Selfrunning cold electricity circuit from Dr.Stiffler

[poynt99]

Paul.

What type of current source are you using? Was the current steady while it was charging?

Try a similar test with your biggest electrolytic type cap and compare.

How are you calculating the capacitance?

.99

[poynt99]

The ESR of the BCAP0650 is 0.8m Ohms.

.99

[PaulLowrance]

EMdevices,

Tomorrow I can analzye the caps resistane, but lets remember these are ultracaps. The datasheet of my bcap650 shows resistance (ESR) of 0.8mOhm (8e-4 ohms). 0.8mOhm * 199.2mA = 0.159 mV. That would not explain this effect.

Paul

[EMdevices]

Capacitance = C
Total Charge = Q
Voltage = V

C = Q/V      (by definition)

so we don't know the total charge in the capacitor (unless we integrated from zero, as my hybrid vehicle does)

So we use a difference

C * V1 = Q1,         and C * V2 = Q2

then we take the difference

Q1 - Q2 = C V1 - C V2 = C (V1 - V2)

but Q1 - Q2 , which is the total charge that flowed, is equal to the current multiplied by the duration of time that it flowed or I*t     (current is coulombs/sec)

so putting it all together

C = I*t / (V1-V2)


P.S.   Paul I see your posting above mine.  Yes they seem to have a low ESR, but it varies.  Everything they spec has some reference/standard they go by, like Dr Stiffler hinted at. I don't believe for a minute that the resistance stays at that low value no matter what current is drawn.

Oh, one other suggestion,  why not start with the same voltage and drain it at two different rates?  Also why work with such low voltages, go up to 1 volt or more.

[PaulLowrance]

C = I*t / (V1-V2)

That's the equation I used.