I want to install a battery monitor shunt into the negative line from our TT batteries. Our DIY aftermarket battery cutoff switch sits in a junction box between the two separate battery boxes (attached photo).
Now I want to add an after market battery monitor more accurate than the OEM display. The monitor I purchased (did not come with an instruction book) includes a 350Ah shunt to be installed on the negative cable as well. Since both the cutoff switch and the shunt are to be installed on the negative line, does the shunt get placed between the battery terminal and the cutoff switch, or does the cutoff switch go in between the battery and the shunt?
If the shunt comes first I would be able to check the battery levels during warmer weather between outings without removing the batteries, but I would think this configuration allows a parasitic draw from the monitor screen.
If the switch comes first in line there is no parasitic draw when the switch is off, but I also can't see if the battery power is good without turning the cutoff switch back on.
I can live with either wiring order, but which order is best practice? Shunt before switch? Or switch before shunt?
Either method, I will likely install a third battery box between the existing two batteries, and rewire both the switch and the shunt within the third box in the order O settle on. Thanks for your input in advance.