Purpose

Provide ventilation to the driver and battery.

Requirements

Driver

Airflow

While no quantitative requirement is set in regs, I don’t think having a pinhole sized vent will pass. Since it is left to the discretion of the inspector, we should aim to size the vent and duct such that it would not “look unreasonable” if it was in an actual car. A 2in diameter opening + duct, or an equivalent cross-sectional area, sounds like a reasonable lower bound.

Filtration

While not required, since it is blowing at the driver’s face it would be nice if it did does not suck through fine particulate matter from the road. Intakes should also protect against water ingress.

Battery

Airflow

The intake/exhaust and ducting should aim to maintain a cross sectional area greater than a 4in diameter circle. This standard is currently based on nothing other than it feels off to have ducting less than half the area of the fans, which are a circle approximately 6in in diameter.

Duct Path

Below are concept sketched for the duct path for both the intake and exhaust of the battery box.

The exhaust will be fairly straightforward, routing the ducts straight back towards the tail, where both ducts will converge to the same opening in the car’s tail.

For the intake, the ducts will be routes towards the edges of the aerobody, outside of the chassis (there seems to be a lot of room to work with so this shouldn’t be an issue?). The intake ducts will vent through the front wheel wells, which can be accessed through the front ribs on both sides.

Battery Box Duct Attachments

I assumed a duct diameter of 6in for both the intake and exhaust, but that can be changed to 4 depending on what battery’s plan is.

Filtration

We should try to maintain the same standard as for the driver, although there might be some room to relax it a little when it comes to fine particulate matter.