I have boost converter powered by 2 AA batteries (3v) which increases the voltage to around 40v. I have a 12v zener diode to cap the output to 12v. Regardless of the zener diode when I connect a strip of LED lights (rated for 12v, 33 LEDs @ 20ma each) the voltage drops to 8.1v. The LEDs do light up but not to their fullest potential.
Note that the diagram shows four LEDs, but in real life there are 33 in the form of an LED strip -- they're grouped in sets of 3 (you can cut every 3). So I've got 11 sets of 3 LEDs each, in parallel, for a total of 11 × 20 mA per set = 220 mA @ 12 V.
I have a few questions:
How can I increase the current so the voltage doesn't drop when the lights are connected (I think this is what is happening)?
Am I losing efficiency (battery draining faster) by going to 40v then capping it with zener diode at 12v?
My NPN is really hot to the touch, is this normal? I'm using BC337 which has a max rating of 800ma (and BC327 for my PNP).