Correct, the source of electrons (dynamo, alternator,
flux-capacitor) doesn't matter - it's the regulator which typically causes any leaking.
If you have a multimeter you can measure it.
- Set the meter to measure current,
- Switch off anything on the bike which might draw current - might seem obvious but...
- Remove the wire(s) from one side of the battery so that the battery pole has no other connections,
- Connect one side of the meter to the wire(s) you just removed from the battery and the pole on the battery which now has no wires on it,
- You are now measuring the total leakage of your electrical system,
- If the current is more than a couple of milli-amps something is leaky, if not then everything is good and you don't need any magical extra switchery.
If it's more than a few milli-amps it may be the regulator. On the other hand, you might have other stuff on the bike which leaks depending upon what state your bike is.
I have an Alton and Podtronics regulator and the battery never leaked away. OTOH, I don't use automotive batteries on the bike as I don't have electric start so don't need a massive battery.
All batteries self-discharge to some extent typically getting much worse as they get old.
Hope this is clear, let me know if it's not and I'll try again.
Cheers - Steve