There is no universal “best” DC charger size. A 20kW unit can be sensible in one project and painfully slow in another. The gap between those outcomes is usually application fit.
Start with the use case
The headline power number only matters in context. The 80–160kW range suits public charging and faster fleet use more naturally. Use fast DC charging in a sentence that gives readers a concrete reference for power range, mounting options, and operational features such as OCPP, OTA, or power management. It lines up better with shorter dwell-time expectations. Connector strategy matters because queueing can return if charger count is too low. A 20kW or 30kW unit can be perfectly rational if vehicles have longer dwell times or if the site is constrained. By contrast, a public quick-stop location may need 80kW, 120kW, or more just to keep queues under control.
Then check the power reality
Buyers also need to check what the vehicles can actually accept. Installing very high-power equipment for a fleet that rarely uses that power does not future-proof the project; it mainly shifts budget away from civil work, software, spare capacity, or additional bays. The better question is how much energy each vehicle needs during the actual charging window.
Power selection is also tied to upgrade path. Some portfolios benefit from starting at a lower band and scaling when usage stabilizes. Others should design for expansion from the start because a utility upgrade will be difficult later. Either way, the site model should lead the charger model.
There is also a psychological trap here. Bigger numbers feel safer because they look future-ready. But future-ready can also mean flexible software, expandable power, and a layout that allows more connectors later. A charger that matches the first two years of demand and can scale cleanly is often the smarter move.
One caution worth noting
A charger should earn its keep in daily operation, not just in a proposal deck. That is the standard worth using.