Smartshunt Status

DIY
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1

The Smartshunt is an excellent add-on to a system to keep track of SOC. The problem is with the synchronisation you have no way of knowing if the 100% sync has happened successfully or not.

I think my system has met the three criteria but I will now have to create a battery discharge situation and check the Victron SOC with the Fogstar SOC display to be sure. There is no other indication of the Smartshunt status even, on it’s own webpages.

I would like to suggest a couple of changes:

  1. Could we have a Modbus (and possibly an MQTT topic) that reflects the status of the Smartshunt? What I am thinking of are values that say: “Synch Requested”, “100% Synch success” and “Using Manual Value”. Adding the voltage and current levels would be nice too. It would make checking the Smartshunt almost a foolproof process.

  2. There is an option to manually enter the current SOC value. This value is accepted and is displayed as the current SOC by the system. But, the value remains static at that value and does not track with the actual SOC. Why not do a basic calculation and then “force” the system to synchronise from that point? Once a valid 100% sync situation is reached the system can run as a normal synchronised system.

2

Hi @dgoadby !
The Smartshunt will tell you when it has last made a full charge and therefore reached 100% if your settings are right for that. From there on it will keep track of your SoC. If everything works right there should be no need of a manual sync - then you rather should check your settings and correct them.

Meddling with this in a different way would contradict the purpose of the Smartshunt.

Example from my system:

image
image1206×2622 377 KB

Hope this helps a little.

3

Older Fogstar BMS are absolute rubbish if you have small charge/discharge currents. They don’t see anything below 1 amp so easily get out of synch with a smart shunt. My system has a constant draw of 3/4 amp which is seen by the Shunt but ignored by the BMS. There have been times during the winter when there is not a lot of solar where the Fogstar is reading 100% and the Shunt reads 60%.

I contacted Fogstar about this and there answer was to ignore the SOC from the BMS which I now do.