Electric cars are gradually becoming more common, and they bring with them a whole new set of specifications that matter. One of the most important is range, but another key factor that influences the overall experience of owning an electric vehicle (EV) is voltage.
You’ll often see car manufacturers highlighting their vehicle’s battery voltage in their marketing. For example, Hyundai boasts about the 800-volt battery in their EV6, which is twice the voltage of the 400V battery in the Tesla Model Y. But what does this higher voltage actually mean for you as a driver? Let’s break it down.
When you connect a charger to your EV, electricity flows from the charger to your car’s battery. This flow can be measured in terms of watts, volts, and amps, each representing a different aspect of what’s happening. Understanding voltage is pretty straightforward if you think of electricity like water and voltage like water pressure. In this analogy, voltage is the pressure applied in the pipes, pushing the water through faster. Similarly, the higher the voltage in your charging system, the more energy is pushed through with less current.
Continuing with the water analogy, amps (or current) would be like the size of the pipe. To move a lot of water, you can either increase the pressure (voltage) or make the pipe bigger (increase the current). Charging speed is mainly determined by voltage and current. With higher voltage, you need less current, and with lower voltage, you need more current.
This is where watts come into play, as they represent overall power. Watts are calculated by multiplying voltage by amperage. For instance, 120 volts at 1 amp equals 120 watts. This number indicates the power being transferred at any moment. Your EV’s battery capacity is measured in watt-hours (Wh), which is a measure of how much power can be supplied in an hour. A kilowatt-hour (kWh) is 1,000 watt-hours. So, if your car has a 100kWh battery, it can supply 100kW (100,000 watts) of electricity for an hour.
In simpler terms: to charge your car faster, you need either more voltage or more current. However, increasing current leads to more energy loss and heat, complicating faster charging. Hence, the better way to speed up charging is by increasing the voltage.
Higher-voltage systems, like 800V, have another advantage: they reduce energy consumption by lowering energy loss. This means more of the power goes to the motor instead of being lost as heat, and the battery itself is better preserved.
So, why don’t all electric cars use high-voltage systems? The main reason is cost. Implementing a high-voltage system requires manufacturers to redesign the car’s circuits and components to ensure safety and reliability, which is expensive. Additionally, the components themselves are pricier. Therefore, the primary reason not every EV has an 800V battery is money.
Currently, an 800V system is considered “high voltage,” but there could be even higher voltages in the future. Companies like Lucid, renowned for their range and charging speed, already use 900V battery packs. Some notable 800V cars include the Kia EV6, Hyundai Ioniq 5, and Hyundai Ioniq 6. These vehicles offer high-voltage systems at relatively reasonable prices, at least for EVs. They can charge at 350kW, the fastest EV charging speed commonly available now.
Other manufacturers like Porsche and Audi also utilize high-voltage systems, offering cars capable of charging at 350kW. More models are likely to follow. For instance, the upcoming Kia EV9 will feature an 800V architecture, although some of Kia’s lower-cost future models will continue to use 400V systems. It’s expected that 400V EVs will gradually become obsolete over the next few years.
However, some vehicles, like the Hummer EV, use innovative solutions to achieve quick charging speeds with a 400V system. The Hummer EV has a dual-layer battery, each layer charging semi-independently, allowing it to achieve 350kW charging speeds typically reserved for 800V cars.
Although few cars utilize such tricks currently, it’s likely that manufacturers will transition to full 800V architectures over time due to the clear advantages they offer. It might take a while before all EVs adopt these high-voltage systems, but given the importance of faster charging speeds, it’s hoped that this shift happens sooner rather than later.