I have AC500 with one B300S and I’m experiencing problems with SOC. For example, sometimes the system charges (from solar) with 500W for an hour, but SOC stays almost unchanged. Then later, SOC suddenly jumps up to 100% or so. The BMS is v1022.09
Would like to update the BMS to the latest version, which was mentioned here:
The serial number is AC5002241000496080
Please push me the latest version, thank you!
Hi @southside, Thank you for getting in touch with us.
We have pushed the new BMS firmware for you. Please upgrade the firmware tomorrow. Please do not load any device when upgrading it.
Please update each battery one by one, connecting only one B300S battery at a time.
After that, please try to complete the cycle of discharge and charge to correct the SOC. The problem will be resolved.
Please follow the steps below to recalibrate it:
You can click this link for reference.
Please let us know if it does help.
Thank you for pushing the Update! The BMS on my system is now version 1022.14
Then I performed the discharge / charge steps. So far, everything looks okay again.
I will monitor the system for some time and then let you know the result.
Hi @southside, Thank you for your update, we are glad to hear that!
We hope everything goes smoothly from here!
Please feel free to contact us if you need our help.
By the way, please note that if you need my assistance, please @BLUETTI_CARE, otherwise, I might not see your message and be able to help you promptly.
Hi @BLUETTI_CARE, I did the SOC calibration and want to share some results. I am using HomeAssistant to control the AC500 and added two screenshots with measurement results, as following:
In the beginning, the system is charged via solar input. Now watch “Total Battery percent”:
At postion (1) the SOC reaches 99% and stays at 99% for more than 1 hour, although solar continues to charge (not okay).
At position (2) the SOC reaches 100% and the AC500 shuts down solar charging
Then 2 hours later, I started to discharge with 2300W (10A * 230V)
At position (3) the SOC reaches 1% stays there for 20 min, while continuously discharged (not okay)
At position (4) the SOC reaches 0% and the AC500 switches AC-Output off then shuts the system down
20 minutes later I started to charge the systen via AC-Input with 1150W (5A * 230V). Solar charge is disconncted.
At position (5) the SOC reaches 99% again and stays there for over an hour. However the AC500 reduces charge power to 850W.
At position (6) the SOC reaches 100% and the AC500 stops charging via AC-Imput.
I found these results quite interesting and wanted to share this. Hopefully the SOC is calibrated now correctly. I will send a followup in some time.
Hi @southside, Thank you for sharing this. I believe it’s normal for the battery to remain at 99% for about an hour. When the power station is nearly full, the BMS (Battery Management System) enters a trickle charging mode and limits the charging speed to prevent overcharging, which can be harmful to battery lifespan.
We look forward to your further updates.
