Every DC fast charger must move conversion heat out of its cabinet, and manufacturers choose one of two ways to do it: air cooling, which pushes air across heatsinks with fans, or liquid cooling, which circulates coolant through cold plates and sheds the heat at a radiator. Neither is simply better. The choice is made once, at design time, and it fixes the parts list, the sealing strategy, the noise character and the service model for the life of the product.
Key Takeaways
- Cooling is chosen at design time and fixes parts, sealing, noise and service for the product’s life.
- Air cooling trades consumables and fan wear for a simple, generic build.
- Liquid cooling trades a pump and a leak path for a sealed bay and stronger heat removal.
- Never assume a model’s cooling method — confirm it, and its service schedule, in writing.
How the Two Approaches Remove Heat
Air-cooled designs draw outside air through filters and across finned heatsinks attached to the power modules, then exhaust it. The heat path is short and the parts are commodity items. Liquid-cooled designs seal the power electronics and pump coolant through plates bolted to the hot components; a radiator — usually still fan-assisted — then passes the heat to the outside air. The liquid approach can also be extended into the charging cable, which is why the highest-power cables are often liquid-cooled.
Side by Side: What Changes in the Build
| Design factor | Air-cooled build | Liquid-cooled build |
|---|---|---|
| Parts list | Fans, filters and heatsinks; few specialised parts | Adds a pump, cold plates, hoses, seals, coolant and a radiator |
| Sealing | The air path must open to the outside, so dust control rests on filters and cabinet design | The electronics bay can be sealed more completely; the liquid loop becomes the leak path to manage |
| Noise | Fans are the dominant sound, and they work harder as load rises | The pump is quiet, but the radiator usually still runs fans |
| Assembly | Simple fit and test; no fluid handling on the line | Filling, leak testing and coolant handling are added to production |
| Field service | Filters and fans are routine, swappable consumables | Coolant, pump and seals join the service schedule; a leak is a failure mode air never has |
| Where the logic points | Cost-sensitive designs where enough air can be moved | Sustained high power in a compact cabinet, where air alone struggles |
The Trade-Offs Behind the Choice
For the manufacturer, the decision is an exchange of risks. Air cooling accepts consumable filters, fan wear and a harder sealing problem, and in return keeps the build simple and the parts generic. Liquid cooling buys a sealed electronics bay and stronger heat removal, and in return accepts a pump, a fluid that must never leak, and extra steps on the production line. Site conditions tilt the balance: dusty sites load air filters quickly, and hot sites make every system work harder, as the guidance on hot-climate EV charging sets out from the operator’s side. The engineering question is not which system is best, but which failure modes the maker would rather manage.
Questions Buyers Should Ask
- Which cooling parts are consumables, and what service intervals does the documentation state for them?
- What does the charger do on a cooling fault — derate, alarm or stop? Ask for the documented behaviour.
- On a liquid design: which coolant, what inspection routine, and who supplies the fill?
- On an air design: which filters, are they standard sizes, and how are they reached for service?
EVDANCE Specifications
EVDANCE’s DC model, the EV-RHDC30K-L, is listed at 22 kW DC with OCPP 1.6J and an IP54 enclosure. The published listing does not state its cooling method, and it should not be assumed: for any model, from any maker, the cooling design and its service schedule are specifications to confirm in writing. The full EVDANCE range is on the products page, and specification questions can be sent through the contact page.
Frequently Asked Questions
Is liquid cooling always the better choice?
No. It earns its complexity at sustained high power or in tight cabinets. At lower power, air cooling is simpler to build and easier to service. The site’s duty cycle should drive the choice.
Does a liquid-cooled charger still make noise?
Usually some. The coolant carries heat to a radiator, and most radiators shed it to air with fans — the sound character differs from an air-cooled cabinet rather than disappearing. If a site is noise-sensitive, ask for the model’s stated noise information.
Which system costs less to maintain?
It depends on the site. Air designs consume filters and fans; liquid designs add coolant and pump service but shield the electronics from dusty air. Compare the documented service schedules, not the brochure claims.
Related Reading
- How Do DC Fast Chargers Work?
- Hot-Climate EV Charging: Protecting Chargers From Desert Heat and Sun
- Why Is DC Fast Charging So Expensive?
- How Fast Is a DC Fast Charger?
