Buses will have fairly large batteries (Bird does 150kWh). The percentage of the battery needed for heat goes down as size goes up because the interior size is relatively negligible in how much added heating capacity is needed to keep the bus warm.
But yes, probably wouldn’t be too crazy to throw on a propane heater in especially cold climates.
Right, and the EVs that lose that much range are the ones with the smallest battery packs. The heating requirement as a percentage of the battery pack goes down as the battery gets larger. It takes roughly the same amount of energy to keep a 40kWh battery warm as it does to keep a 150kWh battery warm.
The same logic doesn’t directly translate for a car as a bus.