I am using a BMV 712 to monitor the battery on a travel trailer. I am an occasional weekend camper so I disconnect my battery if I am not going to be using it for a period of time. If I disconnect my battery when it is at 80% and later reconnect the battery, will it know that the battery is not fully charged or will it assume this is a fully charged battery and read 100%
You have the option of setting up the BMV to assume 100% SOC upon power up/reset or to have an 'unknown' SOC up until the first synchronisation event.
You can change this using the BMV itself - option #70;
Or using VictronConnect - under 'Settings' > 'Battery';
Mark, I discovered this option after investigating the app further. This option was not listed in the documentation I was looking at.
Will the display/app not show SOC until it syncs or once it starts charging will it show 100%
If you turn off the 'battery starts synchronized' option then I believe that it will display 'UNKNOWN' until the battery is fully recharged and the first synchronization event is achieved (voltage, tail current & time criteria met). But if you ever want to you can also 'force' synchronization.
Hi @donaldN01,
Why disconnect the BMV? The BMV is designed to use very little power less then 1mA
My advice would be to keep the BMV connected and disconnect the rest. Then it will keep the SOC
best regards
Martijn Coster
Victron Energy
Thanks for the suggestion Martijn, but I am disconnecting at the negative battery terminal and if it is going to be an extended period I will remove the battery and take it home to put it on a trickle charger. I may look at putting a battery cut off switch after the shunt so I could do as you suggest.
I agree that this is also a good option.
@donaldN01 just please be aware that the BMV will not account for battery internal discharge during extended storage or any small / negligible monitoring load under the 'current threshold' (that is set to 100mA by default).
So even if all other loads are disconnected & the BMV is kept powered/active, after a month or so the reported SOC% is probably going to be wrong anyway until the battery is recharged & the BMV synchronises again.
