Pylontech going offline

[jgh]

2x Pylontech US3000C
Solis hybrid inverter

A couple of days ago the Solis website gave me a status for the battery of "Warning". After a while it went back to "Normal".
Yesterday, it went to "Fault" (and emailed me, too), at 11:20 local. SOC was about 93% at the time.
I left it alone for a while; it was still supplying power and occasionally taking a short low-rate charge
(I was monitoring the BMS charge limit via the Solis website).

After an hour or so, went up to the loft; the older of the pair of batteries had only a red LED. The newer one
(data master for the stack) looked normal with a whole suite of greens. Turned the stack off and wiggled all the connections,
turned it back on and all looked good... until 14:10 when it tripped out again.

The faultcode as reported by the Solis website is :- OCPL.BMS(33293)
Can anyone give me a better hint for the fault detail than "the BMS reported a problemt" ?


Operating conditions: these are installed in my loft. It's been pretty cold the last few days and nights;
probably down to zero Celcius overnight, if that's a factor. This time of year there's little PV input
(there was actually a few hundred watts that day, hence the high SOC) and I charge to 100% overnight from grid.

The older US3000C was installed last March, the second one in September.
SOH for the older one alone is 99%, for the stack of both 100%.

I'm currently running on only the older one (since midafternoon yesterday), and it seems fine.
If that continues I'll swap to only the newer one tomorrow, and try that for a couple of days,
then back to both...

 

[rpdom]

Much under 10°C and your batteries will stop charging.

Finding out what the fault is could be tricky. The inverter may not be able to get the details.

Pylontech have some software called "Batteryview" (I think) that you can put on a laptop and plug it into the Console port on one of your batteries and get a load of information from them. It does need a special cable though. If you know what you are doing you can splice together a USB serial port and an ethernet cable instead. Only three pins are used.

The first port of call should be your supplier or Pylontech support.

 

[jgh]

The units run individually worked fine, so I went back to both.

Had two more events - and both self-resolved. I'm thinking it's an overvoltage trip in the BMS,
given that all the events have been under a slow charge at near-full SOC (is that estimated by the BMS,
or by the Solis?). Logged max of the "BMS battery voltage" for today's and yesterday's was 53.14 so
that's 3.54 V /cell. Doesn't seem excessive, but not much point trying to push more energy in either.

The one yesterday cleared it's alarm when I pulled about a kilowatt for ten minutes, Today it was
only the house base load, probably no more than 350W peak.

So my guess it that at low temperatures either the cell chemistry makes for higher voltage, or
the BMS drops its voltage limit. I'm happier now I've seen it resolve on its own.


I can't run Batteryview, having no Windows systems in the house. I did see a suggestion somewhere
that one could just talk to a commandline via serial to that port (but no details of commands).
Perhaps I'll try that some time in the future.

 

[rpdom]

53.14V seems a bit high. I get occasionally get 2015 alerts when it's below 53.0V. Also 3.54 V/cell is high for LFP.

I can't run Batteryview, having no Windows systems in the house.

For some reason that doesn't surprise me. Have I run into you somewhere else? Perhaps with 8-bits?

I did see a suggestion somewhere that one could just talk to a commandline via serial to that port (but no details of commands).

Yes, you can do that. I made an interface board for a Raspberry Pi that connects to the batteries with a standard ethernet cable. I haven't worked out what all the commands do, but I can get some stats and info using a terminal.

