I have an AC500 with 4x B300S. I’ve only been using the power station for a few weeks. Now I noticed that the state of charge of the batteries are extremely different.
total charge=50%
battery 1=65%
battery 2=70%
Battery 3=27%
battery 4=38%
I have the SOC at 30% and am now “afraid” that e.g. battery 3 will be deeply discharged because it is already extremely different.
what can you do about it?
The batteries are each connected in series on the two terminals of the AC500
Info:
BMS version 1022.08
DSP version 4047.03
ARM version 4048.02
HMI version 6052.04
Having four expansion cables and two expansion battery ports, I suggest swapping cables and batteries between the two ports in order to localize the weaker charging port or the bad expansion cable. Many others and myself have done this procedure and have localize the bad component or resolved the problem, since the AC series of controllers and their B series batteries are sensitive to the expansion cable connections. I hope Bluetti eliminated this problem with the new AC900 model.
I just added a 4th B300s and twice now, after topping all the batteries off at 100%, this new battery stays in “Standby” mode while the other 3 discharge. Today, the other 3 were in the 70% range while the new battery stayed at 100% on Standby.
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Yesterday I powered everything down and when it came back up the new battery started discharging normally. So I did the same thing just now but I also swapped some cables around while it was off. I turned ONLY the new battery back on and it started discharging like it should. If it happens again a 3rd time tomorrow I’m going to need some help.
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It sounds like the software has a problem with 4 batteries. When I had 3 they all charged/discharged at almost the same rate.
When I swapped cables around, the Head unit would not turn on (all the battery green buttons were lit.) So I swapped cables around again and then the Head unit came on. I “daisy chained” them but I was using only one of the Head unit ports; it didn’t like that.
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I now have 2 batteries on each of the Head unit ports.
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.
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%.
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.
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
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.
