B230 sometimes forgets its SOC (reset as zero) after turning it off and on again. Paired with AC200Max (the latter has updated firmware to the latest versions), calibrated regularly according to manufacturer instructions.
AC200Max reports B230’s BMS version is 1018.02, although the Bluetti app nor displays it nor
suggest an upgrade.
Is it possible to update the B230 firmware on-site, or were the “innovations” so grandiose that Bluetti engineers didn’t even try to implement the feature?
I have the same problem as you with my Ac200max and b230. I’ll let Bluetti answer you about the firmware (I have the same bms version as you) and calibration.
I’d like to tell you about my method for getting around the problem you’re having and that I’m having too: the Ac200max is connected to the b230 and switches itself off (either by itself or you switch it off). While the b230 still has power when you turn it back on, its SOC (the 5 green LEDs or on the ac200max screen) indicates that the b230 is empty… The b230 then quickly shuts down and needs to be recharged with the ac dc adapter sufficiently to prevent it from shutting down.
Methods
to prevent the b230 from shutting down when the ac200max shuts down by itself after a certain period of inactivity : if the b230 doesn’t shut down, it doesn’t “lose its SOC”. To do this, simply press the button on the b230 to switch on the “dc output”. The button lights up green. So, if the ac200max switches itself off after a period of inactivity, the b230 will remain on. So when the sun comes up and wake up your ac200max, thanks to your solar panels, as the b230 is left on it will also recharge your b230.
if you want to switch off the ac200max using the on/off button, this will also switch off the b230 and you risk losing the Soc (=0, or a value lower than the reality). To avoid this, when you want to turn off your ac200max, start by switching the blue button on the p090a expansion cable to “unlock”. The ac200max will then no longer see the b230, You can then switch off your b230, then your ac200max. Keep the blue button on unlock.
When you want to turn them back on, the blue button on the p090a cable is still on unlock. First turn on your b230, then your ac200max, and finally set the button back to lock. This will prevent your b230 from losing its Soc or recovering a soc lower than in reality.
Ps I have the impression that this problem arises because the voltage of the batteries in my ac200max (at equal charge levels, especially at 100%) is always lower than that of my b230. When you put the two batteries in parallel, the voltage of the whole is a voltage between the voltage of the ac200max alone and the voltage of the b230 alone. I therefore have the impression that when you switch on (or off) the 2 units connected in parallel, the bms of the b230 measures a lower voltage than in reality (since that of the ac200max in my case is always lower) and this lower voltage in reality leads the b230 to believe that it is less charged than in reality. This is why my method is always to isolate the ac200max and the b230 when I switch them on and off, so that the b230 measures the real voltage (reference to determine the SOC) of these cells and not a lower voltage when the b230 is combined with the ac200max.
So maybe that’s not the good explanation, but I can see that this method avoids getting a zero or too low b230 SOC.
Hi @Snips1, thank you for very detailed explanation of the workaround. I will try it.
Based on your description of the workaround, this error should probably be categorized as ‘communication failure during a user-initiated shutdown during which an erroneous B230 BMS [SOC?] reset command is executed’.
P.S. Bluetti should have included the slogan “You’ll never want to turn it off (because we ship it with bugs)” in their promo campaign.
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.
