Issue with B300S instantly charge from 23% to 99% and istantly discharge from 50% to 0%

I have an AC500 with two B300S. One of the B300S is probably defective, basically I can’t fully charge it and when i discharge it, it jumps from 50% to 0% in matter of seconds.
Down below some in-depth explanation of what I’ve tried to do.

  1. do you have a Bluetti supports phone number where i can contact you, if yes can you give it to me?

  2. I’ve updated the firmware IoT(v9041.03), ARM(v4048.02), DSP(v4047.06) and the two BMS (v1022.09)
    I’ve recharged both of the batteries with the 230V ac cable, but one B300S (probably defective) went from 23% to 99% in 10 seconds, while the second one was still on 17% charge

  3. I’ve charged them at 100% (but i highly doubt that the defective one was really at 100%) and enabled again the AC output to let my house be powered by the Bluetti, but the defective battery jumped from 50% to 0% in matter of seconds giving the error “Cell low voltage protection”

What should i do?

@Baldarello Have you tried to calibrate the machine?

First discharge the machine to 0%, then charge it to 100% via AC. During this time it needs to be charged continuously, with no loaded. Please try to cycle twice.
Please connect AC500 to B300S one-to-one separately to perform battery calibration.

Please let me know if there is still a problem with the two B300S after they have been power cycled separately

@BLUETTI Already tried 3 times to do that, yesterday evening the last time.
Battery jumped from 70% to 0%, then recharged from 0 to 23% draining only 600w, and after done the 23% jumped again to 100%
Only the defective B300S was connected

Okay. Please provide the SN and all firmware version numbers for the AC500 as well as the problematic B300S. I will submit it to the engineer for analysis.

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@Baldarello SN code consists of 13 Arabic digits, can you check it again?


Here I am again, since the support via email are not responding me anymore:

  1. after telling me to upgrade the firmware ignoring the fact i’ve already told them i have the latest version available;
  2. after telling me to do 2 cycle of charging and discharging ignoring the fact i’ve already done it multiple times also charging with AC 230V and tried also with PV.

I will add here 2 videos of what happens to my B300S during charge and discharge still looking for help. Or help me to start the RMA procedure.

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@Baldarello I have checked with the customer service department. This order belongs to IGG Crowdfunding. The crowdfunding department has taken over the processing. And will get back to you within 48 hours. Please watch for an email from Thanks again for your understanding.

Other than your error message, it’s “normal” on mine to take a moment (sometimes several seconds) for the true readings to come up. It will sometimes show a wide SOC difference for my two batteries, but within a few seconds the true readings will appear and be within a few % points of each other. My guess is the software is kind of slow to catch up.

I’ve never performed a battery calibration and wasn’t aware it needed it. Guess I should do it. I kind of hate seeing it draw 1.6 Kilowatts from the wall outlet when my PV panels produce almost 2 Kilowatts. I might use the panels as long as there are no clouds. Currently the batteries get to around 30% at night but by 11am it’s back at 100% with a constant 230 watt load.

Hi. thanks for your response @St8kout .

Did you actually check my videos?
How can you say this is normal?
Jumping from 21% to 100% while recharging and then from 70% to 0 while discharging?
Especially when i use both B300S connected in the same time, both charge up from 0%, but one does the jump and the other goes up normally.
Both discharge from 100% but one jump from 70% to 0% and the other goes down normally.
I can use only 20% of the 3000w of the defective B300S is not a software bug showing wrong numbers.
It’s not normal at all and it’s not only the software because the same thing happens from the AC500 display B300S 20% to 100% in seconds from AC500 display - YouTube as you can see from this video.

They finally started an RMA, I’ve sent back the faulty battery the 24th of April.
I’ve got no more news on it yet. I’ve sent more emails but got 0 answer.
Is there any way to understand what they are doing? Or at least know if i will recevie a new working unit anytime soon? @BLUETTI

@Baldarello Your feedback has been received and I have forwarded it to the crowdfunding department for them to expedite your situation. Please don’t worry they will help you handle it properly and will usually get back to you within 48 hours.