EV Fleet Charging: Load Balancing vs. Grid Upgrades

As Thailand's EV adoption accelerates, logistics companies, factories and commercial properties are all facing the same question: how do we charge 20, 50 or 100 vehicles without blowing our electrical infrastructure budget?

The instinctive answer — upgrade the transformer, add a new main distribution board, pull heavier cable — is also the most expensive one. Before committing to a six-figure infrastructure project, it is worth understanding what smart load balancing can do with the capacity you already have.

How load balancing works

Smart EV chargers communicate with a central controller that monitors total site load in real time. When demand from production equipment spikes, the controller throttles EV charging rates proportionally across all connected vehicles. When the factory floor is quiet — overnight, weekends — the chargers ramp up to full power. This dynamic allocation ensures the site never exceeds its contracted capacity.

AC vs DC charging for fleets

AC chargers (7–22 kW) are sufficient for vehicles parked overnight for 8+ hours. DC fast chargers (60–120 kW) are necessary for quick turnaround operations but place far greater demands on the electrical infrastructure. A mixed deployment — a handful of DC units for high-priority vehicles and AC chargers for the rest — often strikes the right balance.

Real-world savings

One logistics operator in Bangkok initially budgeted 3.2 million THB for a transformer upgrade to support 30 chargers. After deploying a load-balanced charging system with dynamic power allocation, the existing 800 kVA transformer handled the full fleet with headroom to spare — saving over 2 million THB in avoided infrastructure costs.