Originally Posted by 8 Builder
I have been researching LED light strips to use in the cockpit that are connected through the GAD 27. The plan is for two dimmer circuits. One under the glare shield and one for cockpit "courtesy" lights, probably under the arm rests. The problem is that the limit for each dimmer circuit is 500 mA. From what I can see, that is not too much light in lumens because you will exceed the 500 mA limit if you use over 2 feet of a standard brightness light strip. That is about equal to a 40 watt incandescent light bulb. I realize that the lights don't need to be bright; especially for night flights but how do users of the GAD 27 feel about the amperage limit and what type of SMD strip lights have you chosen?
There is a way to configure the system to make sure you don't exceed the current limitations and possibly damage a lighting bus output.
The cockpit lighting configuration page example on page 35-176 of the Rev. AF G3X Installation Manual explains how to configure the lighting bus output.
The potentiometer control is connected to the 12V reference signal, and provides a 0-12V input to the GAD 27. In a typical configuration, when the control is turned to full brightness and outputs 12V, the output is configured for 100%, which outputs maximum voltage to the light strip.
Since you already know that 100% (maximum voltage) would cause the light strip to draw more than 500 mA, you can set this output percentage to something less than 100% to keep the current draw to under 500 mA.
For example, if you find that a 70% output causes the measured current for the light strip to be 500 mA, you would want to set the output associated with the 12V input from the control pot to be 70%.
As you have said, you likely will need far less than the maximum output of this lighting strip for night operations, so there is no penalty to setting the maximum output to something less than 100% to protect your GAD 27 from damage.
Let us know if you have any questions.