Case Study

Shadow EV Charging for Commercial Car Park

CEC Building Underground Car Park, DongGuang, China

April 2021


The owner of the car park wants to install certain quantity of EV chargers for visitors. They wants to go for a pilot test before the complete roll-out of the PSN-EVC system. Data shows that the additional loads from EV charging will cause higher peak loads.

power profile without_EVC

Without EV Charging

power profile with Ev

With EV Charging

PSN-EVC Installation in U/G Car Park

It is found that the peak loads after the services of EV chargers has skyrocketed to a dramatic high level. We then installed the PSN-EVC System to address the problem.

Shadow Power Source

Existing 50A Carpark lighting supply (one phase)

PSN-EVC System Schematic Diagram

EV charging for commercial car park

PSN-EVC System running in the Site

One set of PSN-EVC including a master header box and a charger for each charging bay. the system can be easily expanded to supply totally 12 charging bays when needed.

Link Array of Controller Boxes


1 Master connects with 12 Slaves at most.
Maximum 16 connected Masters control 196 chargers.

Master Header Box collects power data from the main switch outgoing (and incoming) circuits as well as the power drawn by each EV. The controller carries out calculation and decides the charge rate for each charger from a slave controller. Master controller connects, communicates and interacts with another master for optimized and coordinated charging load balancing from a shared power pool.

In this case, 1 Master + 3 Slaves for total 4 Charging bays.

Charging Rate Calculation

(1) If Shadow Power > total EV power required , all EVs are allowed to draw max rate.
(2) If Shadow Power < total EV power, individually reduce the charging rate for each bay to the best optimized level in order to afford all charging bays.



On the first day of operation, it is recorded that a large amount of Shadow Power has been harnessed for EV charging. It enables quick and smart EV charging services in the car park in only 10 days with zero money invested in power upgrade. It helps improve the power consumption profile of the building. The long run result shows that a 90% power utilization rate is achieved. 



$0 money on
Power Upgrade

No upgrade of electrical network and main switch. The total power drawn by EVs is always within the idle capacity of the main circuit. NO money spent on electricity upgrade.

All EVs
get charged

Shadow Power is more than enough for the total charging needs when the 4 EV charging bays are charged at the same time, indeed the most economical way to fulfil EV charging service.


Easily scale to more charging points in an array. Conveniently expand to 12 when more charging bays are needed. No more extra power-side electrical installations are needed for future expansion.

a lot of Cost

Net cost-to-serve per charger at least 30% cheaper than the charger installations cost without Shadow EV Charging. Off-peak electricity tariffs are cheaper, also saving a lot of bill money.


Our EVC Super Load Management System does not tie to any specific charger brands and models. Economical chargers can be used in subsequent replacement / addition.


Harness the Shadow Power from the carpark resulted in a more balanced power profile in which more energy used in leisure hours and less in peak hours, indeed a green EV charging solution.