Soleil EV Weekly Gazette

400V vs 800V EV's: Why Does It Matter?

Virtually every week now a press releases comes through announcing another EV Launch. There are perhaps 30 electric vehicles available in Canada now, but this should double in one year's time. 

State-of-the-art in EV design uses 800V architecture which allows charging at over 150kW DC. Only the VW/Audi group's PPE platform (Porsche Taycan and Audi E Tron GT) and the Hyundai/Kia E-GMP variants (Kia EV6 and Hyundai Ionic 5) are so equipped. Everything else is 400V, and limited to 125kW-150kW DC fast charging.

 If an EV uses 20 kWh/100km and needs a 300km 're-fill' with a 60kWh charge, this would mean the difference between about 30 minutes at the charge station for a 400V vehicle and half of that for an 800V - provided you are at a charging station that supports 800V charging. 

Bi-directional charging - allowing 120V AC electrical accessories to be run off the EV's battery - is present in the Hyundai/Kia E-GMP with 3.6kW of power output. A typical 120V 15Amp household plug provides 1.4kW for comparison. 

The Ford F150 Lightning offers bi-directional charging up to 9.6kW, which is enough to power a house in the event of a power outage. A household stove or dryer will use about 3kW each to run. 

The VW/Audi Group's EV's, including the PPE platform for the Porsches and expensive Audis, and the MEB platform for the more affordable offerings (ID.3, ID.4, Q4 e Tron) will offer bi-directional charging next year, according to VW.

For home charging, Porsche and Ford offer 19.2kW AC chargers which will use a 100Amp home breaker and 240V plug. Everything else is between 7kW and 11kW for home charging. 

So if an EV were to have the best of everything available today, it would have 800V architecture for the fastest DC charging, bi-directional charging at 9.6kW to be able to power a household in the event of a blackout, and a 19.2kW AC home charger that would offer a 1:1 ratio between driving and charging. This doesn't exist in one vehicle at the moment, but perhaps the Hyundai/Kia E-GMP comes closest, and the Porsche will tick all the boxes if/when bi-directional charging is introduced. 

The vehicles that could benefit from 800V the most are the trucks with the largest battery packs, but the F150 Lightning, Rivian and GMC Hummers are being introduced with 400V. Rivian and GM say that their vehicles are designed for a future upgrade, but considering this means component changes, it is unlikely that this will be retrofittable. 

The reason for using 400V, when the higher voltage is clearly superior, is of course cost. The EV industry has standardized 400V components, and bespoke pieces are expensive. That said, Hyundai/Kia managed to do it, no doubt though a big commitment to volume, perhaps with the help of Delphi. Keep in mind that the vehicle manufacturers make very few of the electric components themselves, farming most of the pieces out to suppliers. 

“The reason for that [400V] is the supply base of all the high-voltage ‘stuff’ in the vehicle, the electric compressor, DC-DC converter, is all built up around a sub-450 world,” he said. “As the world builds out 800-volt capability, everything’s architected so very quickly we can switch over to 800 volts."

-Robert Scaringe, CEO Rivian

Top: Hyundai's Genisis X Concept car best looking of the Korean efforts - let's see how close the production version is to this design. Those rear fenders look like they came off a Porsche 934!

Kia EV6 (top) and sister car Hyundai Ionic 5 (above) set to deliver their first North American cars in early 2022. First 1,500 orders for the Kia get an Apple Watch. The E-GMP platform is impressive with 800V architecture, 3.6kW bi-directional charging, 250kW DC and 11kW AC charging.

BMW launches it's first volume EV's - the iX and i4. 80kWh battery packs, 400V architecture, but no mention of bi-directional charging. They do have an new grill design though...

It doesn't look like much but this Delphi 800V SiC Silicon Carbide AC/DC inverter can half the time it takes to charge an EV. The company recently secured a landmark $2.7-billion order for volume production of this technology over eight years with a premier global OEM. That's probably over 1M units so somebody is serious about 800V.

We can give Porsche some credit for developing 800V architecture with their 919 Hybrid Le Mans car. When they decided to field a top-tier LMP1 racing car to compete in the World Endurance Championship for the 2014 season, including the famous Le Mans 24 race, they had to design their car not only to be the fastest - but the fastest using a given amount of energy.

Various classifications were available to manufacturers that allowed different levels of hybridization with an inverse quantity of allowable fuel burned per lap. Porsche choose the top 8MJ category which meant the smallest fuel allocation and the greatest opportunity for energy recuperation. Other competitors used supercapacitor electrical storage (Toyota) or a Williams F1 type mechanical flywheel (Audi), but Porsche used a li-Ion battery pack along with a unique generator fed off an exhaust-driven turbine.

An 1000kg LMP1 Le Mans car will brake from 335km/hr on the Mulsanne straight to 80km/hr for the chicane in around 5 seconds, meaning there is a tremendous amount of kinetic energy that needs to be captured in a very short period of time. If you remember the formula W = A x V, and increased amount of power can be transmitted either by increasing the Amps through thicker cables or by increasing the Volts. As increasing the size of the cabling adds weight and heat, the only way to practically capture this energy was through a high voltage system. This had to be developed from scratch.

The Porsche 919 Hybrid won Le Mans in 2015, 2016, and 2017 taking the World Endurance Sportscar championship each year as well. The 800V electrical architecture was adopted for Porsche's first electric car, the Taycan.