The right inverter for battery storage and some other Qs

[ducabi]

What parameters should I set for my 3 US3000C batteries in sofar inverter?
At the moment i have:
DD 85%
Max charge 65A
Over protection 54.2V
Max charge 63.2V
Max discharge 65A
Min discharge 47v.

I've looked at manual for batteries but am a bit confused what different ranges mean.

[Oldgreybeard]

They shouldn't need any voltage settings if the data cable is connected and working, as the inverter will be controlled by the battery BMS. A max charge voltage of 63.2V is way too high, highest I've ever seen on our stack of US3000Cs is around 52.5V and the absolute maximum safe voltage is about 54.75V (pretty sure the Pylontech BMS shuts down well before this voltage).

There should be a setting in the inverter to select the battery type, and if this is set to Pylontech it will override most of the individual charge and discharge settings, with the exception of maximum charge current. This is limited by the inverter capability anyway, and for our ME3000SP it's around 60A I think, for your inverter 65A sounds about right.

[nowty]

The fact that the over protection is 54.2V, I presume its a typo and he means 53.2V instead of 63.2V, otherwise its,

[ducabi]

Yup, typo, 53.2v. On the screen i can see set parameters and BMS parameters and they are the same for amperage but there are no info about voltage from BMS does it mean it will run based on what i set? I would prefer BMS looking after everything .

What SOC do you use for daily use? I have DD 85% SOC 90% and can see that the battery charged 7kWH last night (of 10.5kWh). I'm 1kWh short in the evenings and wonder which parameter I can change but on the other hand I think the above settings should give me around 8kWh. Unless the batteries are still doing some balancing.

[Oldgreybeard]

Yup, typo, 53.2v. On the screen i can see set parameters and BMS parameters and they are the same for amperage but there are no info about voltage from BMS does it mean it will run based on what i set? I would prefer BMS looking after everything .

Glad that was a typo! If the inverter battery type is set to "Pylontech" in the menu and the data cable is properly connected, then the BMS will control the inverter voltage settings, with no need for any user input.

What SOC do you use for daily use? I have DD 85% SOC 90% and can see that the battery charged 7kWH last night (of 10.5kWh). I'm 1kWh short in the evenings and wonder which parameter I can change but on the other hand I think the above settings should give me around 8kWh. Unless the batteries are still doing some balancing.

Depends on your usage. I have six US3000C packs, and we use around 6kWh to 10kWh per day from the battery. I leave the inverter set to Time of Use mode most of the time, the exception being when we get a prolonged sunny spell, when I'll manually switch it to auto, so we don't even use off-peak electricity overnight, but run solely on PV. In ToU mode I set the SoC to 55% in summer, as that gives us enough headroom to put about 9.5kWh in from the PV the following day, and also gives us around 8.4kWh of usable energy to tide us through a dull day.

In winter I change the SoC to 75%, as we will rarely get a sunny enough winter day to get to 100% charge from that SoC, and having the 12.6kWh available for a dull day is pretty much essential to make sure we don't end up using peak rate electricity. I should add that although I have the newer batteries that can be discharged to 5%, I haven't updated the firmware in the inverter, so it will only allow the packs to discharge to 15%.

[ducabi]

My Discharge depth is set to 80% and I can't change it higher than 85% why? Is it just a matter of updating inverters software?
2nd question, inverter switched to grid with SOC 29%? How does it relate to 80% DD?

[Oldgreybeard]

My Discharge depth is set to 80% and I can't change it higher than 85% why? Is it just a matter of updating inverters software?
2nd question, inverter switched to grid with SOC 29%? How does it relate to 80% DD?

The Sofar inverter limits the minimum discharge when set to Pylontech mode to 15% SoC (hence the 85% DoD). They haven't yet caught up with the change Pylontech made a couple of years ago that allows discharge to 5% SoC, AFAIK. I heard a rumour a year or so ago that there was new Sofar firmware to allow going down to 5%, but I've not really investigated it, as 15% as a lower limit isn't an issue for us 99% of the time.

Not sure why the inverter switched to the grid at 29% SoC, our ME3000SP doesn't do this until the batteries hit 15% SoC. It may possibly be that the Pylontech batteries haven't settled in yet, perhaps. I found that it took a few days for the second set of three I added to the three I fitted a couple of weeks earlier to get themselves balanced and sorted out. Pylontech cell balancing seems to be a fairly slow process from what I can see, so perhaps give your system a bit longer to settle and see if it then goes down to 15% (the BMS can tell the inverter to stop discharging if any cell in any of the batteries hits the low voltage cut off point).

[Tinbum]

Sofar do have firmware to allow 90% DOD. They won't release one for 95%. They also now do firmware for the US5000 batteries as well. Its all available on line if you search.

[Oldgreybeard]

Sofar do have firmware to allow 90% DOD. They won't release one for 95%. They also now do firmware for the US5000 batteries as well. Its all available on line if you search.

Thanks, that's good to know. Not sure if I'll bother to change the firmware though, as what we have seems to work OK and I might well bugger something up if I start fiddling with it!

[ducabi]

1-2 lighrs, 4rd socket, 4th from the left is inverter, 5th is SPD.
1) Is it just the inverter that need to be upgraded to RCBO?
2) couldn't find tool to measure the cable but by the look of others what size could it be?
3) anything worrying here?