question

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jangeja asked

BMV 712 just started showing sporadic DC measurements.

I just noticed my DC Power numbers were jumping around -100 and 150 watts while I know the DC power was fairly constant (E.G. fan running, lights, etc.).


My system has been running fine for a couple months with nothing like this happening. I even turned off all DC Power, by opening the DC breaker and was still seeing sporadic wattage for DC power.


I'm using a victron color GX to monitor the dc power. I've attached two screenshots, one showing normal DC usage where you can see my fridge compressor kick off and on. The other screenshot shows the negative wattage, which I have no external non-victron chargers. I have a victron mppt charger and a multiplus. The multiplus was disconnected during my tests. Whats even more interesting is the screenshot was taken when the DC breaker was disconnected. Could this be a bad rj45 cable ? That would be very unfortunate since my rj45 cable run is behind a lot of my furniture and would be pretty cumbersome to run another one. The sporadic and incorrect current is causing my battery SOC to be thrown off. Im not really sure how to diagnose this any further without having a replacement cable or unit. Has anyone else had this problem ?


Sporadic DC wattage


BMV Battery Monitorgx device
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1 Answer
jangeja avatar image
jangeja answered ·

Did some more testing and here is what I found:


I disconnected all power to the battery, leaving only the bmv connected. Previously my tests I had the mppt solar charger still connected. I saw from the bmv the wattage had stabilized to 2 watts. So I zero-current calibrated the bmv and connected everything back. I saw some oscillating for the dc power on the Color gx, but soon after it stabilized to what I would expect.

Such a weird occurrence. Could the solar charger have been causing the weird DC system power usage ?

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