Yes - It disconnects the starting battery from the house circuit when engine is OFF. Thats why I said the power source for the dash switch that operates the constant current relay should come from the ignition switch. Ignition switch OFF, relay deenergized, start battery disconnected therefore no drain on it while camping. If you use a switch instead of a relay then you you have to remember to turn the switch OFF. You might appreciate the relay approach after having to get a jump start a few times when switch was forgotten and both start and house batteries are drained. A digital isolator serves the same purpose because the diodes only allow alternator charge current to flow towards the battery not the other direction. Unfortunantly, there is a voltage drop across the diodes which does not allow full battery charge.