Bingo! That's the same 800v design reference from the Nevera hypercar.

Hyundai and Porsche have stakes in Rimac!

You are not wrong. However voltage play huge role in the high power system, especially a DC system.

for the same 70kW, doubling voltage reducing the current by half.

1) Let's assume perfect power factor of 1.0 for simplicity. P = I^2 * R, high school physic. P = Square of Current multiplied by Resistant.

Use V=IR

70,000W with 400V, current = 175A
70,000W with 800V, current = 87.5A

2) Assume gauge 0 cable (that's very thick 0.855cm in diameter cable on each polarity), the resistance is about 0.0004 ohm per meter at room temperature 25C. Assume a 10m cable, that's 0.004 ohm, round trip = 0.008 ohm.

Use P = I^2 * R

400V, power loss over cable = 175^2 * 0.008 = 245W
800V, power loss over cable = 87.5^2 * 0.008 = 61.25W

You see, significantly less loss over the charging cable wires with 800V.
Furthermore the loss power will dissipate as heat, cause the wire to heat up and increase the wire resistance -> even more loss -> even more heat.

3) Let's not forget the voltage drop over the cable. In the school, on electronics, the current is so small and insignificant, we always assume wire resistance = 0, voltage drop over the wire = 0V.

In high power system, it is different story.

Use V = IR

400V voltage drop over the wire = 175 * 0.008 = 1.4V. Voltage at load end = 398.6V
800V voltage drop over the wire = 87.5 * 0.008 = 0.7V. Voltage at load end = 799.3V

You see wire itself cause voltage drop on the high power system, thus we always have something called remote sensing, where we have high impedance load that run in parallel as the actual application load. Such the the current over the high impedance load is small and negligible, then we can measure the load end voltage drop, and compensate it by increase the source voltage.

So source run slightly higher voltage at source to allow load to actually get 400V, 800V.

4) Lastly, running at 800V system also allow thinner wire due to lower current on the car itself. Thus lower loss + lighter car.

5) So, 70kW at 800V will charge faster than 70kW at 400V due to higher efficiency (provided the the bottleneck is not at battery side, and assume same battery thermal management).

This post has been edited by constant_weight: Apr 7 2022, 08:39 PM

You are right on AC charging that used on-board charger that convert AC to DC. 11kW or lower are all AC. 22kW have both AC and DC variant. Those faster charger eg:. 150kW are all DC.
The DC fast charging don't use on-board charger in the car, it is the car that negotiate max supported charging rate with the charging terminal directly. So that case the limit is not the on-board charger, but the battery type, battery array design, and thermal management.

So far the commercially available mass market EV with 800V are all those have stake in Rimac group. The one that build Rimac Nevera 2000hp+ Hyper EV.
Lotus hyper EV also run 800V, again that's hypercar, not for mass market.

Basically Hyundai Group (Hyundai, Kia, Genesis), Porsche Group (Porsche, VW, Audi) are the 2 mass market brands that have access to mature commercially ready 800V technology.

So 800V are still very uncommon. Even we have 800V charger, very few EV can make use of that. But expect more and more to move to 800V in the future.

That's why I strongly discourage people from getting any low cost urban EV from China.
In China they are in special sub-A segment category, even some of them have B/C segment physical size. The PRC administration is considering banning them on highway/ring road, as they not only have the range problem the slow acceleration after 60km/h and poor brake (long braking distance) also cause traffic jam and endangers other road users.

Those got into the fist fight are owner of these mini/micro EV, like the some Chery or GWM Black/Good Cat. Their common signature is advertise high 400-500km NEDC range, with not further details, and yet only have small 30-50kWh battery.

The proper cars with similar small battery like the Mini EV or MX-30 only get 200km+ range in WLTP.
The proper car with big 70-80kWh+ battery get 400km WLTP. Which translate to real world test of about 500km range in pure city driving, and about 300km range in pure highway driving.

You see who is making up the number?

Being said that, the high end EV will have less of the problem. Same 300-400km road trip higher/premium end EV need only 1 charge, or do not need charge at all. The urban EV is the one that need 2-3 charges, and fight for the chargers. In 5 years, those premium EV expected to get 500-600km WLTP range.

So the micro/mini EV owners fight for chargers, the premium EV owners enjoying the road trip.
In ICE world -> low power city car get better fuel economy
In EV world -> high power premium EV get more range

Looking at the development, the premium EV will forever get more range than the smaller EV. When the technology matured enough that if urban EV can actually do 400km (not the fake advertisement), the premium EV will be doing 800km, 1000km.

