good evening everyone, I need to have my cerbo gx read the voltage of a second battery. based on the value of this voltage, via nodered, I perform certain actions. can you tell me a voltage sensor that works at 12v compatible with the cerbo?
Smartshunt
I had it, but I still had 2 quite different socs: soc from the smartshunt and soc from the bms. So I decided to eliminate the smartshunt and read the soc directly from the bms. Alternatives to have 2 separate voltage readings?
I’ve seen many cases of bms where the SoC was about as reliable as the weather forecast, so I’d go for the smartshunt every time.
And you have an input for a second voltage.
so you would rely on the smart shunt and not the bms? I read many cases of misalignment where the smart shunt reads percentages over 50% but the voltage at the poles is less than 50%… we are in a sea of doubt!
That is because they did not set the SmartShunt up right, especially charged voltage.
2 Likes
… and tail current 
Depends on the battery, the BMS does more than just calculate SOC, it also sets charge/discharge limits and controls the chargers.
If we are talking about well known, supported/certified batteries, for the most part they are more accurate than any shunt you can adjust.
When you head into DIY/drop-in country, that is a different story.
The lithium install base is enormous and works just fine under purely BMS control.
Those that don’t tend to be obvious.
as for the main battery, it is a self-built battery with catl cells and bms jk. but in this discussion I was interested in knowing if it was possible to mount an additional voltage sensor directly on the deer to have the reading of 2 voltages inside the venus system. according to your knowledge, the only way is to mount a smart shunt?
For a second reading, a shunt works, it won’t be configured as the system BMV though.