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Hi !
I added the smart shunt a couple of weeks ago. Installed it according to documentation and it seems like working ok. Was running down to approx 80% and i turned the charger on up to 100% again. After that it went down to approx 80% again and I switched of everything. Saw there was zero use and the only connected consumer is only the Smart Shunt itself. Next morning it jumped up to 100%. This makes no sense as there hasn't been either consumers or chargers connected.
regards
Kurt
...by the way. The parameter "Battery starts syncronized" is switched off. It seems to be connected to the fact that the Venus Pi has been restarting. I dont know how the Venus can make this adjustment, but it does not makes any sense
Update; Did a manual adjustment of the SOC back to 83%, then a restart of the Venus Pi and the SOC went straight back to 100%. I have done several reboots before without this happen. But there were consumers running at that time.
Please give us some more details about your system and screenshots of the settings of the Smart Shunt.
Is the actual battery voltage above (greater) than the value you set for "Charged voltage" in SmartShunt settings?
After you remove the loads, the battery voltage will rise a little.
With only the SmartShunt connected, the current will be under the "Tail current" value for sure.
Once the "Charged detection time" passes (while the first two conditions above remain True), the SOC will be synchronized to 100% (it will jump to 100% if all these 3 conditions are met: voltage, current and time).
Yes, you are correct - the Charged voltage is at 13.2V while the actual voltage is 13.31V. The Tail current is set at 4%.
Batteries is 2x100ah Lifepo4
It's a bit difficult to know these values for people without deep knowledge and also was one of the boys who were sleeping in the clasroom when the teacher was preaching about mr. Ohm and his freinds. The shunt should have a preset like in the Smartsolar
Then "it's working as intended".
You have to experiment with these 3 values (starting with "Charged voltage" value).
I too have LiFePO4 batteries and so far I set the "Charged voltage" at about 3.4V per cell (I am still changing the settings after I monitor/observe my system for a while).
For your 12V system (4 cells), that would be 13.6V.
Also note that these values you set for the SmartShunt do not matter for the actual charging of your batteries. These are only for the State Of Charge calculations. The actual battery charging algorithms and values are set in MPPTs and in the inverter/charger.
Your "charged voltage" setting is 13.2V and your current battery voltage is 13.3V (the normal idle voltage of a LiFePO4 battery).
So the SOC will jump to 100% after 3 minutes (charge detection time).
You have to increase the "charged voltage" setting to something higher than the idle battery voltage. I would recommend 14.0V.
In the manual are all settings explained.
Thanks, Mathias! What about the "Tail current" as seb71 is talking about. Is it ok with 4%?
Functionality request: Put some presets like in the Smartsolar so that non-educated peoples can just choose. If that is difficult then maybe some kind of wizard so that we can take input from the specifications from the battery. It might would help on the frequency of messages at this board :)
It is charged by:
A low solar charge current (cloudy, dusk, dawn) can trigger the "Tail current" setting. So you may lower that but you have to test it. This value have to adjusted individually.
The "Tail current" is a % value of the capacity. You have 200Ah so 4% are 8A.
-> the voltage have to be over "charged voltage", the current lower then the "Tail current" and that for the time set as "charge detection time" to let the SOC jump to 100%
Hmm..... a bit complicated, I think :-). Are getting the feeling that I will be fooled by the shunt, but I will try to figure out. Thought everything will be fixed by itself in a “smart” sense, but that seems to be too much expectations.
