As charging power rises, so does the current flowing through the cable. Current produces heat, and heat limits how much power a cable can carry safely. At ultra-fast charging levels, the solution is to cool the cable with circulating liquid.
The problem with high current
Power equals voltage multiplied by current. Charging faster means raising one or both. Many vehicles still charge at around 400 volts, so delivering very high power requires currents of several hundred amps. A conventional cable sized to carry that current without overheating would be thick, heavy and very hard for a driver to handle.
How liquid cooling works
In a liquid-cooled cable, a coolant flows through channels running alongside the conductors and up to the connector. A pump and heat exchanger inside the charger remove the heat. Because the heat is carried away continuously, the conductors can be much thinner, keeping the cable light and flexible while carrying far more current.
- Thinner, lighter cable: easier for drivers to handle and plug in.
- Higher sustained power: the charger can hold peak power for longer.
- Temperature monitoring: sensors in the connector reduce power automatically if temperatures rise.
When you need it
| Charging level | Cable type |
|---|---|
| Up to around 150 kW | Usually naturally cooled cables |
| High-power car charging | Liquid-cooled cables are common |
| Megawatt truck charging (MCS) | Liquid cooling is essential |
The exact threshold depends on the charger design and current rating, so check the specifications for each model.
Higher-voltage vehicle platforms reduce the current needed for the same power, but ultra-fast charging for cars and especially trucks will continue to rely on cooled cables.
Maintenance matters
Cooled cables are the most heavily used and most exposed part of a high-power charger. Planned maintenance should include coolant level and condition, checks for leaks, inspection of the connector and cable jacket, and cleaning of filters and heat exchangers. Spare cables should be available, because a damaged cable takes a charger out of service.
How PxT can help
PxT Energies supplies and maintains high-power and megawatt chargers with liquid-cooled cables, and includes cable care in our preventive maintenance programmes.