Growatt SPF 5000 ES-US doing strange things

I've been using the Growatt SPF 5000 ES-US 48 volt inverter since around November of 2021. It's done some strange things lately. It is connected to the Utility. I have 5 of the LifePo4 batteries. I have 2 strings of 2800 watts (14 x 200 watts in series) of panels in parallel. The output source priority is SBU. The charging is Solar only (OSO). Battery type is L1. Voltage back to utility is 20% and voltage back to battery is 40%.
The inverter seems to function according to the settings most of the time, but occasionally, it does something strange.
I've seen it go to utility to run loads when the battery is still showing over 20%--recently the batteries were at 30% when it went to utility. This happened during the night when there was no solar, so it wasn't that it had charged up from 20% to 30% with the solar and was still running the loads off the utility.
I've also seen it charge beyond 40% from the solar and stay on utility--not sure how high it went before it finally went to battery.
Just recently, the inverter used my batteries down to 1% and did not change to utility. I've never seen it do that before. I had to turn the utility breaker off and on to cause inverter to draw from utility, and then it began to power my loads, but it also began to charge my batteries, even though it was set to charge batteries from solar only. This happened several days ago, and it's been working correctly since then.
So, I don't if there is a glitch somewhere or something not programmed correctly. Any ideas?

I contacted Signature Solar tech support and explained the issues I was having. The only things they could suggest was changing program setting 21 to 20%. I had it at 5%, which he thought the Inverter begin charging the batteries from utility because they batteries got too low. So I changed it to 19%--it won't allow me to change it to 20% since program 12 is at 20%. But it still doesn't explain why it didn't use to use utility to charge the batteries when it got down to 20%. I have it set for solar only for charging the batteries, and that has worked that way until recently, now it uses utility whenever there isn't enough solar and batteries get down to 20%. I received another email from tech support: "I did a little bit of digging around and I found out that on that unit in particular, no matter what you have your charging priority to, if it is necessary it will charge the batteries from the grid. Even if you have it set to Solar only and no utility it will still try and pull from your utility if it's necessary. That was my understanding of it, Jason. Let me see if I can't find out any more about that." Well, the book doesn't say that, as far as I can find, but it use to always use utility to run my loads when my batteries got down to 20%, but batteries would not be charged until their was solar input. Now the utility always charges my batteries until they get up to the program 13 setting (which I had at 40%). I just think something is wrong with the inverter, but it didn't have these issues until recently.

Hello. This happened to me too. I believe this is related to the information in Table 2 Inverter Mode Specifications from Manuals. Low DC Cut-off SOC + 5% or Low DC Cut-off SOC + 10%. Try setting it in program 12 to 21% and in program 21 to 15% or 10%, if that doesn't work... I think that program 21 starts battery charging from Utility regardless of setting in program 14. Starts 5% or 10% SOC higher than set in program 21

But I am struggling with the following question. The weather has been very bad for several days now and I have it set in program 1 on UTI and program 14 on 050 (only solar). It has happened several times that at night, towards the morning, the SOC starts to drop rapidly for unknown reasons, this morning in 2 hours from 68% battery charge to 48% SOC??? The same thing happens when program 12 is activated. Always when program 14 is set to 050 (only solar).
The diagrams (I also use SOlarAssistant) do not show any consumption from the batteries!!! Do you have any suggestions please? I use Li batteries Growatt ARK 2.5L-A1, 10x2.5 kWh=25kWh.

Hi, I have had what I think is related to your problem. I have been running 3 inverters with AC backup, solar assistant, for almost a year. 3 times now with SBU setting, LI, 20% max SOC, back to solar 43% SOC it has drained the batteries to 1% at night. SS has suggested updating the growatt software which I have not done yet. Have you tried that? I'm wondering is solar assistant could be the problem?

Yes, I think you're right. it will be necessary to replace the Growatt software. This will take me some time. I will contact you if the described event is resolved. Thank you.
Solar Assistant is not a problem. A same curve data came form Growatt Shine software...

Can confirm your issues. running 3 in 3phase mode SBU. Sometimes the grid bypass is not triggered and the inverters suck the last percentages out of the battery. Only solution I found was to disconnect and reconnect the grid on the affected inverter. I also set grid charging to 3A so my soc is not dropping over night anymore when the SoC falls below P12 or P21. Firmware 067/068 01 104. Rported the issues to Growatt already without a solution... hopefully more people will report this so that they will correct their firmware. Further it would be great when the inverter switches to bypass that the own consumption of the inverters is not anymore taken from battery but from the grid, but I assume this is not possible...

what I found out is that when the bypass is not triggered correctly the Grid voltage differs from the inverter output voltage.

I also encountered 2-3 times in 1 yr the no reason switching to grid bypass (SUB) while the battery SOC was higher than B2AC parameter.

Only solution is to restart the inverter.
I mention I have the fw 41/40.06

For the draining battery issue, I reccomend using CGPr = CSO and ACI = 2A to cover the idle power consumption.
CSO means solar or uti if solar is not available (if there is solar >70...100W, the UTI charging stops)
AC charge occurs only when grid is connected internally (SUB, UTI).