Are these graphs enough information to tell me why my SmartShunt SOC continues to drop and never reach 100% charge? Is this a calibration issue at the BMS, or some kind of degradation of the LIPO battery? I'm hoping the former... The gap in reporting was due to no wifi. The system performance can be interpolated.
It would help to have a diagram of your set-up. Without it I guess that you compare the SoC reported by the BMS with the SoC reported by the smart shunt.
The smart shunt is in essence an amp hour (Energy) meter. It measures the energy put into the battery and the energy delivered by the battery. From that it computes an SoC. It does not measure the state of the battery directly. Therefore it has to start from an initial SoC. The SoC is set to 100% whenever it 'synchronises'. This can be done manually or the smart shunt can guess. With lead acid batteries the guesses are quite good. I do not know about LIPOs.
The smart shunt also does not know the energy loss specific to the battery, e.g. the amount of extra energy you have to put in in order to compensate for electro-chemical losses.
The upshot is that you have to both configure and synchronise the smart shunt correctly. I have a BMV and its manual explains all this. I would guess that the smart shunt manual is largely identical in this respect.
I hope this helps.
If you post the smart shunt settings and a system diagram you might get more specific help here.
Daniel
Seeing this downward trend indicates the charge efficiency is set too low in the smart shunt. What have you set it to? Try upping it 1% or 2% and see if the trend starts to go up. Ideally the charge efficiency should be set for zero trend. You can also setup the charge sync parameters but I’d start with trying to flatten that trend.
