Thanks Danadak, i must admit ive perused those docs over the years, but they dont tell what is the maximum voltage rating allowable for eg a cap on a 5V rail etc.
I guess these manufacturers dont have to spec it, so why bother.......just when misers like me have to buy ten 50V caps and so want to use some on a 5v rail in a prototype....instead of me having to buy say a 6v3 el cap on top of the ten 50v ones i already had to buy.
I once worked at a LED place, and the extremely experienced electronics manager there used to say that a elec'ic capacitor had to have at least 10% (and prefereably more) of its rated voltage on it to properly be a capacitor of anywhere near of the stated capacitance.
Along with that, its common knowledge that you cant use lytics with 555 timer circuits to get long delays.,....this is seconded by Babani as above.
....____
Incidentally, i used to work in a cap discharger place...for xenon flash lamps....we used to charge 615uF from say 60v to 340V in one second then flash........the caps werent much over 400V rated if at all........i certainly dont remember them being well voltage de-rated........i cant remember now, but you end up getting either 10% more, or 10% less (i cant remember which, but i think its more charge in there than you'd think......almost like you got something [an extra 10%] for nothing.) charge in the capacitor than the calculation tells you for such discharge duty.....we monitored the current going in and did the integral with time to get charge gone in...........the boss thought i did the calcs wrong.....so we both did them and we got the same....then we found an explanation of the phenomina on the web......i posted about it on a forum at the time...about end 2016, early 2017, but cant find the posts now.