question

Does your shunt measure and display the current when you are charging and increase the SOC. If it does not then you have the charger connection wrong. The charger negative MUST be connected to the system side of the shunt. Thrre must only be one connection to the battery negative and that is the shunt battery terminal. All other negative connections go to the system terminal on the shunt.

If the SOC is increasing during charging but not reaching 100% then your SmartShunt settings need changing. Please post a screenshot of your settings and please confirm what absorption voltage your charger is set at.

Yes, the charging current is displayed and also positive.
The discharge current for me when the solar cells are useless is displayed as -0.6A.
Then the polarity should be correct.

SmartShunt SOC gets to 100% either after all 3 synchronization conditions are met (simultaneously) or after enough energy gets into the battery.

Tail current set as 0.8% is too small for reliable SOC synchronization to 100%.

The voltages you list are also low (if your LiFePO4 is 8 cell).

What are you charger settings (Absorption Voltage especially)?

Hello,

I have set the maximum cell voltage to 3.5V in my BMS directly on the battery. I didn't want to go to the upper limit of the end-of-charge voltage to protect the battery. I also set 28V as the absorption voltage on my solar charger. Float voltage is set to 27.1V. In the Smartshunt I have the voltage when charged at 26.8V. I had now set this voltage very low to see why the shunt does not jump to 100%. Over the loading time, the display also goes to 100% at some point, but not over 100% recognition.

I also set 28V as the absorption voltage on my solar charger

This is relatively OK. It's a safe value, but the BMS might not be able to do much cell equalization (if your BMS does that).

Float voltage is set to 27.1V.

This is somewhat high. I would set Float Voltage at 26.8V.

-------

In the SmartShunt I have the voltage when charged at 26.8V.

For testing it is OK, but for normal usage it is too low. Try something like 0.2V lower than the Absorption Voltage set in the charger. So in this case 27.8V.

the acquisition time to 15 minutes

This is way too long. Try 5 minutes instead. Even 3 minutes for Summer time with clear sky.

I have the tail current at 0.8%.

This is way too low, as I wrote in my previous post. Try something like 3% - 4%.

In order for the SmartShunt to synchronize the SOC to 100%, your battery voltage needs to be above "charged voltage" for the set time, while the charging current must be below the tail current value you set.

If any condition is not met, it will not synchronize.

With your values, the voltage condition (>26.8V) is easy to met, but the duration (15 minutes) and tail current (<2.28A) conditions will not be easily met (while charging at 28V) unless you get some heavy clouds after absorption stage started.

Thanks for the information. I am currently testing the shunt with the settings you mentioned. I have now set the detection time to 1 minute to even get a reaction from the shunt. You can observe the values for one minute and see for yourself whether all the conditions are met so that the part switches to 100%. The thing is currently not working properly.

Unfortunately, I'm still having trouble resetting to 100% charge. My battery is currently fully charged and the BMS has completely switched off the current flow into the battery. A current of 2-3A flows from the battery. This is also displayed in the shunt with -2.66A. The measured voltage at the shunt is 27.98V and I set the detection time to 1min. In that case, the shunt should switch to 100% charge - shouldn't it? Unfortunately, the shunt stops at 83%. I set the tail current to 6%. I can't explain the behavior.

I have the same problem with my setup. What happens in my system is that the BMS stop charging when the battery reach 14V.

It does'nt hold the voltage at 14V but change it to float 13,5v without any absorption. That means that the shunt does'nt have time to meet the condition, even with the lowest time setting 1 min.

I think you have a simmilary problem. The solution is to set the charged voltage just below the float voltage. A flaw with that is that the shunt can syncronize earlyer than wanted.

We don't really need to discuss whether the charging parameters are suitable for a battery or not. My parameters are set that way for certain reasons and I don't want to change anything. Of course, if you set the standard profiles for the respective battery type in the shunt, the display will never jump to 100%. However, I did not use these fixed profiles but made my own settings in the expert menu. If the three conditions are then met, should the shunt jump to 100% or am I wrong?

I set 26.8V as the end-of-charge voltage and the current reading is 27.98V, so the first condition is met. I set the current to 6%. That would be 16.8A with a capacity of 280A. For me, the current is in the minus range, so the condition should also be met. The detection time is one minute and I also waited the time and the part does not switch to 100%. So where is the mistake? I can't get any further with this part.

If the three conditions are then met, should the shunt jump to 100% or am I wrong?

I set 26.8V as the end-of-charge voltage and the current reading is 27.98V, so the first condition is met. I set the current to 6%. That would be 16.8A with a capacity of 280A. For me, the current is in the minus range, so the condition should also be met. The detection time is one minute and I also waited the time and the part does not switch to 100%. So where is the mistake? I can't get any further with this part.

I already wrote that the current must be into the battery.

So at least one condition is not met => no SOC synchronization to 100%.

I've already read that. At the time I took the screenshot, some power was already draining from the battery. Before the screenshot, of course, the battery was charged and a positive current was displayed.

If the current is less than 16.8A, it should be switched to 100%. Even with a current of 10A, the shunt did not switch to 100%