Separate installed capacity from controlled peak power
Ten 50 kW ports represent 500 kW of nameplate capacity, but the site does not have to deliver 500 kW at once. Session overlap, vehicle limits, dwell time, and a managed site cap determine the actual charging peak. That distinction can change service-upgrade requirements and demand charges.
Collect vehicle requirements before selecting charger power
- Daily miles or energy required by each vehicle group
- Arrival and required departure times
- Vehicle AC or DC acceptance limits
- Number of ports that must be available simultaneously
- Minimum reserve for unexpected trips or public users
A fleet vehicle parked for ten hours may not need its charger to operate at full power for ten hours. Public fast charging has a different service promise and may require higher power with less scheduling flexibility.
Model the complete site, not the chargers alone
| Input | Question | Useful evidence |
|---|---|---|
| Building load | When does the existing facility peak? | Utility interval data |
| Charging sessions | How much energy and dwell time are available? | Fleet schedule or network export |
| Tariff | Which intervals and seasons are expensive? | Current utility rate sheets |
| Electrical capacity | What can the service and distribution equipment support? | Qualified electrical assessment |
Managed charging is an allocation problem
A site controller can allocate limited power according to departure time, energy need, charger status, building load, and tariff period. A fixed cap is simple, but a dynamic limit that responds to building demand can use available capacity more effectively.
Test the control strategy against difficult operating days, not only averages. Cold weather, late arrivals, high public use, maintenance outages, and unusually high building load can reduce flexibility.
Calculate all-in electricity cost per delivered kWh
Keep electricity cost separate from hardware, construction, maintenance, networking, payment processing, financing, parking, taxes, incentives, and revenue. Low early utilization can make the electricity portion look expensive because demand and fixed costs are spread across fewer sessions.
Frequently asked questions
Do all commercial EV chargers create demand charges?
No. Demand charges depend on the applicable utility tariff and the site's measured peak. Higher-power charging and greater concurrency increase exposure, but managed charging and existing building load shape also matter.
What is charger concurrency?
Concurrency is the share or number of ports drawing power at the same time. Installed nameplate capacity is not always the same as the likely or controlled site peak.
How does low utilization affect charging economics?
A fixed or demand-based cost spread across relatively few delivered kWh raises the all-in electricity cost per kWh. Utilization growth can improve unit economics if it does not create a proportionally larger peak.
Should a business choose the utility rate before installing chargers?
Yes. Compare every eligible rate and EV-specific option before final equipment sizing. Energy prices, demand rules, time windows, and fixed charges can materially change operating cost.