SOC Meter on DALY 200A SmartBMS

[flemmingdjensen]

Hi,

How does the DALY 200A SmartBMS determine the State of Charge? We have seen the meter be at 100% just after top balanced 4 x EVE 280AH cells were connected

Now when we topped the battery up at 14.3V the SOC said 93%

How is this determined? Is the BMS integrating the Amps or is it just based on the battery voltage?

 

[flemmingdjensen]

 

[camdee]

To my limited understanding it is based on AMPs in/out, which does make sense. When I load the Sinowealth app on my PC and read the MCU, I get these value. So it could be a mix of thetwo, volt and amp?

 

[Pim57]

The SOC can be determined in two ways:
1. Voltage - When initialy started, or reboot with the app
2. Amperage - Integrating the amps when charging or discharging

1. Uses the Voltage chart table in the MCU system. Only accessible with the PC program Sinowealth or PCmaster
2. Uses the amps measured by the BMS

1. The voltage chart used by Daly is rather simple. It increments the voltage by 100 mV for every 10% increase. (see screenshot in the previous reply)
I changed the charttable with a better one (see attached screenshot)
Source : https://diysolarforum.com/resources/general-lifepo4-lfp-voltage-to-soc-charts-tables-12-24-48v.109/
To have this work make sure the battery is at rest for at least 15 minutes or so.

2. For the integrating part, it all depends on an accurate calibration of the amps.
And then the amps only show up when over 2.5 amps on my bms. (at least on my smart Daly 4S 100A)

100% SOC is set when the bms hits either EndOfCharge- or Over Voltage.
0% SOC is set when the bms hits either EndOfDischarge- or UnderVoltage



When my Cel Voltage is 3243 mV, Daly calculates the SOC as 37%

 

[ultrakiev]

I just figured this on my own as well. But later noticed your post.
I was able to make SOC reading more accurate than factory settings.


My custom settings on the picture.

 

[Gunther]

Hey,

I am facing a similar problem. My SOC values do not match actual state of the battery.

When I change it and write the data away to the BMS my SOC value remains unchanged.
Any idea what I am doing wrong? Why is the SOC value not adjusting?

Thanks

Gunther

 

[Pim57]

While the BT app gives you the possiblity to adjust the SOC value, it cannot write that new value to the BMS.
Same problem for the Sinowealth PC program.