Capacitor question

[TinselKoala]

I just purchased 10 Super caps. Each one rated at 1.5 farad and 5 volts.
For me to see a total working voltage of 12 volts placed across 6 of those caps can you tell me if all the caps should be placed in series? What would the total Farad count be then?   How long would a small 300 milliamp  12 volt motor run from that fully charged group of 6 caps?

You could make a 3-series, 3-parallel array using 9 capacitors. (3 groups of (3 series) in parallel). This will take you back up to the 1.5 F total capacitance and give a 15 volts rating, which will give you a little safety margin over your 12 volt charging voltage.
It's not possible to say for certain how long your motor would run, because the voltage will begin dropping on the cap array while running the motor and we don't know the minimum voltage that will run the motor.  Build the array and try it!

[DreamThinkBuild]

If the caps are all the same rating you can just divide by the number in series.

1.5F/6 in series = 0.25F or 250mF

1.5F/10 in series = 0.15F or 150mF

One other thing you need with larger farad capacitors is a balancing circuit. Sometimes there is a slight difference in charging between capacitors due to dielectric absorption. This can cause one cap to have a much higher voltage than the others and can actually exceed the rating of the cap.

This is not good so we need to balance the voltage across each cell. The caps I got came with a balance circuit but it is similar to the setup from LaserSaber's site.

BoostPack Balancer Circuit Tested
http://laserhacker.com/?p=292

The circuit is simple just a diode and led across each cell. There are other ways also like using op-amp balancing but the circuitry becomes more involved.

The discharge time for constant current is:

TimeInSec = (CapInFarad * (ChargeVoltage-DischargeVoltage))/IDischargeCurrent;

So for your motor example:

CapInFarad = 1.5F/6 in series = 250mF
ChargeVoltage = 12vdc
DischargeVoltage = 9vdc for example (This is the stopping point or whatever motor minimum)
IDischargeCurrent = 300ma

TimeInSec = (.250F*(12vdc-9vdc))/.300a = (.250F*3)/.300a = 2.5seconds

The other way if you want to calculate the nearest capacitor for the load and runtime with constant current you can use this formula.

CapInFarad = IDischargeCurrent * TimeInSec / (ChargeVoltage-DischargeVoltage)

So using your motor example lets say we want to target a 1minute(60sec) run time so you need to figure out what kind of cap you need.

IDischargeCurrent = 300ma
TimeInSec = 60
ChargeVoltage = 12vdc
DischargeVoltage = 9vdc

CapInFarad = .300a*60sec/(12v-9v) = 18/3 = 6F

If anyone sees a mistake let me know.