Originally Posted by
flammenwurfer
So are you saying that having them in parallel will be dimmer than if I did 12 pairs of series leds in parallel? Sorry, I don't know a whole lot about electric circuits. I have another pcb and tons more leds, so I can make another light if it would work significantly better.
Right indeed. I don't know what type of leds exactly you are using, but I guess they must be rated around 3V and using close to 40mA a piece. You have put 25 in parallel which means that each of them gets around 6V and that they ask for 25x40mA. Not a good fit for your 500mA dynamo.
If you do the 12 "pairs-of-leds-in-series" in parallel, then each pair of leds will get 2x3V (Voltage drop of 3V per led) and they will ask for 12x40mA which is 480mA. Considering that the bridge rectifier diodes will burn some of the power from the dynamo, the leds should be fine handling the rest. Leds are more sensitive to too much current, but can handle over-voltage better. Standard bulbs do the opposite.
Of course you must check the exact voltages and mAmps for the leds you are using and adjust the maths to determine how many pairs of series leds you should put in parallel.
Looking forward to your test results...