Powering Arduino Uno, CAN Crocodile and NeoPixels from Car
A reasonable estimate for current consumption of 5V NeoPixels is 60mA per pixel. For 186 pixels, that means about 11.16A at 5V; well over the 2.4A of the adapter being used for your other components.

There exist modules called "DC-to-DC Buck Converters", which can step down the 12-14V of your automobile to pretty much any voltage under the input voltage. To be safe, look for a buck converter of at least a 75W rating, and which meets your criteria for input and output range (minimum of 12V input, could be rated higher; output range inclusive of 5V.)

Be sure that the Ground connections for the NeoPixel power supply and the other supply are shared/connected, but don't share the +5V line between supplies.