@J0hnny Please update the firmware version to 1022.09, and then do several times of cycles one by one to test.
I would like to ask a Bluetti engineer whst is the limit of B series batteries attached to each expansion port of the AC300 and AC500 controllers. Maybe all of the batteries can be serial connected to just one port since they are actually in parallel, and the firmware will recognize and assign a battery pack number to each.
I did that and the AC500 would not turn on. Pressing the on/off button did however turn on all the batteries, so electrically they were all connected and communicating with the AC500.
Hello @BLUETTI_CARE,
hello @BLUETTI,
after I did the update to 1022.09 I watched it longer.
unfortunately the batteries are still drifting apart (see pictures)
the pictures are always from a different day and deviate a little more than desired.
I’ve also let the batteries run out twice and fully charged them to 100%.
01.07.2023
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29.06.2023
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28.06.2023
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23.06.2023
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Best regards
Rainer
The uneven discharge is also so extreme with my AC200MAX.
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I reconnected all the cables today and will keep an eye on it.
What I noticed is that battery 3 is always the first to be charged since the update.
at around 450 watts, this battery always starts charging first and the rest only comes with more solar power.
current
battery
total 69%
2=58%
3=88%
4=71%
5=62%
Before the update, all batteries were charged the same without these discrepancies
@J0hnny Please connect the battery one by one, then empty the battery and fully charge it without interruption. The age of the battery will also affect the charging and discharging speed.
Hello Bluetti_care,
Yesterday I discharged all the batteries individually on the AC500 and then started charging the batteries individually via the AC500.
I noticed that 2 batteries were fully charged at 91% and the display was corrected to 100%.
Unfortunately, I had to find out again today that the batteries drift apart again after a short time.
The batteries are only about 6 months old.
Best regards
johnny
Yeah, much the same problem; charging all of them up to 100% everyday seemed to align them and not have as much of a difference. The newest battery I added is always the last one to come out of standby and start discharging.
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I did the calibrtion drain and recharge thing with all 4 batteries, and I noticed it takes longer to recharge the whole battery bank now. I’m thinking some were getting to 100% before they were really fully charged, which is the reason to calibrate them. So now the programming recognizes there’s more battery capacity to charge.
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It’s not the batteries themselves that need calibration, but the charging programming. With lead acid batteries, their voltage would tell you their SoC. That doesn’t happen with Lifepo4 chemistry, as the voltage stays near constant until the very end before it falls over a cliff.
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Google “calibration B300s” or similar for an excellent video on this.
Discharge them all until the ac500 SHUTS DOWN, but don’t let the batteries stay discharged for too long.
They say to discharge them with a constant load. I didn’t want to use a heater because it might run too long, so I used a window air conditioner with the lowest coolest temp, to minimize the compressor cycling on/off.
You need a constant recharging source so just use the wall outlet, and disconnect all loads before recharging. It took roughly 6 hours (I didnt time it).
The AC200MAX has the same problem with the batteries as the AC500.
I say, you can calibrate the batteries as long as you want, it will not change.
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(Sometimes the external batteries (with the MAX also the internal) are almost evenly charged - discharged,
then again completely unevenly.
Bluetti has provided me with an update for the BMS, only the BMS is actually “only” there to monitor and control the individual cells within the batteries, nothing will change).
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The problem is the control software in the main box,
which regulates the charging and discharging of the external batteries as a whole.
Hello @BLUETTI_CARE ,
here are the pictures of what I noticed.
the same battery is always charged first, which explains why it always has the most charge. always at about 250-400 watts then come
the other batteries only when more solar power is fed in
Hello @BLUETTI_CARE,
Hello @BLUETTI
Is there already a solution?
since the update, loading doesn’t work so well with the new software update.
Since only one battery starts charging first, I end up destroying the others (see picture: SOC)
this should be fixed as soon as possible.
Best regards
@J0hnny If all the batteries can be fully charged or discharged when you connect AC500 with 4x B300S in the case that you had done the battery cycle for the battery one by one?
Yes, all batteries can be charged to 100% if all 4 are connected at the same time.
All batteries can also be charged individually to 100%.
they all go to 0% if you teach them and you constantly discharge them.
@J0hnny If so, that means that there is no problem with all batteries. The battery voltage between the battery packs may be different. In the case of parallel connection of different DC voltages, the battery pack with higher voltage discharges more and the SOC drops faster when discharging; when charging, the battery pack with lower voltage has more charging current and SOC rises faster. Even if there is a difference in power, it will still be fully charged to 100% or fully discharged to 0% in the end.
Hello Bluetti,
I agree with you. but isn’t it unhealthy for battery 2 and 5 if they are at 0% and the other batteries still have 50%.
I mean because of deep discharge etc.
@J0hnny I checked with the tech team, when the battery charge reaches 0%, it will not be discharged, and there is still a margin in itself, with over-discharge protection.