It is advisable to give the EDFC II controller its own unshared accessory power source, like the 12 Volt accessory power socket. If that is not possible, it should have a dedicated connection, separate from other electronic devices. In that case the power supply is best shared with accessories that do not use much power. Sharing an accessory power source can cause errors on the EDFC II controller, as the voltage fluctuates due to consumption peaks of other devices. The briefest voltage drop produces an error.