Growatt SPF 3000TL LVM-ES: System working last night--tonight battery measures .6 volts??!

[acdoctor]

Back up and running?. Thanks for the help. I did use my panels to briefly charge the batteries and once they started reading a voltage again I connected my full array to the Growatt and everything turned on.
I found that my low voltage shutoff was set to 42V which is the default. I've never seen the reading dip below 50V, and I'm not sure at what voltage the internal BMS will shut down the batteries. I changed the shutoff voltage to 47V for the time being.
I'll check the system tomorrow morning before he sun comes up and see what the voltage is. If the issue is a single cell in the battery, I'll have to learn more about how to troubleshoot that.
Ron

No not bad cell but, misbehaving cell. Unless the cells are quality, equal capacity and well balanced some will go rogue when the pack gets into the knees in the chart below. 15 of them could have been at 2.8 volts and 1 dropped to 2.49 and tripped the BMS. At 48 pack volts you can see you only have about 9% left. I am assuming you can’t monitor your battery at the cell level through the BMS.

 

[rsi77]

No not bad cell but, misbehaving cell. Unless the cells are quality, equal capacity and well balanced some will go rogue when the pack gets into the knees in the chart below. 15 of them could have been at 2.8 volts and 1 dropped to 2.49 and tripped the BMS. At 48 pack volts you can see you only have about 9% left. I am assuming you can’t monitor your battery at the cell level through the BMS.View attachment 112056

Interesting data. No, there is no way I know of to monitor the battery on a per-cell basis. But I've never seen the voltage drop even below 50V, which should give quite a bit of leeway above the critical point. I do have the means to track voltage on the battery pack, so I might do that and see if the voltage drops lower than I realized just before dawn. I notice from your graphs that the rate of decrease accelerates once the voltage drops below 50 or so.

 

[acdoctor]

Rereading you said you have 2 batteries in series to get 48 volts. I would measure the voltage at each battery (this can be done while they are connected in series). If you can measure a difference of 0.01 volts I would charge the lower one. If you don’t have a 24 volt charger find something you can connect to the higher one as a 24 volt load and discharge it until they are equal.

Best practice is to charge each individually and hold 28 volts for 2 hours of until BMS disconnect. If BMS disconnects very much lower it will take some cycles to allow the BMS balancer to work things out. Let them set for a few hours. Connect in series and charge at 56 volts for 1 hour or until one disconnects.

You didn’t say what your charge termination voltage is. Most BMSs start cell balancing at 3.4 to 3.45 volts per cell. You need to be charging to 55 to 56 volts if they (the batteries) will handle it without one of them disconnecting on a high cell.

 

[SYKSolar]

Rereading you said you have 2 batteries in series to get 48 volts. I would measure the voltage at each battery (this can be done while they are connected in series). If you can measure a difference of 0.01 volts I would charge the lower one. If you don’t have a 24 volt charger find something you can connect to the higher one as a 24 volt load and discharge it until they are equal.

Best practice is to charge each individually and hold 28 volts for 2 hours of until BMS disconnect. If BMS disconnects very much lower it will take some cycles to allow the BMS balancer to work things out. Let them set for a few hours. Connect in series and charge at 56 volts for 1 hour or until one disconnects.

You didn’t say what your charge termination voltage is. Most BMSs start cell balancing at 3.4 to 3.45 volts per cell. You need to be charging to 55 to 56 volts if they (the batteries) will handle it without one of them disconnecting on a high cell.

I want to ask you this:
I have the GW 3K LVM ES and EG4 48V 100AH. I tried to run the BMS test software with my laptop. I referred to Signature Solar youtube video.
Signature Solar EG4-Lifepower4 BMS Monitoring Software Walkthrough (Off-Grid Solar Battery LiFePo4)
And what I got was No % capacity display on the battery display

I believed it didn't connect to the battery. Therefore I have to connect to a device - the battery. But I cannot get to the "Search Device" page (also shown on page 14 of the battery manual (see attached).
I did have the BMS Test running. I asked Sig Solar but no answer was given. Do you know how?

 

[acdoctor]

I want to ask you this:
I have the GW 3K LVM ES and EG4 48V 100AH. I tried to run the BMS test software with my laptop. I referred to Signature Solar youtube video.
Signature Solar EG4-Lifepower4 BMS Monitoring Software Walkthrough (Off-Grid Solar Battery LiFePo4)
And what I got was No % capacity display on the battery display

I believed it didn't connect to the battery. Therefore I have to connect to a device - the battery. But I cannot get to the "Search Device" page (also shown on page 14 of the battery manual (see attached).
I did have the BMS Test running. I asked Sig Solar but no answer was given. Do you know how?

I don’t have that battery but did you verify your com port in the computer? Were you connected to the growatt at the time? If so you should be using a different address than #1. The growatt will use it. You could start a thread and call it “connecting EG4 to laptop “ I believe you will get some help. A lot of members have the eg4 s now.

 

[rsi77]

Update: I charged my batteries to full charge, and now the system seems to be working quite will. I have them powering a load now, so I will watch to see how well they keep their charge over time.