After reading this
https://community.victronenergy.com/questions/122850/lynx-shunt-wrong-voltage-value.html
I decided to create this new thread to give a better overview about the above problem to Victron.
First things first, IMHO, it is NOT a show stopper for us users. It is just something to consider and adjust in (the shunt/system) settings if necessary. According to my investigation is only an offset. Nothing critical just and irritation
- Problem Description:
Lynx Shunt reports to the VE.CAN (what you will see then in VRM or Remote Console) a LOWER voltage reading than the one provided by other Victron devices (like MPPTs and Inverters). This is also confirmed by external measurement with multimeters.
- Details
1) Only 48V System seems to be affected by this problem
2) The max offset reported between shunt voltage measured and "the rest" is about 500mV
3) No solution is officially provided by Victron
4) No DC voltage recalibration is possible on the Lynx Shunt
5) Some users ended up swapping the Lynx Shunt with the SmartShunt, since it costs less and perform better.
6) For ESS System the MPPT/Inverter DC Voltage is shared, see here (thanks to the immense @Some-user)
this is also why the DC voltage there is the same across those devices.
- How do I know if my Lynx Shunt is affected by the above problem?
The simplest and most effective way is to create a custom widget in the VRM plotting the Lynx Shunt voltage and the "DC system voltage". If you will see two lines with the same shape and the shunt voltage is lower, then welcome to the club.
Example of the above widget:
The more complicated way is to download the .xls file with the raw data from VRM and do some statistic on them.
Here below you can see some of my DC voltage values:
Average: the average of the DC voltage reported without the Lynx Shunt one
delta AKA Lynx Shunt error: the above value minus the Lynx shunt DC voltage.
Here below the statistics of the Lynx Shunt error DC voltage error:
With such a small variance, I am sure the error is just a constant offset.
In other words my Lynx Shunt ALWAYS reads about 152mV lower than the rest.
- Immediate countermeasures
Lower the affected DC Voltage setting by the know offset error.
Example with 200mV offset:
I want 100% SoC at 55.5V, enter the value 55.5-.2=55.3V
- What we user can do to help Victron:
Report the problem with the Lynx Shunt serial number.
Here the list:
152mV, SN 
- What Victron can do to solve this problem:
The most effective and elegant way it to provide a FW update with the new feature to calibrate the Lynx Shunt DC voltage. Mostly copy paste of what is already implemented for the DC current measurement.
Many thanks to all users who reported the problem first, expecially @Michael Schmidt
