Led driver interference on lcd screen but only when with 1 power source
Ok - figured this out (but I don't understand how the solution works). It is a grounding issue that causes the interference (static on the LCD). If I run two separate power and ground cables to the same battery source, static appears (tried everything, LC filter, twisted wires, inductors, caps. No difference). To solve the issue I needed to run the ground (and vcc) cable from the power source and attach it to the LCD controller. I then run a long ground cable from each component to the actual back of the LCD (which is metal as it is open frame). I stripped and exposed a couple inches of wire from each cable and put them on opposite corners, the further the better. Attached them by wedging them on the corners - couldn't solder as it is aluminum back panel. This was the only way to remove the static on the screen, having ground go through the panel. Issue solved - why this works I don't know.