One for design techs.

on 04/01/2021, Dave Plowman (News) supposed :

I have seen large capacitors used as the power source for solenoids on one car. Slow charging via a resistor, then fast discharge via the solenoid when triggered.

Indeed - what I am curious about is the use of massive relays rated at hundreds of amps to switch under 20. Obviously their coils have a much lower resistance than a 30 amp one which would typically be about 150 ohms. So need much larger caps too.

Maybe Lucas had surplus in stock and decided to "second-purpose" them.

I'm more interested in the large capacitors. I can't think of a more hostile environment for a capacitor than a car engine compartment, particularly if it is an electrolytic to get that long pulse. Or was the control unit in a cooler place?

It's situated inside the rear wing, so temperature depends on the weather.

I doubt you'd use surplus stock on a design hoped to sell many thousands?

This is what happens whe a designer has no idea on how to do something and so decides to try the first thing that comes into their head with no thought to failure modes as the device ages, sticky solenoids, broken springs and any detection of whether the job was done as that will cost them the cost of another bit of wire.

Brian