interesting one
it's so long ago since I worked with Capacitors, much has changed, we used to call them cans.
are you thinking of using one instead of a battery?, if so then you need to consider if the VCU would be happy trying to control dynamo charge into a Capacitor, I suspect discharge from a Capacitor would be less controllable than from a battery, but as I said much has changed and maybe modern capacitors are more like batteries than previous,Looking forward to some more up to date info then I can provide