I see. Maybe there is a way to achieve an even voltage between the caps? hmm, I will look into this.
yes you are right, but 10w resistors are not cheap, I will use 5watt. Now that I know I can use max 5 Amps I ordered 10x 5 ohm (5 watt) resistors. I will use 4 of them in parallel to get 1.25 ohm (this will cost me just 70 cents). 5 volt / 1.25 ohm = 4 Amps charging! 5 v * 4 a = 20 watt (just enough for 4x 5 watt resistor)