pylon>bat 1
@
Battery  Volt     Curr     Tempr    Base State   Volt. State  Curr. State  Temp. State  SOC          Coulomb     BAL
0        3317     -820     9800     Dischg       Normal       Normal       Normal       99%         48231 mAH      N 
1        3317     -820     9800     Dischg       Normal       Normal       Normal       99%         48232 mAH      N 
2        3317     -820     9800     Dischg       Normal       Normal       Normal       99%         48231 mAH      N
3        3317     -820     9800     Dischg       Normal       Normal       Normal       99%         48231 mAH      N
4        3319     -820     9800     Dischg       Normal       Normal       Normal       99%         48232 mAH      N
5        3317     -820     10000    Dischg       Normal       Normal       Normal       99%         48230 mAH      N
6        3317     -820     10000    Dischg       Normal       Normal       Normal       99%         48231 mAH      N
7        3317     -820     10000    Dischg       Normal       Normal       Normal       99%         48232 mAH      N
8        3316     -820     10000    Dischg       Normal       Normal       Normal       99%         48232 mAH      N
9        3317     -820     10000    Dischg       Normal       Normal       Normal       99%         48230 mAH      N
10       3317     -820     9600     Dischg       Normal       Normal       Normal       99%         48231 mAH      N
11       3317     -820     9600     Dischg       Normal       Normal       Normal       99%         48232 mAH      N
12       3317     -820     9600     Dischg       Normal       Normal       Normal       99%         48232 mAH      N 
13       3317     -820     9600     Dischg       Normal       Normal       Normal       99%         48232 mAH      N 
14       3317     -820     9600     Dischg       Normal       Normal       Normal       99%         48230 mAH      N 
Command completed successfully
$$
pylon>

 

[SeaGal]

is that estimated by the BMS, or by the Solis?

By the BMS.

Logged max of the "BMS battery voltage" for today's and yesterday's was 53.14 so
that's 3.54 V /cell. Doesn't seem excessive, but not much point trying to push more energy in either.

Seems high to me. Personally I only charge to 3.45V per cell. The 3.54V you mention... are you measuring actual cells, or just dividing the battery voltage by 15? If the latter, you are assuming they are perfectly balanced.

IMHO, the BMS should report 100% to the Solis once it reaches what is configured as the maximum. This will cause the Solis to stop charging.

In my books, the battery's BMS is not working correctly if it is reporting an over-voltage condition before reporting 100% SOC. hence suggest you follow up @rpdom's suggestion...

The first port of call should be your supplier or Pylontech support.

 

[jgh]

Have I run into you somewhere else? Perhaps with 8-bits?

Unlikely.

Yes, you can do that. I made an interface board for a Raspberry Pi that connects to the batteries with a standard ethernet cable. I haven't worked out what all the commands do, but I can get some stats and info using a terminal.

pylon>bat 1
@
Battery  Volt     Curr     Tempr    Base State   Volt. State  Curr. State  Temp. State  SOC          Coulomb     BAL
0        3317     -820     9800     Dischg       Normal       Normal       Normal       99%         48231 mAH      N
1        3317     -820     9800     Dischg       Normal       Normal       Normal       99%         48232 mAH      N
[/QUOTE]
Sounds like I'll be feeding a network cable up to the loft.  I guess the "Volt" column is actually mV;
any idea on the "Tempr" (temperature in deg C / 1000, maybe)?

 

[jgh]

The 3.54V you mention... are you measuring actual cells, or just dividing the battery voltage by 15? If the latter, you are assuming they are perfectly balanced.

The latter, so fair point.

 

[rpdom]

Sounds like I'll be feeding a network cable up to the loft. I guess the "Volt" column is actually mV;
any idea on the "Tempr" (temperature in deg C / 1000, maybe)?

The battery Console is RS232, so you'll need to connect the cable to some sort of adaptor.

Yes, Volt is mV, Curr is current in mATempr is cell temperature in millidegrees C. 9.8°C seems about right for the battery at that time of day.

I had network cables running through my loft, so I hooked up a couple of spares to sockets up there. One for the Ethernet to RS485 Modbus adaptor to monitor and control the inverter, the other has a Raspberry Pi Zero which monitors the temperature and connects to the batteries. I powered both by using passive PoE adaptors feeding 12V up the line from the patch panel. The Pi has a tiny 12V to 5V converter which I managed to fit inside the USB ethernet adaptor.

