In article ,
Jim Thompson
wrote:

On 13 Aug 2014 04:31:20 GMT, EngineeringGuy
wrote:

[snip]


Jim... I haven't vanished, just out of town. I don't quite understand
what clairification you require... 10 caps in series to give 27VDC total
operating voltage.. each with "something" in parallel to prevent over
voltage... overvoltage will cause "super capacitors" to short and fail..
that "something" must be such that it will not discharge the capacitors
when the 25 volts is removed, turned off, disconnected, not charging,
etc.

Bill

How much shunt resistance across each cell is tolerable when _not_
charging?

...Jim Thompson

I've seen ratings of 2 to 10 microamps internal leakage per farad at
25C after holding the voltage for 72 hours. That's around 0 to 0.5V per
day self discharge? The working voltage depends on temperature so
getting them hot can take them 0.5V down from a full charge quickly.

I've used them to keep mobile solar devices working as they pass through
shade. They're hardly ideal capacitors since you're moving charges
around in two films of carbon gel soaked with electrolyte. Their
voltage fluctuates for a while after sudden charging or discharging.
Some models have an ESR so crazy low that 0.1V of residual charge can
weld the pins together.

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