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voltage regulators and supercaps? Answered

i have 12 .22F 5 volt supercapacitors that i bought recently. Ive been thinking about making something like the Mintyboost from Adafruit but am unsure on how to do it with supercaps.
Any help is appreciated as this is stumping me pretty well.

thanks, bud

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user
icengBest Answer (author)2013-02-19
 Ahem     12  Capacitors (o.22F @ 5VDC )

IN SERIES
  • V = 12 × 5V = 60 V DC
  • C = o.22F  / 12 = o.0183F 
  • E = C × V2 / 2 = .0183 × 60  × 60 / 2 = 33 Joules


IN PARALLEL
  • V = 5 V DC
  • C = o.22F ×12 = 2.64F
  • E = C × V2 / 2 = 2.64 × 5  × 5 / 2 = 33 Joules

Which do you need for your application :-)

A

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user
budhaztm (author)iceng2013-02-20

For my application I would need 5volts. About how much maH would you suppose I could get from th eparallel setup? Using resistors to slow the discharge?

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user
iceng (author)budhaztm2013-02-20
Try 500 ohms which at  5 VDC will pull I = V / R = 5 / 500 = 10 ma
  • Charge the capacitor in position [A] for under 1.9 Hrs
  • Or put a diode across R to charge in 3 min
  • Time Constant = RC = 500 × 2.64 = 1320 sec = 22 min
  • Switch to position [B]
  • In 22 min a start current of 10 ma will exponentially decay to 3.7 ma
  • It is a rule of thumb that a capacitor discharging through a resistor will decay to 37% in the RC time constant.

A

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frollard (author)2013-02-18

Mintyboost just takes a lower voltage and boosts it to a stable 5v...

find a way to charge your supercaps, then install them in a mintyboost. They won't be very high capacity compared to batteries, but they can charge and discharge more quickly.

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