On my boat I have a single 4D as my house battery and a Group 24 as my starting battery. Both are in plastic battery boxes on either side of my engine so the distance between them is about 6-10 feet. These batteries are wired separately. I was going to connect the shunt to the house battery as battery 1. I understand the wiring for that, simply removing the negative cable currently on the battery and placing that on the load side of the shunt and running a short jumper from the battery side of the shunt to the battery, then the small red wire to the positive of that battery.
For connecting the Starting battery, do I simply run the other small red wire to the positive of the starting battery? If needed, can I make a butt connection and extend that wire to reach the other battery? I see in the diagram the negative cable from that battery looks like it should go to the load side of the shunt, but since these batteries are wired separate do I even need to worry about that?
I also have the temp sensor but I think if I am monitoring two battery banks I cannot use that, correct?
Also, where should the shunt be installed? Inside the top cover of the battery box or elsewhere. It is on a boat so not sure about keeping it protected from the bilge area.