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Hi,
in my boat I've got a BMV 712. It shows my batteries are at 100%soc, but the voltage is dipping to 12,2 this winter. How come it's still 100% SOC with this voltage?
And another question, since the beginning, the BMV is not giving any temperature. Tried flipping the power and the temperature cable (don't see any difference). Is there a way how to get this working
@Mvmoock, it's important to note that the BMV does not calculate SOC as a function of voltage, but rather as a function of total bank capacity (Ah) as programmed plus current in or minus current out. If you start out with full Pb batteries and your BMV at 100% SOC and you let the batteries sit -without applying loads or charges- given enough time, the voltage of your batteries will drop (because Pb batteries self-discharge) but the SOC percentage shown on the BMV will not, because it cannot see the self-discharge of your batteries. This is perhaps what's causing the issue.
If you are running loads and/or chargers, but not seeing the SOC change, then you have the shunt connected incorrectly and/or some of your loads are bypassing the shunt, which of course cannot be the case should you wish accurate readings. The only thing connected to your battery negative must be the "battery" side of the shunt, while all other system negatives, including all load negatives, charger negatives, chassis grounds, and etc., must be connected to the "loads and chargers" side of the shunt.
You should also double-check that you have correctly programmed the total Ah capacity of your battery bank into the BMV.
The temperature sensor must be the sensor specific to the BMV-702/712, and must be connected to the POS battery terminal, with the fused red lead being connected to the "B1" port of the shunt PCB, and the black lead being connected to the "B2" port. This must not be reversed, and please note that use of the temperature sensor means you must not use the single-wire red fused POS battery lead that is included with the BMV.
After proper connection of the temperature sensor, you must then configure the BMV to recognize that the aux port on the shunt PCB is being used for temperature. In VictronConnect, this setting is in Settings>Misc>Aux Input. See attached screenshot of the setting.
Should you have continued problems, please review the BMV manual to ensure that it has been installed correctly and, if the unit has been correctly installed and programmed but is still not functioning properly, contact your distributor for additional troubleshooting of the device.
Thank you for the very extended answer.
The SOC answer is clear to me. But I found it a bit strange it can messure the voltage going down and not affecting the SOC. Probably a good reason.
I thing I've received 2 power cables with my BMV (two separate red cables with a fuse). Changing the settings in the app doesn't change anything. And swapping the cables on the shunt neither. So I think I will order a thermometer cable then.
Thanks for the answers.
