Here’s a crisp field guide to DC fast-charging, split by car voltage and followed by how payments work in the EU/Sweden right now.

DC basics (applies to everyone)

• Peak kW depends on both voltage and amps. 400 V cars benefit most from high-current (≥500 A) stalls; 800 V cars need chargers that support ~850–1000 V to hit top speeds. Many modern HPCs do 1000 V/500 A (e.g., Alpitronic, Kempower, Tesla V4). (leitnerenergy.it, Kempower, ECOFACTOR)
  
• Charger power may be shared. Some sites dynamically split cabinet power across stalls; if neighbors plug in, your available kW can drop. (Kempower/others publish dynamic power management.) (astsbc.org)
  
• Charging curve > headline kW. Time 10–80 % and whether your car/battery is warm (preconditioning) matter more than a single peak. (Even 300 kW-capable cars taper quickly.) (Home | Lucid Motors)
  
• Connector: In Europe it’s CCS2 for DC (up to 1000 V). (ECOFACTOR, Wikipedia)

If your car is ~400 V architecture (most EVs)

• Target stalls with high current. Look for 500 A liquid-cooled cables; that’s how you squeeze the most from ~400–500 V packs. (Kempower)
  
• Don’t overvalue 350 kW labels. On a 400 V car, 350 kW is rarely achievable; 200–250 kW with 500 A is often the practical ceiling. (Older 50 kW units top out at ~150–500 V/125 A.) (library.e.abb.com)
  
• Watch cabinet sharing. If a hub uses shared cabinets, a “free” adjacent stall can deliver more power than a busy one. (Kempower/Terra docs describe dynamic splits.) (astsbc.org, chargingshop.eu)

If your car is 800 V
– Taycan/e-tron GT, Hyundai Ioniq 5/6, Kia EV6/EV6, Lucid, Lotus, Zeekr etc

• Use true high-voltage HPCs. To hit 230–350 kW peaks you need chargers that support ~920–1000 V (Ionity 350 kW, Tesla V4, Alpitronic/Kempower HPC). (Charged EVs, leitnerenergy.it, ECOFACTOR)
• On 400 V-only DC chargers: Many 800 V cars boost internally (via DC/DC or motor-inverter trick) and still charge fast—often ~120–180 kW—but below their 800 V peak. (Porsche/Kia/Hyundai describe this booster behavior.) (vicorpower.com, Hyundai News, greenfleet.net)
• Real-world tip: A well-sited 150 kW stop can be as quick as a distant 350 kW if your curve/taper and SOC are favorable. (greencarreports.com)

Payment systems (EU & Sweden, 2025)

• Card/tap-to-pay is now mandatory on new fast chargers. Under the EU’s AFIR (in force 13 Apr 2024), newly installed ≥50 kW public chargers must offer ad-hoc payment (payment card/contactless). By 2027, all ≥50 kW chargers must have card readers (retrofit). Pricing must be per kWh (with an optional per-minute occupancy fee) and shown clearly before you start. (electrive.com, Kempower, theicct.org, Mobility and Transport)
  
• Plug & Charge (ISO 15118). If your car and the network support it, you just plug in; authentication & billing run via certificates (Hubject PKI is widely used; Ionity supports PnC). It’s the smoothest option when available. (support.hubject.com, go-e, driivz.com)
  
• Apps/RFID & roaming. You can still pay through e-mobility service providers (eMSPs) like Shell Recharge/Plugsurfing/Tesla App, often with roaming over hubs (Hubject, Gireve). Useful for pricing, availability and receipts. (AMPECO, solidstudio.io)
  
• Tesla Supercharger (EU). Most V3/V4 sites in Europe accept non-Tesla via the Tesla app; V4 hardware supports up to ~1000 V and is rolling out contactless terminals in line with AFIR. (carwow.co.uk, Zapmap, The Verge, ECOFACTOR)
  
• Sweden specifics (examples). Circle K is building large 400 kW hubs (Gothenburg/Järna); networks like Recharge provide card terminals (Apple/Google Pay). Some operators also support Swish for certain sites. Always check the site listing for accepted payments. (Alimentation Couche-Tard Corporate, Charged EVs, Recharge Main, Eways.se)

Quick pro tips

• Arrive low, leave early. Plan to arrive ~10–20 % SOC and unplug around ~80 %—that’s the sweet spot on most curves. (Home | Lucid Motors)
  
• Precondition en route. Use built-in nav to the charger so the pack is hot when you plug in—this protects your peak kW. (Most OEMs document this alongside DC derating behavior.) (Home | Lucid Motors)
  
• Check voltage window. Older “50 kW” units may top out at 500 V, limiting 800 V cars; look for HV variants (e.g., ABB Terra 54HV supports up to 920 V) or modern 300–400 kW gear. (library.e.abb.com, astsbc.org)
  
• Mind cable reach & stall layout. Newer V4 Superchargers and many HPCs have longer cables; park accordingly to avoid blocking other stalls. (The Verge)

If you’re adding payments to public EV chargers in the EU here’s the no-nonsense playbook—what’s required by AFIR and the practical ways to implement it.

What the law (AFIR) requires

• Ad-hoc payments must be possible at every public charger.
  • For ≥50 kW DC: new sites (since 13 Apr 2024) must offer contactless card (EMV tap). By 2027, all ≥50 kW chargers must have a card reader (retrofits ok). Pricing must be shown per kWh (you may add a per-minute occupancy fee) and visible before start.
  
  • For <50 kW (AC/DC): ad-hoc payment is still required, but you can meet it with QR/web checkout or similar—no physical display needed if price is shown electronically before start.
  
• QR codes are acceptable if they link to a secure payment page and remain readable.

Your implementation options (mix & match)

1. On-charger card terminal (per post)
   • Built-in or add-on EMV terminal (tap card/phone). Cleanest for ≥50 kW compliance.
     
2. Central “payment kiosk” for many posts
   • One terminal serving multiple chargers; cuts hardware cost and still AFIR-compliant for ad-hoc. (Example: Virta Payment Kiosk, up to ~100 chargers.)
     
3. QR / web checkout (best for AC <50 kW)
   • Sticker or screen with QR → secure page → pay (Apple/Google Pay, card). Make sure price is shown before charging starts.
     
4. App / RFID / roaming
   • Keep these for subscribers and roaming via OCPI (Plugsurfing/Shell Recharge/etc.), but they’re not a substitute for ad-hoc card at ≥50 kW.
     
5. Plug & Charge (ISO 15118)
   • Best UX where supported; compliments, not replaces, AFIR ad-hoc.

Backend + protocol pieces you’ll need

• Charger ↔ CPO backend: OCPP 1.6/2.0.1.
  
• Roaming & price/POI data: OCPI 2.2.1 (publish locations, tariffs, sessions). There’s now an OCPI “Direct Payment” flow that links EMV terminals to sessions for AFIR ad-hoc.

Payments & security hygiene (so you pass audits)

• Use PCI-approved terminals and, ideally, a PCI P2PE solution to minimize your PCI DSS scope. (PTS-approved terminals with SRED + P2PE reduce burden.)
  
• For QR/web checkouts (card-not-present), ensure PSD2 SCA (3-D Secure etc.) via your PSP.
  
• Show transparent pricing (per kWh, + optional per-minute fee) in the app/kiosk/terminal before charging starts.