I have a SmartShunt. Time remaining should be based on Ah power consumed in and out and averaged over the time specified in the settings. In my case this is set to the maximum 12 minutes (not nearly adequate). When my fridge is on I will get power drawn and time remaining will show. Once the fridge stops drawing power and the solar panels are feeding in, the time remaining disappears. Almost like it’s an instantaneous reading. If it were averaging this would not happen straight away.