Issue with Blue Sea's Add-A-Battery Kit (new install)?

hostage

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Last fall, before I put everything away, I decided to add two batteries to my boat. I have one battery to start the boat and the other for the house (listening to radio w/o fear). I tested to validate that everything came on, before I put it away for the season and the start of this season. I dropped it off at my marina for them to check out a few other things and they said everything looked great. Though it looked like my house battery was dead, when I tried to use it, so I combined the batteries and everything came to life. After a while of crusing around shut it off took a look at a few things and switched it to "On" and it appeared that things were working. Though after running it for a while it appears that the house battery is only getting a charge, when the battery switch is set to "combined". I tested both batteries after I combined them for a while and I was seeing 12.2v on house and 12.6 on the starting battery, while the engine was turned off. The voltage of the electric system was about ~13.2v, while the engine was running, which seemed a bit low. Both batteries are about 4-5 years old, so I am planning on replacing the starting and using the old starting as the new house.

I wish I would have tested the voltage of the house battery, when the switch was in the "On" state and the engine was running as I am guessing I would have seen a 12.2v on the house, then that would have meant the relay wasn't switching on. Maybe not enough voltage is being supplied via the alternator as it looks like I am supposed to have more voltage than that?

I also got a CEL after a few minutes though no limp home mode or anything like that. I am wondering if the low voltage caused that.

Note: I used a Multimeter to check the battery voltages of the batteries. Though I used the NMEA 2000 system to view the voltage of the system via the MCU. I should have used my MM to test the system w/ the motor on.
 

alldodge

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Most likely the house Bat will need replacing. Put on charger for a several hours, then disconnect charger and let it sit for a few hours. Measure it, if its low then it needs replaced
 

hostage

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I bought a new Starter Battery and moved the old starting battery as the new house battery. All worked well yesterday. The voltage of both batteries was over 14V, when on so the relay is working. Though still got the CEL.
 

alldodge

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Voltage output is good but somewhere there is a place the ECM is getting it's reading and it's not correct. Could be corrosion
 

hostage

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Voltage output is good but somewhere there is a place the ECM is getting it's reading and it's not correct. Could be corrosion
If I reset the code by using the battery switch, it takes a few minutes for it to show it. It isn't immediate it happens at Idle or at crusing speed.
 
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