(For Admin) A few suggestions.

[Mr. Ninja]

Looking at your robot tutorials, and what I have been researching, I have a few suggestions.

1) A place for super capacitors in your battery tutorials, they actually look like (to me) a viable energy source.

2) A calculator for finding out how long a X amount of Farads will last on X current draw at X voltage.

Thats all, they were just a few suggestions. (You're doing a great job on the site)

[Soeren]

Ji,

2) A calculator for finding out how long a X amount of Farads will last on X current draw at X voltage.

Any calculator will do. The formula is:
C*U/I
Where:
C = Capacity in Farads
U = Allowable Voltage drop
I = Current
So, if your start voltage is 5V and you can use it down to 4.5V at a 5mA draw, a capacitor of 1000µF will give you: 0.001F*0.5V/0.005A = 0.1 second

Super caps are good for very modest currents, like very low power controllers only.