Automobile manufacturers love to emphasize “800V”, but the charging piles display “kW”.
This year, the National Day holiday was connected with the Mid – Autumn Festival, forming a super holiday as long as eight days. The long enough time, combined with the free toll on highways, undoubtedly provided an excellent opportunity to plan a comfortable self – driving tour.
When it comes to self – driving tours, the advantage of new energy vehicles in energy consumption expenditure is quite obvious. “I recently bought a mid – sized SUV from a certain domestic brand. On weekdays, when driving on a mixed road condition of urban roads and elevated roads for a round – trip of seventy or eighty kilometers. With the kinetic energy recovery set to the’standard’ mode, its power consumption per 100 kilometers is stable at about 14 kW·h.”

This vehicle is equipped with a battery pack with a capacity of 78 kW·h. Even conservatively calculated with an actual pure – high – speed range achievement rate of 80%, it can easily achieve a pure – electric range of about 450 kilometers when fully charged. If calculated according to the current average electricity price of 1 yuan per kilowatt – hour at fast – charging stations, the travel cost per 100 kilometers is only about 17 yuan.
The advantage of new energy vehicles in energy consumption expenditure is really remarkable, but an efficient energy – replenishment system is also essential for a wonderful journey. When we are “charging” our cars at service areas or charging stations, an interesting phenomenon emerges: when promoting their products, automobile manufacturers are keen to emphasize concepts such as “800V high – voltage platform” or “4C ultra – fast charging”, but the most eye – catching number on the screen of the charging pile is the charging power in “kW”.
To clarify this seemingly contradictory promotion logic, we first need to review a basic knowledge of junior high school physics:
Charging power = charging voltage × charging current (P = UI).
This simple formula tells us a simple truth: what determines the charging speed is the power (W), not the individual voltage (V) or current (I). Just like when we charge our mobile phones, we care about whether the charger is 18W or 65W, rather than its output voltage in volts.
After all, the unit of measurement for battery capacity is kilowatt – hour (kW·h). It is the most intuitive to calculate the charging time with power: for a 100 kW·h battery, theoretically, it can be fully charged in 30 minutes with a 200kW charging pile. This calculation method can be easily understood even by consumers who are not very sensitive to physics.
Since this is the case, why do automobile manufacturers love to promote “800V”?
It should be noted that the promotion strategies of automobile manufacturers are often the result of the interweaving of multiple factors such as technology, marketing, and consumer psychology. The popularity of the concept of “800V” is a typical manifestation of this complex logic.
From a technical perspective, we know the formula of charging power = charging voltage × charging current (P = UI), and understand that the ways to improve charging efficiency are nothing more than increasing the voltage (U) or increasing the current (I), or both.
However, in engineering practice, the challenges and costs of these two paths are completely different. Here, another key physical formula needs to be introduced – Joule’s law:
Heat generation power = current² × resistance (P = I²×R).
This formula reveals a core problem: the heat generated during the power transmission and charging process has nothing to do with the voltage, but is directly proportional to the square of the current. This means that if we blindly increase the current in pursuit of high power, the heat generation of the entire charging system, including the charging pile, cables, vehicle interface, and battery, will increase exponentially.
This will not only lead to a large amount of energy being wasted in the form of heat, but also pose a huge challenge to the heat – dissipation design of the system, and even cause serious safety hazards.
In contrast, increasing the voltage is a more “elegant” technical route. For example, to achieve a charging power of 400kW, we can choose the “400V × 1000A” solution or the “800V × 500A” solution. The power of the latter is exactly the same as that of the former, but since the current is halved, its heat generation power under the same resistance is only one – quarter of the former.
Therefore, from a technical perspective, when achieving the same high – power charging, the high – voltage platform can use thinner cables (reducing costs and weight), reduce heat generation, and improve charging efficiency. Voltage (U), as a variable that automobile manufacturers have greater independent control over when designing the three – electric system, its increase directly reflects the technological breakthroughs of automobile manufacturers in electrical architecture, power management, and core components, and naturally becomes an excellent window to showcase technological strength.
And showing technological strength through voltage is also a marketing trend.
In the early stage of the development of China’s new energy vehicle industry, the mainstream products in the market generally used the national – standard AC slow – charging, with a relatively low charging voltage. At that time, Tesla established a benchmark image of “fast charging” globally with its unique 380V DC fast – charging technology and self – built super – charging network. Tesla’s voltage platform became synonymous with “fast” at that time.
In order to achieve an edge in the core battlefield of “energy – replenishment experience”, “800V” emerged as the synonym for the next – generation high – voltage platform. This number not only doubles in value but also carries a marketing narrative: when others are still using the previous – generation technology, we have entered the “second – generation electric vehicle experience”.

