GROWATT SPF 5000 ES strange charge behavior

[bai_shefa]

Hello,
I am new to the forum and I recently build a PV system.
It has two inverters in parallel (single phase) SPF 5000 ES with firmware 040 05 701; 041 05 701. Batteries 4xSLA 12V / 24Ah (They are small only to support parallel operation).
I have the following issue. When there isn't enough power from PV modules, the batteries are not charging, not even from grid. I have specified Program 14 to be SNU. The problem is that, if it is a cloudy day, or the load power is more than PV production, the inverters draw 1.6 to 2A from the batteries the whole day without charging. They even drop below specified voltage in Program 21 48.0V. They start charging after sunset. I tried different settings and restarts, but it is still the same.
I only managed to make them charge the batteries the whole day using in Program 1 SOL. But then the panels are not used to supply load if they don't have enough power. And inverters switch internal relays many times a day. Also the charge is starting again below 48V, which is very strange. I don't want the batteries to go below 51.2V. Or said in another way I want them float charge, no cycling.
Is it normal behavior? May be I am missing something in configuration.
Here is my current config:

Program	Description	Setting
01	Output source priority	SUB
02	Maximum charging current	3A
03	AC input voltage range	UPS
04	Power saving mode	DIS
05	Battery type	USE
06	Auto restart when overload occurs	DIS
07	Auto restart when over temperature occurs	DIS
08	Output voltage	230V
09	Output frequency	50Hz
10	Number of series batteries connected	4
11	Maximum utility charging current	2
12	Setting voltage point back to utility source	51.2
13	Setting voltage point back to battery mode	54.0
14	Charger source priority	SNU
15	Alarm control	ON
16	Backlight control	ON
17	Beeps while primary source is interrupted	OFF
18	Overload bypass	ENA
19	C.V. charging voltage	56.4
20	Floating charging voltage	54.4
21	Low DC cut-off voltage	48.0
23	AC output mode	PAL
28	Address setting	1
37	Real time setting---Year
38	Real time setting---Month
39	Real time setting---Date
40	Real time setting---Hour
41	Real time setting---Minute
42	Real time setting---Second
43	Battery equalization	DIS
44	Battery equalization voltage	58.4
45	Battery equalized time	60
46	Battery equalized timeout	120
47	Equalization interval	30
48	Equalization activated immediately	OFF
49	Utility charging time	0000
50	AC output time	0000

 

[BartHenry]

I think your charging amps are set to low. Look at the spec sheet for the batteries and see what the max charging amp are

 

[bai_shefa]

It is written on the batteries - cycle or float charge less than 7.2A.

 

[BartHenry]

Then set your amps to 7

 

[bai_shefa]

Both in program 02 and 11 to 7?

 

[BartHenry]

Yes

 

[bai_shefa]

I tried today with 7A. It is still the same. It doesn't charge as I think it is supposed to. This two pictures are taken in the morning:

And finally in the afternoon, the inverters totally drained the batteries
After sunset they started charging. And Warning 04 is gone.

 

[Mattb4]

Unless you have something different most AIO's can not charge from utility unless operating in AC bypass mode. They can utilize both solar and utility at that time.

 

[bai_shefa]

But I think inverters are on bypass on all 3 pictures. The line just on top of the inverter icon on the display says bypass. In the end if it is not some firmware problem, I think I will have to use external power supply (charger) or batteries will die very soon.

 

[bai_shefa]

Unless you have something different most AIO's can not charge from utility unless operating in AC bypass mode. They can utilize both solar and utility at that time.

You are right. Basically they cannot charge from grid until PV energy is not totally gone. Until that happens they power themselves from batteries.
Finally I ended up constructing external power supply. With toroidal transformer and current limited voltage regulator, set to 54V. That solved my problem.