Dwell time matters as much as vehicle count.
AETREN · CHARGING ARCHITECTURE
AC vs DC EV charging for commercial projects.
The correct charger is determined by how much energy each vehicle needs and how long it can stay—not by choosing the highest kW number.
SHORT ANSWER
Use dwell time and energy demand to decide AC, DC or a mixed architecture.
AC charging generally suits longer dwell periods and larger numbers of lower-power bays. DC charging suits shorter dwell, higher daily energy or operationally critical turnaround. Many commercial sites need a mixed architecture plus load management.
KEY PROJECT POINTS
What should drive the decision.
These are project inputs, not substitute engineering or automatic product approvals.
Daily kWh demand is more useful than charger nameplate power alone.
AC can scale to many bays with managed charging.
DC can reduce dwell but raises site power and thermal/service demands.
Fleet duty cycles may justify different architecture from public parking.
Backend/OCPP, payment and access model affect the operating design.
COMPARISON
Use-case fit before product preference.
The table is deliberately directional. Exact configurations still require project and evidence review.
| Pathway | Best fit | Watch closely |
|---|---|---|
| Commercial AC | Hotels, workplaces, apartments, long-stay parking and overnight fleet charging. | Available dwell time, connector compatibility, load diversity and bay turnover. |
| Commercial DC | Fleet turnaround, highway/commercial stops, high-energy vehicles and time-critical charging. | Transformer/switchboard capacity, thermal derating, demand charges and serviceability. |
| Mixed AC + DC | Sites serving both long-dwell users and priority/rapid-turnover charging. | Load allocation, backend control, user rules and future expansion. |
Translate use into kWh
Estimate energy per charging event and daily charging events before picking charger power. A 22 kW AC charger does not deliver 22 kW continuously to every vehicle.
Match power to dwell window
The same 30 kWh energy requirement can be served by a lower-power charger over many hours or a higher-power charger over a short operational window.
Check site capacity early
Main supply, transformer, switchboard, diversity and other building loads can control the practical architecture more than parking geometry.
Plan the operating layer
OCPP/backend, payment, RFID/app access, fleet priority, tariffs and uptime monitoring should be defined before equipment release.
PROJECT INPUTS
What to have ready before asking for the exact system.
A stronger brief shortens the gap between product interest and a useful technical/commercial response.
Site type
Vehicle mix
Charging events/day
Average kWh/event
Dwell window
Simultaneous vehicles
Available EV electrical capacity
AC/DC port counts
Load-management requirement
Backend/OCPP/payment model
Climate/exposure
Future growth
EVIDENCE BOUNDARY
AC/DC category choice does not prove exact charger compliance.
Verify IEC 61851, EMC, destination electrical approvals, connector configuration, OCPP support, metering/payment and environmental evidence against the exact charger model and destination.
FAQ
Questions project teams usually need answered.
Is DC charging always better than AC?
No. Higher power can be unnecessary or uneconomic where vehicles have long dwell periods and modest daily energy requirements.
Can a site mix AC and DC chargers?
Yes. Mixed architectures are often useful where long-dwell parking and priority/rapid-turnaround users share one site.
Does charger nameplate power equal vehicle charging power?
Not always. Vehicle limits, battery state, temperature and charger control can reduce actual power.