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imyourmaster
11-21-2013, 12:01 AM
Please help out. My '08 X2 has two batteries (dedicated house and dedicated starting) connected to a Blue Sea Dual Plus battery selector switch (Part number 6011 - off/on/combine) as well as a BEP Marine VSR dual sensing voltage relay (part number 710-125A-DS) for automatic charging purposes. According to the Blue Sea spec sheet, the two batteries should be isolated when the selector switch is in the "on" position...meaning the house and starter batteries are both "live" while each is supplying power to their respective demands (starter vs house electronics). With the engine turned off and the key in the accessory position, my stereo shuts down when I disconnect the positive wire from the house battery battery, which makes sense. What I don't understand is this - why does the stereo shut down when I disconnect the positive wire from the starter battery? If the two batteries are isolated when the switch is in the "on" position, the stereo should be receiving power from the house battery even if the starter battery is disconnected....or am I missing something?

Kweisner
11-21-2013, 06:37 AM
Could it be that one of the 12v trigger leads is commected to the starter batt circuit? IOW, house batt is providing the consumptive power for the head unt and amplifiers, but the on/off trigger is tied out to the other batt and when disconnected, there's no trigger voltage.

MLA
11-21-2013, 09:10 PM
I would guess that the head-units yellow B+/MEM is wired to the house battery and the red turn-on wire is wired to the starting battery. If either is disconnected, the head-unit turns off.

jafo9
11-22-2013, 08:10 AM
how soon after you turn off the boat are you testing the battery? i've got the blue sea system installed on my pontoon which has a 12v fridge. i installed it so i wouldn't have to worry about leaving the fridge on and not being able to get home at the end of the day. the ACR combines the batteries after the start reaches 13.6v (iirc). i installed a 2nd voltmeter on my helm so i can see this better. it takes a few minutes for the alternator to top off the start battery and then "overflow" to the house battery. the batteries stay combined until the house drops to a certain voltage. i can't remember this exact number, but it will take a little while for the voltage difference to occur and then the ACR isolates the batteries. if you are testing too soon after shutting off the motor, you may not have reached the voltage difference to isolate the batteries. there is a light on the front of my ACR which indicates when they are combined. hope this helps.

imyourmaster
12-02-2013, 05:22 PM
how soon after you turn off the boat are you testing the battery? i've got the blue sea system installed on my pontoon which has a 12v fridge. i installed it so i wouldn't have to worry about leaving the fridge on and not being able to get home at the end of the day. the ACR combines the batteries after the start reaches 13.6v (iirc). i installed a 2nd voltmeter on my helm so i can see this better. it takes a few minutes for the alternator to top off the start battery and then "overflow" to the house battery. the batteries stay combined until the house drops to a certain voltage. i can't remember this exact number, but it will take a little while for the voltage difference to occur and then the ACR isolates the batteries. if you are testing too soon after shutting off the motor, you may not have reached the voltage difference to isolate the batteries. there is a light on the front of my ACR which indicates when they are combined. hope this helps.

Hi Jafo9, Thanks for the reply. Everything you say makes sense...I'll pay close attention to red light on the ACR next time I test it and wait until they are isolated. There is a very good chance I tested too soon...

imyourmaster
12-03-2013, 06:42 PM
I posted my question to the guys at Mastercraft....this was their response:

"The reason is the systems are tied together via ground in the boat. And requires both batteries installed to function properly."