 

[jgh]

Yup, just gotten one of the Waveshare units, described as "2-Ch RS485/RS232 to POE Ethernet" by Amazon.
The documentation is... difficult. It seems to have a single IP with a single port for the active
(as opposed to web-config) access; I'm stumped so far on how to get to the other port, but it
should do for the battery console.

 

[jgh]

The battery Console is RS232, so you'll need to connect the cable to some sort of adaptor.

OK, I'm talking to it (it works a whole better when I don't use a bad pinout for the Wavetech).

Presumably the BAL column is something like "balancing in progress" rather than "in good balance state";
mine are also all "N".

 

[rpdom]

Presumably the BAL column is something like "balancing in progress" rather than "in good balance state";
mine are also all "N".

Yes, I've seen mine balancing when at around 93% charged. Some cells had "Y" and some had "N".

 

[jgh]

There's a good chance it's a unix-like shell in there; it accepts "bat 1; bat 2" as a single command line.
The "log" command can take an argument limiting the number of entries display; default and max is 3.
The "info" and "soh" commands take a battery number.

 

[jgh]

First anomaly noted:

6        3492     4092     10300    Charge       Normal       Normal       Normal       94%         68446 mAH      N
7        3471     4092     10300    Charge       Normal       Normal       Normal       92%         66990 mAH      N
8        3562     4092     10300    Charge       High         Normal       Normal       99%         72087 mAH      N
9        3477     4092     10300    Charge       Normal       Normal       Normal       93%         67718 mAH      N
10       3463     4092     9900     Charge       Normal       Normal       Normal       91%         66262 mAH      N

The stack went to all-discharge state shortly after that point; all voltage states Normal - and with two cells
in that battery at 95% & 98% SOC, remainder 100%
The visible log entries are "coulomb full", "start discharging", "coulomb normal".

And (in the time taken to type those in) another check shows all at 100%.

 

[jgh]

Just had another one - and the temperatures are +14 C so that can't be the issue.
It self-corrected after half an hour.

Some more hunting found me this: https://diysolarforum.com/threads/pylontech-battery-fault.38451/
and this: https://electricianforum.co.uk/threads/solis-error-2015-bms.56307/

I might try the suggested tweak from the latter (though it doesn't seem to be exposed via the soliscloud
so it'll be another loft clamber).

 

[JMACK61]

Much under 10°C and your batteries will stop charging.

Finding out what the fault is could be tricky. The inverter may not be able to get the details.

Pylontech have some software called "Batteryview" (I think) that you can put on a laptop and plug it into the Console port on one of your batteries and get a load of information from them. It does need a special cable though. If you know what you are doing you can splice together a USB serial port and an ethernet cable instead. Only three pins are used.

The first port of call should be your supplier or Pylontech support.

I have that Batteryview software. The RJ11 port which is 4 wire, the two outer wires are ground hook them to 5 on your female DB-9 hook the inner two connections of the RJ11 to 2 and 3 on the DB-9. Swap them till you get something. Baud is 115K 8N1 if computer is new and no DB-9…you need a USB to DB-9 cable. Battery view is good for looking even windows hyper-terminal works. Once that cable is right and the speed is set “pylon” will be your prompt, type “?” To get the stand commands and start troubleshooting the problem. Guess this comment is for Radom.

 

[jgh]

I have that Batteryview software.

Does it say anything separate for the logs of slave batteries in the string?

 

[jgh]

Finally spotted a relevant log entry:

log
@
 Index   : 31   
 Time    : 24-02-23 22:10:22
 ModID   : BMM
 Code    : 5
 Info    : The voltage of device is too high.

 Index   : 30   
 Time    : 24-02-23 22:10:06
 ModID   : BMM
 Code    : 2173
 Info    : The device start charging.

 Index   : 29   
 Time    : 24-02-23 22:09:16
 ModID   : BMM
 Code    : 0
 Info    : The device start discharging.

no clues which device or sub-device it means. This is with voltages dropped in the Solis per
https://electricianforum.co.uk/threads/solis-error-2015-bms.56307/ - so that hasn't helped.

Stack voltages, 30s samples :-
View attachment 197772