Daily kWh and peak kW answer different questions.
AETREN · SITE CAPACITY
How much electrical capacity does an EV charging site need?
A useful capacity brief separates energy demand from peak charger power. The answer is rarely 'charger kW × number of bays'.
SHORT ANSWER
Size the concept from energy, time and control—not simple nameplate addition.
Calculate daily EV energy demand, divide it across the available charging window, test realistic simultaneity, and compare that against entered site capacity. Then evaluate whether managed charging can defer or reduce an electrical upgrade.
KEY PROJECT POINTS
What should drive the decision.
These are project inputs, not substitute engineering or automatic product approvals.
Not every charger draws nameplate power at the same time.
Fleet departure deadlines can create real simultaneous peaks.
Managed charging can cap site demand while redistributing energy.
DC charging can create short high-power peaks even with few bays.
Future growth should be designed into switchboard, cabling and communications.
Start with daily energy
Vehicles × average kWh per event gives a better first demand measure than simply multiplying charger ratings.
Convert energy into a charging window
A site with ten overnight hours has a different power problem from the same fleet needing to recharge in two hours.
Apply simultaneity deliberately
Use an explicit concurrent-charging assumption or managed cap. Do not hide diversity inside an unexplained rule of thumb.
Protect expansion
Conduits, switchboard space, networking and load-management architecture can be prepared for future bays even if chargers are staged.
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.
Vehicle count
Average kWh/event
Charging window
Expected simultaneous vehicles
AC/DC charger ratings
Port quantities
Existing electrical capacity
Other site loads
Managed charging cap
Growth allowance
Transformer/switchboard information
Operating priority rules
EVIDENCE BOUNDARY
A concept capacity planner is not an electrical design.
Final maximum demand, protection, cable sizing, fault levels, earthing, metering, transformer and switchboard work must be designed and approved by the appointed local electrical professionals.
FAQ
Questions project teams usually need answered.
Can I add all charger kW ratings together?
That gives a theoretical connected load, not necessarily the managed or coincident site demand.
Can load management avoid a transformer upgrade?
Sometimes. It depends on the actual capacity, energy window, vehicle needs and growth plan.
Does Apollo provide final electrical design?
Apollo provides project-supply planning and equipment information; final local electrical design remains with appointed professionals.