I'm making an array of 11 3.3V LEDs, and I've got multiple various setups possible depending on source voltage (batteries supplying either 6V, 9V, or 12V) and whether I decide to put a bunch of the LEDs in a combination of series/parallel or all in parallel. I need to maximize battery life, so obviously current drawn from the source is a concern, but I've got a dilemma. Is it better to run with a lower voltage supply and a higher current drawn, but large battery capacity/mAh? Or better to stick to a lower current with fewer parallel bits, but higher voltage and lower capacity/mAh? My setup right now is with a 6V source with every light in a parallel circuit (and appropriate resistors), which draws 220mA if I did my calculations right, and (assuming I use four alkaline AA batteries, which have 2700mAh according to Wikipedia) will last the longest compared to the 9V or 12V. That's the highest current drawn out of all my possible setups, though...? That does not look very efficient. I'm new to the world of hobby electronics, though, so it might be a bit of newbie paranoia, but I thought I'd throw it out there anyway before I start putting anything together permanently.