Multiple Parallel Led Flashlights

I bought a bunch of led flashlights from the dollar store and would like to wire them so they all run off the same source. The flashlights contain 3 white leds wired in parallel, no resistors, and runs off of 3AAA. I would like to hook 6 of these flashlights to one dc power supply. I have multiple power supplys ranging from 5v 1.5A, 9v 400ma, or 12v 1A. I would just like to wire off the battery holder and drop a resistor from each flashlight. Is this possible? I started to open up each flashlight and rewire the leds in series, but it is too much work...

Any help is greatly appreciated!

- Adam

I would connect three flashlights in series, then two strings in parallel. That should give you about 9V. The 9V supply might be just right for that, but I'd start with a 1 ohm resistor in series just in case. If this overloads the supply, then use the 12V one with an appropriate resistor (we have no way of calculating it until we know how much current the lights draw).

DIWdiver said:

I would connect three flashlights in series, then two strings in parallel. That should give you about 9V. The 9V supply might be just right for that, but I'd start with a 1 ohm resistor in series just in case. If this overloads the supply, then use the 12V one with an appropriate resistor (we have no way of calculating it until we know how much current the lights draw).

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If I was to hook each flashlight directly to the supply, with an appropriate resistor, could I hook up more flashlights? Please bare with me, as my knowledge of electonics is lacking. What I dont understand is if I use the 5v 1.5amp supply and hook the flashlights individually via a resistor to the supply, will I run out of volts once the number of leds exceeds the supply voltage or will 5v be supplied to each flashlight?

using resistors will make the setup less efficient. Better to run in series with a small resistor than to have a large resistor on each.