I’m asked a variation of this question at least three times a week: “Should I opt for DC or AC fast chargers for my project?” And every time, my answer is the same: it depends on what your customers do with their cars whilst they’re at your site. That might sound like a non-answer. It isn’t. Let me explain.
The Basic Difference — And Why It Actually Matters
The difference between AC and DC charging isn’t just about speed. It’s about where the current conversion takes place. With AC charging, the charger sends alternating current directly into the vehicle. The car’s on-board converter then transforms this into direct current to power the battery. The charging speed is limited by the on-board charger, not by your equipment. Most electric passenger cars are equipped with on-board chargers rated between 7 kW and 22 kW.
With DC fast charging, the conversion takes place inside the charging station itself. The charger supplies direct current directly to the battery, completely bypassing the vehicle’s on-board charger. This is why DC chargers can reach power ratings of 40 kW, 120 kW or 240 kW — speeds no on-board charger could ever process.
Why does this matter for commercial buyers? Because it determines how long your customers — or your fleet vehicles — are physically on your site.
Charging Speed: The Numbers That Actually Count
A typical EV battery today has a capacity of around 60 to 80 kWh. Let’s use 75 kWh as a baseline.
- 7 kW AC charger: Full charge ~10–11 hours. Add 100 km of range: ~2.5 hours.
- 22 kW AC charger: Full charge ~3.5–4 hours. Add 100 km: ~45 minutes.
- 60 kW DC fast charger: Full charge ~75–90 minutes. Add 100 km: ~15 minutes.
- 120 kW DC fast charger: Full charge ~40–50 minutes. Add 100 km: ~8 minutes.
- 240 kW DC fast charger: Full charge ~20–25 minutes. Add 100 km: ~4 minutes.
One thing worth flagging: these numbers assume the vehicle can accept the full rated power. Many passenger EVs cap DC acceptance at 50–150 kW even if the charger can deliver more. For fleet operators running commercial vehicles — trucks, vans, buses — acceptance rates are often higher, which is where 240 kW+ equipment starts making serious financial sense.
The Real Question: What Are Your Customers Doing?
This is what I ask every buyer before recommending anything.
Hotel, office, residential complex: Customers park for 4–8 hours minimum. They don’t care about speed — they care about whether it works. A 7 kW AC charger gets them from 20% to 90% overnight. A 22 kW unit does the same in under 3 hours. In this scenario, DC fast chargers are almost certainly overkill — you’d be spending 5–8x more to solve a problem that doesn’t exist.
Retail mall, supermarket, restaurant: Customers dwell 45 minutes to 2 hours. A 22 kW AC charger adds 30–50 km during that window — useful, but not transformative. A 60–120 kW DC fast charger is a different story. A customer who arrives at 15% can leave at 70–80% after a 90-minute lunch. In markets where EV adoption is above 10–15%, fast charging is increasingly a footfall driver, not just a perk.
Highway service station, dedicated charging hub: Speed is the only requirement. Customers are stopping specifically to charge. Dwell time is set by the charger, not your other amenities. Anything under 60 kW creates queues. The market standard for highway charging is moving toward 150–350 kW per gun.
Fleet depot — logistics, delivery, municipal: A completely different calculation. 20 delivery vans returning at 6 pm, each needing 40 kWh, ready by 10 pm — that’s 800 kWh in 4 hours. With 7 kW AC chargers you’d need 28 charging points. With 40 kW DC units you’d need 5. The capital cost comparison is not always what you’d expect.
Cost Comparison: Equipment, Installation, and TCO
Equipment cost (factory-to-buyer ranges):
- 7 kW AC charger: $800–$2,500
- 22 kW AC charger: $2,000–$6,000
- 60 kW DC fast charger: $8,000–$18,000
- 120 kW DC fast charger: $18,000–$35,000
- 240 kW DC fast charger: $40,000–$80,000
If someone quotes you a 120 kW DC charger at $7,000, either the certifications are questionable, the components are substandard, or both.