This post has been edited by constant_weight: Apr 10 2022, 12:18 PM

Agree. Bigger concern they get complains of brake failures since 2021. Still happening to newer Neta U SUV this year.

It is not about EV or ICE now. It is please ensure the basic safety function is reliable.

Mandarin news unfortunately, can use Google/ChatGPT translate.

https://zhuanlan.zhihu.com/p/599395212

https://news.yiche.com/hao/wenzhang/64198458/

https://auto.sina.cn/zz/hy/2021-10-22/detai...tml?vt=4&pos=25

This post has been edited by constant_weight: May 5 2023, 08:54 AM

This is provided the advertised range is achievable in real world, that is not NEDC/CLTC range. We need to adopt WLTP standard range that is closest to real world practical usage.

Our government should pass a rule that all vehicle be it EV range or ICE fuel economy to be based on WLTP. Car dealer, marketing PR, car reviewers need to adhere to the regulation.

NEDC range is bloated, need to reduce at least 20% to be comparable to WLTP.
Worst case is sometimes review articles quote CLTC range, especially the Wxxxxxxxxxxxxxxxxxxxxcar that has no shame of copying other country works without providing credits.
That is misleading some readers (if not most) that are not aware of different testing standards, they only see the number, put standard in quote also they don't know what is that.

This post has been edited by constant_weight: May 8 2023, 04:29 PM

Bubbles burst spreading to large China EV makers. Caution on China EV brands, do your own research on the company financial health.

WM Motor (Weltmiester 威马) once a top EV seller for 3 consecutive years, been facing financial issue since last year. Closed lots of dealerships, or ghosted dealerships left many owners without service and spare part support. Customers pending car delivery are not allowed to cancel their order. Motor is now seeking opportunities to restart production.
https://www.caixinglobal.com/2023-03-10/wm-...-102006605.html

Levdeo (Letin 雷丁) files for bankruptcy.
https://www.chinapev.com/ev-2/levdeo/chinas...r-making-scams/

WM Motor owner protest outside Hainan Island closed down dealership.


This post has been edited by constant_weight: May 12 2023, 09:42 PM

4.7L/100km hybrid unless always city driving, do a lot of highway also can not reach.

This is PHEV category already.

Good EV battery should last 300k km with proper charge, but high risk with Neta after 5 years probably the company no longer exist. Want to change also no parts.

Stick with BYD, or European EV better future assurance. Specific to this topic about Neta, I'll run away from it like a plague.

https://www.dongchedi.com/article/7231842191562277411

2022 net loss 6.919B CNY
2022 sales volume 152073, average 45.5k loss per car sales
Total loss 11.14B CNY over 3 years


China new coming car makers are still on money spending spree to get market share, whoever run out of cash first will be eliminated.


As a new comer (with lack to technology depth/R&D), Neta is heavily relying on their suppliers, if sales volume is not keeping up, the BOM (build of material) price will be much higher than competitors. Worst case is Neta is facing a lot of quality issue.


Neta claims they use CATL battery, but owner found out it is JEVE (who is this? I never heard of this battery maker) after purchase.


Neta attempt to move up market didn't give promising return. The Neta S launched on July 2022 only sold for 2003 cars in first month. On last month April 2023, the sales only 2237. This is huge gap versus BYD Han and Tesla Model 3.


This post has been edited by constant_weight: May 18 2023, 09:48 AM

Glad that the greatest minds of the industries share the same opinion as me.

Gordon comment about "we now have a whole generation of young people never driven a rear wheel drive car" as an analogy of EV transition stuck me the most.

I rarely complement Tesla, this is a great run.

Much more stable rear end over previous Nordschleife attempt, which was sliding all over the place = kudos to the driver for constant steering correction (sorry for not knowing the driver's name, not like Kevin Estre and Lars Kern of Porsche). Good apex speed, until about 2:30, seems like the tyres grip is dropping from heat.

It should be able to maintain the pace for longer time if Tesla give it a wing, with matching front lip aero balance, to be less abusive on raw tyres rubber grip.

Model S Plaid with Track Package - basically gripper Goodyear Supercar 3R (same category as Pilot Sport Cup2) tires, and monoblock calipers with carbon ceramic rotors.

It's about the rear end stability in the corner. See previous attempt, huge contrast.

Why do we want to buy time? As an environmental hero that pushing EV to everyone, you should be extremely delighted to see reduction of fuel and electricity subsidies.

True environment protector be like if I have to sacrifice GDP and reduce quality of life to protect the environment I will do it.

Don't be hyprocrit. Have you buy your EV yet?

When you buy your EV, I'll give you my apology and give you double thumbs up

Until that, 0 convincing power from all the EV link you cookie cut.

Hypocrit