“800V” cleverly condenses the complex engineering advantages of “lower heat generation, higher efficiency, and faster charging” into a simple, resounding, and technological – sounding label, forming a powerful statement to benchmark or even surpass the predecessors (such as Tesla).
From “slow charging” to “fast charging” and then to “800V”, such a promotion path is indeed more consumer – friendly. Even without understanding the underlying physical principles and marketing trends, consumers can easily understand the sense of technological iteration through the intuition of “the larger the number, the better”. However, this simplification also leaves room for “word games”.
First of all, the so – called “800V high – voltage platform” does not mean that the vehicle can actually reach a charging voltage of 800V. There is an unwritten rule in the industry: as long as the voltage exceeds 400V, it can be called an “800V high – voltage platform”.

Taking some popular models in the market as an example, the XPeng G9, which was one of the first to propose 800V high – voltage fast charging, has a rated voltage of 569V for its 2025 long – range Max model on sale; the Changan Avatr 11 2025 Max pure – electric version has a rated voltage of 572V; the two battery packs of different capacities of the Porsche Taycan have rated voltages of 613V and 723V respectively. It can be seen that the rated voltages of these “800V high – voltage platform” models are still quite far from 800V.
Even if the vehicle’s battery system supports 800V, it can be divided into “full – range 800V” and “partial 800V”. “Partial 800V” may only mean that the battery and charging system support high voltage, but the core components such as the motor, air – conditioning compressor, and on – board charger (OBC) in the vehicle still operate at the traditional 400V voltage, and need to be stepped down through an expensive DC/DC converter. This not only increases the cost and complexity but also causes energy loss during the voltage conversion process.

“Full – range 800V” means that all high – voltage components from the battery to the electric drive, thermal management, and charging operate under the 800V architecture, which is a real generational innovation. The key to achieving “full – range 800V” lies in a third – generation semiconductor material called “silicon carbide” (SiC).
Compared with traditional silicon (Si) – based semiconductors (such as IGBT), silicon carbide (SiC) has higher voltage – withstand capability, lower on – resistance, and faster switching frequency. This means that power electronic components such as inverters and converters made of SiC devices can operate at higher voltages and temperatures, while being smaller in size, lighter in weight, and more efficient.
It is the maturity and application of SiC technology that have paved the way for the popularization of the “full – range 800V” architecture, allowing the advantages of the high – voltage platform to be fully utilized.
Automobile manufacturers may not be concerned about the debate over “true or false 800V”, but policies are guiding the industry towards a mature and orderly direction.

In June this year, the General Office of the National Development and Reform Commission and other departments jointly issued the “Notice on Promoting the Scientific Planning and Construction of High – Power Charging Facilities”, which is the first special document issued by national ministries and commissions regarding high – power charging facilities.
In the document, the statement of moderately advancing the layout of high – power charging facilities in the notice has undoubtedly attracted much attention. By the end of 2027, the number of high – power charging piles nationwide should exceed 100,000. This means that in the next few years, we will witness a major upgrade of charging infrastructure.
What exactly is the “high – power” mentioned in the notice? Although the document does not give a clear numerical definition, the industry generally believes that the charging power of high – power charging facilities is not less than 480kW, and can reach up to 800kW or even higher. At this power level, a vehicle equipped with a 100 kW·h battery can theoretically be charged to 80% in 10 – 15 minutes.
This standard – setting idea centered on power reflects the new trend of industrial development: whether it is the “800V platform” or “dual – gun charging”, it ultimately boils down to the core indicator of charging power. Directly indicating the wattage is not only more scientific and accurate but also makes consumers’ choices clearer.
From the perspective of technological development, high – power charging is promoting the upgrading of the entire industrial chain. Charging pile manufacturers are researching and developing liquid – cooled charging guns and intelligent power – distribution systems; power grid enterprises are upgrading power – distribution facilities and exploring the integration of energy storage and charging stations; automobile manufacturers are optimizing battery management systems to improve the charging tolerance of vehicles. This coordinated evolution of the entire industrial chain is a sign of the maturity of the new energy vehicle industry.
More importantly, the unification of power standards is conducive to the protection of consumers’ rights and interests.
When charging stations clearly mark “480kW” instead of the vague “super – fast charging”, and when automobile manufacturers promote “maximum charging power of 350kW” instead of just the “800V platform”, consumers can have a clearer understanding of product performance and make rational choices. This improvement in transparency is crucial for establishing a healthy market order.
Technological progress is always worthy of praise, and the 800V high – voltage platform does represent an important breakthrough in electric vehicle technology. However, what consumers need is not only cool technical terms but also real – world usage experiences. As the industry matures and standards improve, it is believed that in the future, we will no longer see various confusing technical parameters but simple and intuitive performance indicators.
This article is from the WeChat public account “Zhi Xing Jia Dao”, author: Pacific J2 Station. Republished by 36Kr with permission.
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