On May 13, 2008, at 8:57 AM, David VanHorn wrote:
> Those ratings should be maximums, typical at typical temperature might
> be a LOT lower.

I'm also wondering if there's a difference between leakage "during  
charge" vs "during discharge."  Supercaps blur the line between  
batteries and capacitors a bit, and a NiCd or NiMH battery (for  
instance) will exhibit high "leakage" when connected to power (so  
much so that you have to limit charging current externally), but  
don't have any where near that amount of "self-discharge" when not  
connected to anything.

So PERHAPS, if you have your 1F supercap connected to a 2.5V voltage  
source, you get your 0.5mA of leakage current flowing even when the  
cap is fully charged, and yet if you remove the voltage source, the  
"self-leakage" is a different thing.

I couldn't find an actual leakage spec for the Cooper Bussmann  
aerogel caps I'm most familiar with, but they DO specifically mention  
applications requiring "microamps for days"...

BillW

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