is that going to become common knowledge? To be honest, i can see charging networks being the ones who actually do the the biggest bit of kind of awareness and pr on this to try and explain.
Yes, our chargers can do up to 150 kilowatts, but your car will only get say 100 kilowatts, and this is why its nothing wrong. It just happens to be that so yeah i i dont know if it will necessarily become universal knowledge like that, but uh ev owners groups will always be on hand to provide that information. Um theres, certainly quite good engagement, even from fairly new ev drivers, as it does become, the mainstream and theyll always get the answers that they need so yeah. I think it will gradually filter through, but it will still be. You know not niche knowledge, but not necessarily the majority of people who know, which is a shame um, but that said, you know youre still, gon na get a decent charge, speed off of uh a current restricted, uh cable on a supposedly high power charger um. So yeah yeah its not the end of the world but yeah. It will generally be slightly more tech, savvy, certainly, tech, savvy people who are aware of it. If you know the difference between usb 2 and usb 3, and while your usb 3 pen works faster than your usb 2, one, then youll probably get youll be also know about the 400 versus 800 volt thing. Otherwise, maybe not im wont be doing a video on usb 2 versus usb 3, just so people in case you put it into the comments. Thank you very much uh, dr uber turk.
Thank you so much again for your explanations, uh, and for more in depth. Explanations about all things: electric you can go to plug, live tv, live television, ill, put the link on the screen and also in the description but uh. Thank you, doctor, um turk, and hopefully everybody enjoyed the review. Make sure you subscribe to evie review. Ireland hit the like button, leave a comment to let us know what you think 400 versus 800 and remember if you think an eb is for you leave it to me and ill review.