AC and DC chargers have one fundamental difference: how power is converted from AC to DC for the battery.
All electricity from the grid is AC (Alternating Current) but batteries are charged with DC (Direct Current). DC chargers have an onboard converter that handles the conversion rapidly, while AC chargers require the vehicle’s slower onboard charger to handle the conversion.
DC chargers send Direct Current directly to your electric vehicle battery, bypassing the onboard charger in your electric vehicle responsible for converting AC power to DC power for the battery (which is necessary with AC chargers).
In other words, DC chargers take a shortcut.
Additionally, AC chargers are a lot slower than DC charge points because DC chargers are connected directly to the grid. This pumps the DC charger with a higher flow of electricity.
When you plug your electric car in at an AC charger like at home, your vehicle is fed with power from the grid. Grid power is Alternating Current (AC), but your battery is compatible only with Direct Current (DC). The electricity is converted by your vehicle’s onboard charger, and this restricts the potential charge speed with AC.
Most new electric cars today have a 7kW-7.4kW onboard charger, which means you can charge at speeds up to 7kW at home. Some vehicles have 11kW onboard chargers, letting you tap into faster-charging speeds with a 3-phase supply.
You can get 3-phase at home for faster AC chargers, but most domestic consumer units and electrical installations can only muster up 11kW on a 3-phase supply.
Commercial premises can unlock 22kW charge speeds with a 3-phase supply, but those with a single-phase supply may require substantial electrical upgrades.
That’s why you see DC chargers with 350kW+ charging speeds – they are connected to the grid supply directly and can harvest huge power.
At home, you have no such luck, but 7kW chargers are pretty fast.
You can also get an 11kW charger like the Wallbox Pulsar Plus if you upgrade to a 3-phase supply, but for most people, 7kW is enough at home.