Failure mode of supercap at overcharge?

Dunno if you are in the US, but Digikey seems to have one that should work for you.

For $12.24 you get 33mF 150mOHM 4.5 volts.

If that's too much money maybe you could specify your needs a little more c learly. If the problem is mainly high frequency you don't need as much capa city. Of course that depends on the current. Even in supercaps a lower capa city will save money, I don't feel like the math right now but a thirtieth of a Farad is ALOT. I mean bypassing one Hertz or something at probably mor e current than the battery can produce would be no sweat unless you are usi ng a huge battery, but then you wouldn't need this, right ?

Then there is the voltage rating. If you need 4.5, it would be a better ide a to exceed the ratings (grrrr) of say a 4.0 volt than a 2.5 volt for examp le.

It all works against the money. The $12.24 cap would definitely do it, but so might many cheaper ones.

Probably electrolysis of the electrolyte. Some organic ionic liquid or something. Kind of like overcharging lithium ion cells.

Tim

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