supercap leakage

To be fair it is 130ua at it's maximum rated voltage.

I kept increasing the voltage until I got a lot of leakage.

I think it's a very good capacitor.

And declines with a time constant of days.

Look at it again, these are 2.7 volt caps and he's applying over three volts to them, where the leakage starts to increase exponentially.

Treat them with respect, don't overcharge, equalize the charge, and be mindful of the ambient temperature and they are just like any low leakage, low ESR, capacitor...

I have one, now doing duty as UPS for my modem, that I used to cold-start my truck 3 months after I charged it.

I do consider a solar cell 1-1/4" square a very low power source. The latest crop of super cheap solar walkway lights are like that. None of them can make it from dusk to dawn with the supplied nicad battery yet they all work with a 50 farad 2.7 V cap even when overcast in winter.

I'm a believer. Did you test any to destruction?

That's exactly what I wanted to explore. The data sheets don't have a v-i curve. That matters if you want to stack them in series.

Rick is not good with numbers. Or thinking before he types.

The leakage at 2.5 volts is over 100 uA. That's still more than the load I would be providing power to. It's also over three times the spec sheet value with a 72 hour soak. Real world performance can require use well before 72 hours of "soak".

Which is the reason we breadboard, build engineering prototypes, and such. Design based on the datasheets, but only accept what you can produce empirically. AND when it comes to the book and the real world, trust what reality shows.

Which... makes me an atheist.

Rick doesn't understand dielectric absorption. If you charge one of these caps, leakage initially appears high, but the leakage current will drop over time, such that the cap only self-discharges a bit.