Posts: 2
Registered: ‎04-17-2011

Re: Monitors & other in cab electronics Power Source Question

Tyler makes some good points, but there are other reasons why it is best to connect directly to the battery. In digital systems noise can be a problem and any time you connect downline from the battery terminals there is an increased chance of electrical noise on the line. The technical reasons can get complicated but all conductors have some resistance, and if current is flowing from the battery through those conductors, voltage is dropped across them. The longer the distance from the battery, and the higher the current, the more voltage. The amount of voltage changes as the devices drawing the current turn on and off. This becomes noise. In some cases this noise voltage can be enough to cause errors, resets, and other effects in the monitor.