This is a DIY install for a 3watt LED Indicator array commonly found on ebay. After a crash due to low battery, wanted to install a few indicator LED's to see it up high. The APM couldn't power bright enough LEDs to be seen in daylight, so looked to this module. It's pretty compact and definitely visible. Works from 5-30volts so it'll work on pretty much any battery. Using a 2S(11.1v) currently and it's plenty bright. I'd recommend looking at two, one for the front and one for the back, so you can see it in any orientation.
My eventual APM Pinout
Black - any pin along the grounding rail (closest to edge)
Red - Camera (depends on your camera/trigger)
Green - A4 Aux LED (programmable from APM)
White - A5 (beeper/status) or A7 (ARMED/DISARMED)
Blue - A6 (GPS lock)
You can search on ebay for "LED Indicator Module V1.0" from flying-xys. Fast delivery and only $10 bucks shipped.