View Full Version : Perko switch and Voltage sensitive relay

02-11-2009, 10:11 PM
Diesel's thread on the isolator install was awesome. I didn't want to clog up his thread any further when I have 2 questions about my 06 X-45. The boat has both a perko switch and a module labeled 'Voltage Sensitive Relay' (VSR) going to 2 batteries. My understanding of how this works is that the Voltage sensitive relay charges one of the batteries until is senses that it is fully charged, and then it will put power to the other battery.

Question 1: How does the Perko switch fit in? I think that the switch tells the VSR which battery is the starting battery, so it knows which battery to charge first. So that can be set to 1, 2, both or none. Am I right to think this is somewhat retarded? My amps are wired straight to battery #2. It would seem to me that the perko switch would only serve to confuse the VSR and leave me with a dead starting battery. Or I should only use the Perko switch in the 1 or 0ff position so that I never confuse the boat about what battery to charge up first?

Question 2: I have upgraded the power of the stereo system substantially and really think that 3 batteries are going to be better, so I am thinking of adding a 3rd battery to the setup so that I can have a bank of 2 batteries dedicated to the stereo and then 1 battery that is only used for starting. The third battery will have to go to a place that is only 8 inches deep, which means I am looking at sealed batteries that will have to lay on its side. If the 2 stereo batts are separated from the sealed battery (probably an Optima) then will I be OK as far as keeping them all charged? Or would I be risking problems due to different charge rates and discharge rates if I did not go with 3 optimas?