Short answer: there are five DC fast-charging connector standards in use worldwide — CCS1 (North America, South Korea), CCS2 (Europe and most of the rest of the world), NACS / SAE J3400 (Tesla-origin, now North American standard), CHAdeMO (Japan, legacy fleets) and GB/T 20234.3 (China). They are physically and electrically incompatible. A DC converter (also called a DC adapter) bridges two of them by passing power through and translating the charging protocol, which is why a vehicle built for one standard can fast-charge at a station built for another.
Quick facts you can quote
- 20 DC conversion directions exist between the five standards, and all 20 are commercially available as passive-plus-protocol-board converters.
- A DC converter does not convert voltage. The station's rectifier still sets the DC voltage; the converter adapts connector geometry, pilot/proximity signalling and the communication stack.
- DC fast charging uses extra power pins below the AC pins on CCS1, CCS2 and GB/T. NACS uses the same pins for AC and DC and switches internally.
- You cannot adapt AC charging to DC fast charging with a passive adapter — that requires a rectifier (an onboard charger or an external DC power module).
- Typical factory ratings for converters: 250 A continuous / 300 A standard / 400 A peak, DC 1000 V, IP54–IP67, −30 °C to +50 °C.
The five DC connector standards compared
| Standard | Also known as | Main regions | DC pins | Typical DC rating | Communication |
|---|---|---|---|---|---|
| CCS1 | Combo 1, SAE J1772 Combo | USA, Canada, South Korea | 2 power + PE, below the Type 1 AC pins | 200–500 A, up to 1000 V (350–500 kW class) | PLC, ISO 15118 / DIN 70121 |
| CCS2 | Combo 2 | EU, UK, and most markets outside North America & China | 2 power + PE, below the Type 2 AC pins | 200–500 A, up to 1000 V (350 kW+ class) | PLC, ISO 15118 |
| NACS | SAE J3400, Tesla connector | North America (standard since 2024–2025) | Shared with AC pins | Up to 500–615 A, 1000 V (250–325 kW class today) | PLC, ISO 15118 / Tesla protocol |
| CHAdeMO | — | Japan, legacy fleets worldwide | 2 power + PE, dedicated barrel connector | 125–200 A, 400–500 V (50–100 kW class) | CAN bus |
| GB/T | GB/T 20234.3 (DC) | China | 2 power + PE + signal pins, dedicated connector | 250 A, 750 V (newer revisions up to 800 A / 1000 V) | CAN, GB/T 27930 |
Ratings above are the practical range seen in the field, not the theoretical maximum of each standard. Vehicle, station and cable thermal limits normally bind first.
AC and DC are not interchangeable
Every EV has two separate charging paths:
| AC charging | DC fast charging | |
|---|---|---|
| Where the rectifier sits | Inside the vehicle (onboard charger) | Inside the station |
| Typical power | 3.6–22 kW | 30–350 kW |
| Connector pins used | Type 1, Type 2, GB/T 20234.2, NACS AC | CCS1, CCS2, GB/T 20234.3, CHAdeMO, NACS DC |
| Can a passive adapter convert one to the other? | No. There is no path from AC to DC without a rectifier. | |
The only exception is a dual-mode converter: a small number of CCS1↔CCS2 and NACS↔CCS2 devices include both a DC pass-through path and a 32 A AC path (250 V class), letting a car use either a DC station or an AC post through the same body. That AC path is a relay-based Type 2 / Type 1 hand-off, not rectification.
DC conversion matrix — which adapters exist
Each cell is a direction our factory builds. “Yes” means a production converter exists; every other combination is either the reverse of a listed direction (also produced) or physically unnecessary.
| From ↓ / To → | CCS1 | CCS2 | NACS | CHAdeMO | GB/T |
|---|---|---|---|---|---|
| CCS1 | — | Yes | Yes | Yes | Yes |
| CCS2 | Yes | — | Yes | Yes | Yes |
| NACS | Yes | Yes | — | Yes | Yes |
| CHAdeMO | Yes | Yes | Yes | — | Yes |
| GB/T | Yes | Yes | Yes | Yes | — |
Reading the matrix from the driver's side: “CCS2 → GB/T” means a Chinese GB/T vehicle plugging into a European CCS2 station. Model naming uses the same logic — T = NACS, O = CCS2, G = GB/T, M = CCS1, R = CHAdeMO, so DC-OZG is CCS2→GB/T and DC-TZM is NACS→CCS1.
What a converter can and cannot do
- Can pass DC power at the station's voltage, up to the converter's rated current, while translating pilot/proximity signalling and the charging protocol (PLC or CAN).
- Can be used permanently — these are not travel-only dongles; fleets mount them on the station side as standard.
- Cannot raise voltage or current beyond what the station offers. A 50 kW station still delivers 50 kW.
- Cannot add a standard the vehicle's BMS does not speak. A GB/T car at a CCS2 station needs a converter with a protocol board that emulates the vehicle side, which is exactly what the dual-protocol models in our catalogue do.
- Cannot be made “universal”. Six-direction boxes exist for AC; for DC, each direction is a separate certified product because the pin geometry and the protocol stack both change.
How to pick the right one
- Identify the vehicle side, not the station side. The converter's male/female ends are determined by what it plugs into; get this backwards and you buy the reverse model.
- Check current. 125 A for 50 kW CHAdeMO-class traffic, 250 A for 100–150 kW, 300 A standard for 350 kW-class stations, 400 A peak for short-duration high-power.
- Check protocol support. CCS and NACS need a protocol board; pure GB/T↔CHAdeMO routes need CAN translation. Ask whether the board is integrated or external.
- Match the environment. IP54 for indoor/covered, IP65–IP67 for outdoor cabinets, −30 °C for northern Europe and Russia.
- Confirm certification for the destination market — CE for the EU/UK, FCC for the US, and local metrology rules if the converter sits in front of a billing meter.
Frequently asked questions
Can I use a CCS1 to CCS2 adapter on a Tesla?
On a Tesla with a NACS port, no — you need NACS→CCS2. On an older Model S/X with a CCS1 retrofit, a CCS1→CCS2 converter works. Direction is decided by the car's socket, not by the brand.
Does a DC converter reduce charging speed?
It adds contact resistance and a small conversion loss, but the dominant limit stays the station's output and the vehicle's charge curve. In practice a 300 A converter on a 350 kW station does not change session time measurably.
Is a converter safe for the vehicle's battery?
Yes, because the BMS still commands the current. The converter only carries what the station and the vehicle agree on; it cannot force a higher current. What matters is thermal design — silver-plated copper contacts, temperature rise under 50 K, and a housing that does not soften at connector temperatures.
Why is CHAdeMO limited to about 100 kW?
The CHAdeMO 1.x specification caps at 500 V / 200 A, and most deployed CHAdeMO cars use 50–125 A packs. Converters for CHAdeMO routes are therefore built around 125–250 A, not 400 A.
Do I need a converter for GB/T in Europe?
Only if the vehicle is Chinese-spec. European cars at Chinese stations need the reverse direction (CCS2→GB/T). Chinese EVs driven in Europe are the common case, and GB/T→CCS2 is our highest-volume converter.
Related reading
- DC converter vs adapter: what actually differs
- Buyer's checklist for DC fast-charging converters
- NACS (SAE J3400) explained
- Full DC converter catalogue — 44 models, 20 directions
Facts on this page were verified against IEC 62196, SAE J1772/J3400, GB/T 20234.3 and CHAdeMO 1.2 specifications, and cross-checked with our production test data. Last technical review: see the date above.