Being new to the forum please let me know if this is the correct place to setup this thread.
I’ve been researching how to build a LED moth trap and come up with using the LEDs below to replicate a mercury lamp spectrum. I’ve learned a fair bit after reading a number the threads here and I’ve come up with running 8x3watt LEDs in series made up of :

Colour No Vf (V) If (mA)
UV 4off 3.9-4.5 700. See ebay, data sheet not available
Daylight 1 3.2-4.0 750. See Futureeden for the rest, data sheet available
Warm, Blue 2 3.4-4.0 750
Royal Blue 1 3.4-4.0 750
Violet 1 3.5-4.5 750

And using a step up/down boost buck voltage converter, See Ebay. Chose this after working out the input supply voltage i.e. Vin = Vo + (Vf x LEDn) and supply wattage = Vf x total LED current, running all at 3.5v giving about 350mA. I aim to use portable Li-ion R25 battery's to run the LEDs for an hour to start.

I'm assuming that the If of a given LED will be exceeded some where between the minimum and maximum Vf, yes? And if so would I be better running a supply voltage for less than 3.2V?

Will this setup work or have I miss understood the theory?

 

To run LEDs, don't go for a constant voltage supply, but a constant current one. LEDs are current operated devices so select the current you want, and not the max rated current either, and then design the supply around that.
Another thing you need to take into account is battery management. You will kill the battery if it is over discharged.

 

To run LEDs, don't go for a constant voltage supply, but a constant current one. LEDs are current operated devices so select the current you want, and not the max rated current either, and then design the supply around that.
Another thing you need to take into account is battery management. You will kill the battery if it is over discharged.

Dendad, Thanks for the comments, and I take your point about the current. As regards the killing batteries I've not as yet given this much thought yet.