Re: charging time
Exactly, voltage on charged capacitor is given by formula (assuming that, before charging capacitor was fully discharged):
Uc=Ucc*(1-exp(-t/RC))
Uc - capacitor voltage
Ucc - source voltage
C - capacitance in Farads
R - resistance in ohms
Resistance ever exist - it is sum of internal source resistance, wires resistance, connectors resistance, capacitor leads resistance, internal capacitor resistance, additional series resistance.
Values of above mentioned resistancem may be different from part of miliohms (wires, capacitor leads) to megaohms (additional resistors).
T=R*C - time constant
t=K*T
K=0 -> Uc=0
K=1 -> Uc=0.632*Ucc
K=2 -> Uc=0.864*Ucc
K=3 _> Uc=0.95*Ucc
....
t=2.3*T -> Uc=0.9*Ucc
t=4.6*T -> Uc=0.99*Ucc
t=6.9*T -> Uc=0.999*Ucc
For example: R=1Ω, C=100µF
t for Uc=0.999*Ucc is equal 6.9*1Ω*100µF=0.69 ms