Capacitor Question

[Ronald_raygun]

A note to everyone who reads this particular post asking about capacitors: I know that they are not allowed at FIRST competitions. Please do not tell me that they are not allowed.

Anyway, I am about to compete in a fuel-cell engineering competition, and I need some help incorporating a capacitor into my design.

What I would like to do, is develop a circuit where the fuel cell charges the capacitor prior to the race. At the start of the race, the capacitor is discharged to the motor specifically so I can get a boost in speed. My understanding is that a motor whose voltage and amperage are doubled produces four times the horsepower that a motor would otherwise do. Anyway, the capacitor discharges to the motor dumping as much energy as possible, then the fuel cell provides direct power to the motor for the remainder of the race.

I need to know exactly how I can get this to work, and possibly determine where I can get a capacitor that can reasonably do the job.

My first thought was to find some sort of supercapacitor and develop a setup similar to this. (WARNING: PDF link.)

That would help in the voltage control.

The remaining problems are:

• find and get the supercapacitor (cameras? or store-bought?)
• develop a circuit to do what I described above

A 10F (farad) capacitor holds about 36 Joules of energy, which--if dumped instantaneously--can move a 1kg fuel cell car 8.48m/s. (I think) A more reasonable speed would be 5m/s. The fuel cell can then directly drive the motor the rest of the 10m race. Average speed of over 2m/s should be fast enough, as the fastest car to my knowledge last year averaged slightly over 1m/s.

So. How should I accomplish what I want to do? I'm not sure how to design a circuit which will accomplish the starting-line-energy-dump, and I don't know where else aside from www.DigiKey.com to get a 10F capacitor.

Your help is greatly appreciated.