Found it in the B230 manual:
Can the unit be upgraded?
When B230 has been connected to AC200Max, the firmware including ARM,
DSP, IoT and BMS can be upgraded online through OTA via BLUETTI APP.
I’m excited to discover the IoT in the B230. However, the question remains. Is the claim ‘When B230 has been connected to AC200Max, the firmware including ARM, DSP, IoT and BMS can be upgraded online through OTA via BLUETTI APP’ true or misleading to the buyer?
Just found another Easter egg from Bluetti in the manual. Bluetti team, do you read your own manuals?
@Serge Have you done charge/discharge cycle yet? Please provide us the SN and software version number of AC200MAX.
To be clear, it is not a matter of upgrading the B230 firmware to solve the problem. Originally, this is related to the control strategy of AC200MAX, and has nothing to do with whether there is B230 firmware or not.
There is another problem if you use two B230 batteries. With my AC200MAX, one battery (no. 3) is hardly discharged at all, it will not go below 80%. This battery is also always charged preferentially.
(Sometimes it is discharged a little more)
Yes, all three batteries have already been completely discharged and recharged, and I have already swapped the two B230s with each other, but nothing has changed.
It’s always the same B230
And the latest BMS firmware for the AC200MAX is installed.
If there is no solution to this problem, please repair or replace this battery.
There is a four-year warranty, the battery is from 2022.
Picture,
at the beginning all batteries were charged to 100%.
Have you done charge/discharge cycle yet?
Many times. I’ve explicitly said ‘calibrated regularly according to manufacturer instructions’ in the very first post.
Please find S/N and software versions below.
I updated the firmware to the latest version using the Android Bluetti app a few weeks ago, hoping that would solve the unstable SOC after shutdown/on, and after the update I charged/completely discharged/recharged to 100%. Firmware update cured SOC of AC200Max but had no effect on the B230’s Alzheimer SOC.
Yesterday I charged my AC200Max+B230s to 100%, then verified once again they are at 100% after turning them off. Today I turned them on to get a snapshot of S/N and software revision, and got a surprise - the B230 says 81% SOC. Turned them off and back on to see that the B230 now says 64% SOC. It will then take a 30Wh charge (2 minutes) and report 100%.
Did Bluetti IT try saving the SOC in NVRAM? That would probably help.
P.S. I had to make a decision a month ago when I urgently needed to increase battery capacity. Now I’m glad I didn’t go down the Bluetti rabbit hole then, but chose a battery and inverter system that isn’t locked into one TM, mixes batteries seamlessly, mounts and increases capacity at will (just look at Bluetti’s zoo of incompatible batteries).
@Serge
there may be similarities here with the B230 batteries,
perhaps my problem battery is also displaying an incorrect SOC.
Have a look here, the same problems as with your B230 batteries
Hi @Serge, Thank you for your feedback. Please note that the B230 does not support firmware upgrades.
However, there is a new BMS firmware available for the AC200MAX that addresses the issues of large power discrepancies between the AC200MAX and the B230, as well as significant SOC changes on the B230 after a restart.
Our IT department will push the latest version of firmware to your machine in 24 hours. Please upgrade it tomorrow.
When upgrading, please disconnect the AC200MAX from the B230 and upgrade the AC200MAX separately. Meanwhile, please do not load any device when upgrading it.
After the upgrade, you can reconnect the B230 with the AC200MAX and recalibrate them together.
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 @jockel66’s kind help and specialty analysis.
This is a very good news. Can you also push this firmware on my AC200max ? I have the same issue.
AC200M2220001141724.
Thanks
Hi @Snips1, Yes, we’d love to help you.
Please tell us your AC200MAX’s firmware version.
Then we will apply for further service for you.
Hi @Snips1, Thank you for getting back to us so quickly.
Our IT department will push the latest version of BMS to your machine in 24 hours. Please upgrade it tomorrow.
When upgrading, please disconnect the AC200MAX from the B230 and upgrade the AC200MAX separately. Meanwhile, please do not load any device when upgrading it.
After the upgrade, you can reconnect the B230 with the AC200MAX and recalibrate them together.
Please follow the steps below to recalibrate it:
You can click this link for reference.
Please let us know if it does 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’ve updated the BMS firmware to 1017.07 and will give recalibration a try.
Could you release my concern on the described procedure? At the moment the local electricity is highly unstable, being shut down at least twice a day.
Basically, this was the reason for purchasing a Bluetti power plant as a backup power source. From a Bluetti perspective, the correct way to use Bluetti equipment in my scenario would be to (choose one):
I did a lot of testing this weekend, with the new firmware, turning off and on my Ac200max with my b230 connected, at different SOC levels… And my B230 never “lost its initial SOC”. So that’s a big improvement! Thanks a lot! 
Hi @Serge, Our new firmware has proven successful in resolving similar issues and should completely resolve the problem. There’s no need for a repair.
You can also test the new firmware yourself to see how it performs.
If you plan to use the device only a few times a year, please ensure you charge it every three months to maintain the battery at around 50%. Long-term inactivity can negatively affect battery maintenance.
Hi @Snips1, Thank you for letting us know.
I am glad to hear that! Please feel free to contact us if you need more help.
Hello @BLUETTI_CARE
I have two AC200Max and one B230, and you released the special firmware for one of my AC200Max to fix the SOC issue on my B230. This firmware works very well.
For various reasons, I now need to connect my B230 to my other AC200Max, which doesn’t have the special firmware to fix the SOC issues on my B230. Can you release this firmware for my second AC200Max? Data Below. Thank you very much.
Hi @Snips1, thank you for getting in touch with us.
We would like to help you. Now, I have applied to push the new BMS to your second AC200MAX.
Our IT department will push the latest version of BMS to your machine in 24 hours. Please upgrade it tomorrow.
When upgrading, please disconnect the AC200MAX from the B230 and upgrade the AC200MAX separately. Meanwhile, please do not load any device when upgrading it.
After the upgrade, you can reconnect the B230 with the AC200MAX and recalibrate them together.
Please let us know if it does help.
Thank you for the firmware, I updated my AC200max and it works much better with my B230 (after a recalibration). Thank you!
Hi @Snips1, thank you for letting us know, we are glad to hear that!
Your experience in resolving this successfully can also be of great help to other users facing the same problem.
Hello @BLUETTI_CARE
I seem to have the same problem as ther have seen on the chat.
I have an AC200MAX and 2 B230’s connected.
The SOC on one of my B230’s seems to go from 100% to 0% within 10 mins of being connected to a 12V fridge. That is with the B230 on it’s own. When it shows 0%, I can then recharge via the Bluetti 400W charger (nothing else connected, no load). I will draw 400W for about 10-12 minutes, then say it is at 100%.
I have tried a calibration several times now.
That was with the B230 on it’s own. Charge to 100%, then discharge. This has not corrected the SOC issue.
See attached my firmware.
Could you push the new versions to my AC200MAX, to see if that helps.
Thanks in advance.
I have two AC200Max and one B230, and you released the special firmware for one of my AC200Max to fix the SOC issue on my B230. This firmware works very well.
For various reasons, I now need to connect my B230 to my other AC200Max, which doesn’t have the special firmware to fix the SOC issues on my B230. Can you release this firmware for my second AC200Max? Data Below. Thank you very much.
Grahame.
