Pylontech Us3000c going into fault mode

Morning guys.
Please assist.
I have 2 Pylontech Us3000c batteries in my system.
It has happened a few times that the master battery goes into Fault mode and leave the slave battery to supply all the load. After reset the battery works fine for n week or 2.
This happens during the night when no big loads are on the system.
Any idea why this is happening, it was working fine for about a year without any issues.

Morning Jake’s, what inverter is this connected to?

It is very difficult to say what could cause it without an “inverter” that can interpret the error message.

Did you check the SOC lights when it gives an alarm?

You can use BatteryView with a cable to connect to the battery. The Cable will cost you roughly R800

1 Like

Morning Jaco.
It is a Kodak King with BMS comms.
I also have a Pi connected to the inverter and batteries for more info and settings.
The BMS is controlling the inverter nicely.
I assume I will be able to use the cable connected to the Pi the access the batt with Batteryview.
Which port must I use?
The led indicate that the battery with fault code is at 50%, the slave keeps discharging and was at 28%

Has the bank ever been @ 100% SOC?

I would full charge each battery (disconnect 1) at a time.
Once you do that then maybe swop the 2 batteries to make the 2nd one the master?
It could be they were different SOC’s to start with and they could never get into sync…

They both reach 100% everyday at 11: 00 and stay there until the PV drops.
Was also thinking off swapping them around.

Console. Do you have the cable…

Jaco I hope that the cable that I am using to connect the batt to the Pi will work.

Would you mind posting a pic of it…

1 Like

Sorry I am at work and can only post the cable on Solar assistant site.
Hope this helps.

1 Like

4 posts were split to a new topic: Virtual Box Software

Thank you guys.
I haven’t used Battery view before.
Is it freely available to download.
Is there a place where I should look for logs or error codes?

You can find a link to the latest BatteryView just below the opening post in this thread

Note: Split thread for non-Windows OS discussion to Battery View on non-Windows OS - #4 by plonkster

1 Like

Hi there,

We provide the SMH monitoring software for thousands of systems, and we noticed that this was happening with a lot of them, so we contacted Pylontech about the issue, and after about 3 months of investigations, they gave us a firmware that supposedly fixes the issue. We have identified a few different test sites with the different combinations of batteries installed (B’s, C’s only C’s, etc), and have loaded the firmware for them. Thus far no-one has reported any issues again, so I can only assume that the new firmware works properly. Send me a message on and I can give you the batteryview software together with the new firmware ;).

Hi guys,

My first post, I am new to this group. What a valuable resource of information! Any feedback on whether this problem has been resolved with the new firmware? I am having the same problem and am contemplating my next move. My system:

Sunsynk inverter
2x Pylontech US3000C batteries (new chip - C3)

The problem started in April a week or two after installation of the system. It happened randomly, sometimes a week or two apart, sometimes everyday. My initial assumption was that the one battery was out of balance and I therefore kept them both at 100% SOC for 2 days before allowing them to discharge again. I cycle them daily and they never-ever went below 30% SOC. This seemed to solve the problem and they were running OK during the winter without any issues until a week ago.

Now the problems occurs daily, usually during the night. The SOC is usually higher than 50% on both batteries when this happens. I have swapped them around, but it is not working - the same battery faults out every time. It is the one with the older serial number (last 5 digit number is smaller than the other one). Maybe this one has older firmware?

Therefore I would like to know if a firmware update can solve the problem. Are there people who tried it successfully? If so, then which version should I use? Is there a “special” brew aimed at resolving this specific problem, or should I just update to the latest? If firmware is unlikely to solve the problem I will have to revert back to Pylontech for some advise.

Sorry for the long post and all the questions…


Hi Kippy, Thank you for the email. Here is the firmware files, the Batteryview software, as well as the recovery software (just in case you accidentally brick your BMS or load the wrong firmware, you can recover it again using that). Hope this helps: Batteryview and Firmware.

Ps, it’s a wetransfer link, so it will only be available for 7 days before they remove it from their servers, so don’t take too long to download it.

Hope this helps!
Kind Regards


1 Like

Ordered my cable today… What am I looking for in the logs?

Right… got my cable… Have Batteryview 3.0.24…

  1. The scan seems to die before getting much info about the battery with a accuracy string cannot be parsed to double ← fixed by setting regional settings to english US (was on UK before)
  2. Not sure if this info can be trusted but the battery type/size is shown correctly and firmware is shown as 1.8. Not seeing any cell voltages though and haven’t been able to see log data ← getting all the infos now. still showing v1.8

So best firmware for a US3000C? I’m guessing that conversion failure is to do with region settings?

<edit #2>
downloaded logs… have many syserror events in there… some seem to be related to high discharge current… the ones that correspond to my tripping events are usually at low discharge currents (6-9A)

Suspect though that I really should add a second battery to this paloeka setup of mine.

Yes, there is a bug in their software. For years already. Can’t believe it hasn’t been fixed yet. But it is harmless once you change your region to US or something.