Hi everyone, hope someone can help? I just started playing around with some LED lights, trying to make a really bright Flounder light that can last at least 6-8 hours on the supplied battery. I was told if I used a "step-down", I wouldn't need resistors, (since the step-down does this in an essence), which I haven't, But the step-down keeps burning up? Here's the set-up I've been playing with... - 18vdc (power drill) battery. (unknown amps). - Step-down driver.... input 8vdc - 36vdc, output 1.5vdc - 36vdc - 3w LED Cree : ~ Reverse Voltage: 5.0 V ~ DC Forward Voltage: Typical: 3.8V Max: 4.2 VD ~ DC Forward Current: 700mA ~ Luminous Intensity: 170-190lm I use a volt meter to tune the Driver to a constant 4vdc to drive the LED. And the driver burns up and then the bulb after about 5 minutes. I was told I needed to add Ceramic Resistors, between the driver and battery, and between the driver and LED. (But what size?) I was also told I don't need extra resistors because of the driver? Which is Right? Or should I just add resistors between the battery and LED and do away with the Driver completely? Also, what is meant by "Reverse Voltage"? I have a 6vdc battery with a 4.5 amp capacity. But I want to use the 18vdc battery longer use, time wise. This is why I have the Driver, when 1 battery deletes, hook up the other one. I'd like to put 3 - 3w (180L) LED bulbs together, and run them off the 6vdc and/or the 18vdc battery so the LED's will last for at least 6-8 hours on 1 charge. I want to use either the 6vdc and/or the 18vdc battery because they are lightweight. I could go with 1w LED's so long as I can get the brightness needed to light up a distance of about 12' underwater to see a Flounder, and get 6-8 hours usage. Any help would be appreciated.