Russell, I confess to confusion about your inquiry. Is there a SHUNT associated with your monitor??? Or does your photo show the item complete? Please post a web link to a manual or other technical resource where we can learn about this monitor.

In the meantime, you might want to compare your monitor's capabilities to the more popular Xantrex LinkPro Battery Monitor that I have installed on my Catalina 36 Mk II. 

You don't really have a monitor suitable for monitoring a house bank. These devices are made in China by numerous companies. They all look the same but have widely variable performance. I know a US company that imports them but it took them a year of working with the original manufacturer (not the copy cats) to get the product to actually meet design spec. They sell it as a solar system monitor and ship it with 75A capability, using an external shunt. Yours appears to be an internal shunt model which is maxed at 30A. It would be fine for monitoring a small solar array but not for a house bank as, starter or windlass loads would toast the shunt. A proper battery monitor, suitable for house bank monitoring, would generally have a 200A + external shunt, as bare minimum, with most of the quality units shipping with 500A shunts as standard. The Victron BMV-700 is generally the best value in a quality Ah counting battery monitor..

Hi...i think with a cable from the battery to the shunt is generally pretty easy. Either a local shop or Amazon can supply one. It should be a pretty short run, 4AWG will work. If you want to go bigger 2AWG is more than adequate. Also consider that this is a great time to think about a battery disconnect switch.

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Hi I am in USA but I have two boats a 36 - year 1996 and a 380 year 2000. One in NY and othe other in Florida. Anyway I installed a Balmar battery indicator on my 36 and it works great for both batteries and a separate battery indicator for my starter battery. i also use a 614 regulator and battery separator for my stater batter also Balmar products. I have serpentine belts on both boats and 160 amp alternator. On my 36 i have a yanmar 39 engine that I installed when I gave up on my universal. 

I agree with Rod. That unit is not suitable for the loads on a C36. It has a maximum current rating of 30A, which is below even the small 35A alternators the first M25’s came with. Even getting 30A thru that thing would be a big stretch will the small size of wire connections and the line loss. If you want to count coulombs (electrons) the Victron is a good unit, if you want to know how much electricity is left in the batteries the Balmar is a much better unit. Balmar is introducing their next gen monitor which looks even better than the origional - that’s what I would recommend. Lrs