Growatt Inverter Repairs

[CJSOLAR]

Good Day All.

I bought (2x) Growatt SPF 5000ES inverters the other day for 2 different clients. The inverter runs with (4x) 100Ah AGM deep cycle batteries 48V back-up. Also I installed (4x) 455W half cell canadians.
After successful installations and correct settings on inverters I found that one of the inverters both the same settings operating a bit different.
So the settings was as follows: Charge Solar first, Supply priority Solar first then if not efficient utility then battery. Battery selected on "use" to set battery Bulk charging of 57v and constant float charging 54v. So on the LCD screen it shows/indicates that there is pv charging to the 57v for a few min and then after to constant 54v. When it reaches the 54v the invertyer is using the bypass utility and using battery at the same time. the voltage of the batteries drop to about 51v and the charging through the pv panels again up to 54v. So it continue doing the whole time. The second client inverter does not do this at all.
So I went to different forums to search if this happen to anyone at all. A LOT of people having the same issues, even with lithium back-up. Most of them replied to update the firmware's and some find that it works(Battery on stand by when fully charged). So I thought I was very clever....... got all the programs and software from the net.....At first I thought whoow this is working as the inverter reacts on the update, but.....after the first bin file the LCD screen went of and indication lights dancing around. The BMS communication card also making a on and off fast clicking sounds.
I tried almost everything regarding firmware but no luck. I can not find anyone to check or repair this unit.
Now I am desperate, is there anyone on this forum whom can please assist me on this, will highly appreciate this.
Thank you
Johan

[Dave A]

From what I have read on Growatt, tech support has been coming direct from China. Apparently they do respond though.

[Dave A]

May I say you were pretty brave doing a firmware update. Looking at the problem, I am inclined to believe it is somewhere between a settings problem and the fact that the Growatt SPF5000 ES is ultimately an off-grid inverter, which has consequences.

I have come to suspect the fans (and probably the control circuitry) run off the 48V circuitry. When the inverter is operating in bypass mode because of inadequate PV power, the fans seem to run down the battery. With charging in float mode, this results in the charge and discharge cycle you describe.

Ultimately I have found this inverter works best with PV power installed when your priority setting is Solar, Battery, Utility (SBU mode).
There are settings so that you switch to utility "early" so that you have some reserve for loss of utility power (loadshedding), but all of this relies on having a battery setup that is intended for an off-grid environment with Utility as a fall-back option when PV and battery together isn't enough.

When used as a UPS or backup supply without PV, the priority setting should be UBS and the batteries will cycle across the float voltage setting range due to the internal load (fans in particular) on the 48V side - and the charge to Batteries from Utility into the 48V side being effectively intermittent.

Unfortunately I have no experience with firmware updates - so can't help you there. My only suggestion is make sure the load is disconnected when booting up the inverter in case what you are experiencing is an overload signal tripping problem (that is trying to protect the batteries from an overload). (Kinda a long shot - I am sure you have covered this possibility already).

[CJSOLAR]

Hi Dave A.
Thank you for the feedback.
Yes indeed I tried everything and basically I found no Change when adjusting the settings either SBU mode ect....
Like I said I did install both 2x same Growatt's with exactly the same amount kw PV and 48V batteries and only one gave me this problem of using the batteries and utility rather then PV first and then utility. I test the SBU but dont want to discharge the battries every full charge due to shorten the life span of them.

I also read that most people with this problem is using china technical support, I will give them a try....

I did do the firmware with batteries at first but after the first update file finished the inverter did not allowed me to do the second bin file because the inverter goes off on only batteries after about 5 seconds. I have to switch on and off then inverter start for a few second"s and goes off again, not allowing the update to finish.

I was brave to do the firmware thing Dave A, but so we learn every day something new.

Thank you for the feedback

[Dave A]

Like I said I did install both 2x same Growatt's with exactly the same amount kw PV and 48V batteries and only one gave me this problem of using the batteries and utility rather then PV first and then utility.

Fair enough. But did they have the same PV power production and load profiles once installed.

Anyhow, food for thought for another day. I hope you come right with the firmware setup. Please post how you resolved the problem once you get to the solution. It may help someone else one day...