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Andrew avatar image
Andrew asked

smart monitor bmv712

I have installed the smart monitor BMV712 WITH 2 x 100ah lithium batteries. I also have the victron mttp from my 390w solar panel as well as a 240v vivtron charger for when I am on mains power. I think I have wired the monitor correctly. My issue - I plug in the communication cable. I have 100% SOC. My MTTP is on float. The percentage SOC on the monitor slowly counts down after a few days from 100% to 0% even though I will be sitting on or around 13.5v float. I unplug the communication cable, replug it back in and the SOC returns to 100% and the countdown starts again. Any help would be very much appreciated.

BMV Battery Monitor
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2 Answers
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pwfarnell answered ·

It sounds like the -ve cables from the charging sources are connected to the batteries. The -ve charging cables should be connected to the load side of the shunt with the power users. If the -ve charging cables are connected to the batteries then the charge current bypasses the shunt and is not measured, all you will measure is discharge current so the SOC just keeps falling.

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Andrew avatar image
Andrew answered ·

Thank you for your reply. I have the negative from my solar panels connected to my battery. I will connect it to the load side and see what happens. Is it best to connect directly to the load side of the shunt or to the load busbar?


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