Depot charging power limits vs fleet size?

We’re scaling our delivery van fleet from 10 to 30 EVs, but our depot only has a 500 kVA connection. Staggering overnight charging gets tricky when every van needs a full charge by 6 AM. Has anyone installed battery storage or load management systems to stretch the existing feed? Or are you forced to upgrade the transformer? Also curious if you’ve negotiated lower rates by shifting charging to certain hours. The math seems tight for 30 vans with 80 kWh packs. Any real-world numbers on max chargers per site with smart scheduling would help. We’re trying to avoid a costly grid upgrade if possible.