Installation cost: AC at 7–22 kW needs a 32A–63A dedicated circuit — expect $500–$2,000 per point. DC fast charging at 60 kW+ requires three-phase high-voltage supply, cable sizing, switchgear, and often transformer upgrades. For a 120 kW installation from scratch, civil and electrical works can run $15,000–$50,000 on top of equipment.
5-year TCO comparison for a 10-point retail parking lot:
- 10 × 22 kW AC chargers: ~$60,000 total (equipment + installation + maintenance)
- 4 × 120 kW DC chargers (serving ~10 vehicles via load sharing): ~$175,000 total
The DC option costs roughly 3x more. But if those chargers are generating revenue, the ROI picture changes significantly.
Revenue and ROI: Where DC Starts to Win
AC charging is almost always a cost center. DC fast charging can be a revenue center.
At a workplace or hotel, you’re providing a service. Unless you charge a premium membership fee, you’re recovering cost through goodwill and retention — indirect revenue at best.
At a retail or highway location, you charge per kWh or per minute. A 120 kW charger delivering 80 kW average at $0.35/kWh generates roughly $28/hour. At 60% utilization across 16 hours: ~$270/day, ~$98,000/year per charger. With equipment plus installation at $80,000–$100,000, payback is under 18 months in a high-traffic location.
That math doesn’t work for AC chargers. The session is too long, the revenue per hour too low.
Grid Capacity: The Constraint Nobody Mentions Until It’s Too Late
The practical limit for AC charging without major grid upgrades is 10–20 units at 22 kW on a standard commercial connection. For DC, a single 120 kW charger draws 130–140 kW at peak. Three simultaneously could overload an entire commercial building’s electrical supply.
The solution is dynamic load management — software that distributes available grid capacity across active sessions in real time. All of Hongjiali’s DC chargers support OCPP-based load management, so the system automatically limits individual session power to stay within your contracted grid limit. In practice, you can deploy more chargers than your peak capacity would suggest, because not all vehicles charge at maximum rate simultaneously.
For very large deployments, the emerging model combines solar panels, battery storage, and DC charging in a self-contained microgrid — reducing grid dependency and enabling charging infrastructure where upgrading the grid connection is prohibitively expensive. We call this a solar-storage-charging integrated station, and it’s one of Hongjiali’s fastest-growing product categories.
My Actual Recommendation Framework
Go AC (7–22 kW) if:
- Average dwell time is 3+ hours (hotels, offices, residential, hospitals)
- Budget is the primary constraint and revenue generation is not the goal
- Grid capacity is limited and upgrade costs are prohibitive
- You need to deploy 20+ points cost-effectively
Go DC (40–120 kW) if:
- Average dwell time is 20 minutes to 2 hours (retail, restaurants, entertainment)
- You want to generate revenue from charging fees
- You’re serving a fleet with known charging windows and high daily mileage
- Location is highway-adjacent or a dedicated charging destination
Go DC 150 kW+ if:
- You’re building a highway service station or dedicated fast charging hub
- You’re operating heavy commercial vehicles (trucks, buses)
- You need the fastest possible fleet turnaround
Go mixed AC + DC if:
- You have a retail site with both short-visit and long-dwell customers
- You want to offer tiered service: free slow charging, paid fast charging
- You’re optimising for simultaneous utilisation across different user types
What Hongjiali Offers Across Both Categories
We manufacture both AC and DC charging equipment across the full commercial range:
- AC chargers: 7 kW single-phase to 22 kW three-phase. Wall-mount and pedestal. OCPP 1.6J compatible.
- DC fast chargers: 40 kW to 480 kW. Single to four guns. Floor-standing, wall-mount, and cabinet configurations.
- V2G bidirectional chargers: 30 kW to 240 kW. Vehicle-to-grid export for grid services or building load shifting.
- Solar-storage-charging integrated stations: Combined PV, battery storage, and DC charging in one system.
All products carry CE, TÜV, SAA, CB, or ETL certification depending on target market. We ship to 100+ countries and offer OEM/ODM from 5 units.
If you’re sizing a project and not sure which configuration fits, send us your site details — daily vehicle count, average dwell time, grid connection capacity — and we’ll run the numbers for you. No commitment required.
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