In the typical location behind the driver, we are concerned with side and rear impacts.
Per F.11.2.3, on the sides and rear of an accumulator in the typical location behind the driver, create 25mm clearance to any non-crushable object.
As of 2024, a buffer is not required above the bottom plane of the chassis.
As of 2024, a buffer is not required above the top of the accumulator.
A sidepod accumulator location (strongly discouraged) would be at risk not only from side and rear impacts, but also front and top impacts.
How to tell if an object is crushable or non-crushable?
Imagine crushing the object against the accumulator.
If the accumulator is not damaged (lightweight, thin bodywork or ducting, soft cooling tubes, individual small-gauge wiring, etc.) then the object is crushable.
If the accumulator is damaged (motors, motor controllers, large HV wiring, electric fans and pumps, etc.), then the object is non-crushable.
For any non-crushable object mounted on the accumulator, extend the 25mm clearance around the non-crushable object.
A 25mm air gap between the driver and anything mounted on the accumulator is also required by T.1.6.3.b.