Growatt SPF6000T DVM warning code 04 even though battery voltage is not that low

[Philectric246]

Hi All

I think I am finally getting my Growatt SPF6000T DVM with 48V 15S Rosen battery to run half-decent but I have one issue that I find a little confusing. At night while I am on the battery and even after the inverter switches back to the grid I get warning code 04(Battery Voltage Low/Battery State of Charge Low) but when I look at the voltage on the inverter and I check the cells on the LCD of the battery, they don't seem that low.

It happened a few minutes ago and all the cells in the battery were around 3150mV, which I believe is a pretty decent voltage. The inverter has been doing this for a while now but it never shuts down. The state of charge on the LCD was saying 10% but I don't think that could be right if the average cell voltage is 3.15V. Please make it make sense.

Thanks

 

[sunshine_eggo]

Oh, it's low.

Yeah, 10% is not too far off. You're likely no higher than 15%, and it's likely driven by the lowest cell, not the average.

 

[Philectric246]

Oh, it's low.

Yeah, 10% is not too far off. You're likely no higher than 15%, and it's likely driven by the lowest cell, not the average.

Thanks for your reply. Do you have any suggestions? I am thinking raise the voltage that the inverter goes back to the grid at, I don't want to hurt the battery.

 

[sunshine_eggo]

It shouldn't hurt it, but if the error is annoying try raising it a little.

Is the error normal - simply in response to triggering the failover to grid?

 

[Philectric246]

Thanks, I raised it a bit and I will monitor it.

I don't think it's normal, flashing red lights and error codes make me wonder what's wrong.

Anyway, thanks to you guys on this Forum, the Growatt finally seems to be working ok. I need some more battery and probably some more panels to make it through the night.

This is what I'm working with
Growatt SPF6000T-DVM 150V + Rosen 48 200AH 15S battery, 9 x 480w panels
01 SBU
02 80
03 APL
05 USE
06 Disabled
08 240V
09 50Hz (that's what we use here, not a mistake)
11 30A
12 47.4V Back to grid
13 50.0V Back to battery
14 OSO Only solar charging
15 bON
16 lON
17 AON
19 53.4V Cv Bulk
20 53.4Cv Float
21 45.6 battery cut off voltage

 

[Brett V]

Having your Bulk and Float voltages the same has been known to cause problems.

Edit: I deleted my comment on recommended voltages, unsure if your battery is LFP or LIO.

 

[sunshine_eggo]

Having your Bulk and Float voltages the same has been known to cause problems.
Also, I would say your voltages are too low. Raise Bulk in setting 19 to 55.2 nd raise Float in setting 20 to 54.0

I didn't notice that... Agreed - problematic.

It's a 15S battery, so your voltages are too high, but 3.45V/cell for bulk and 3.375V/cell for float are spot on.

 

[Brett V]

I didn't notice that... Agreed - problematic.

It's a 15S battery, so your voltages are too high, but 3.45V/cell for bulk and 3.375V/cell for float are spot on.

I did a google search on his battery model after I posted and realised it might not be LFP. Corrected post.

 

[sunshine_eggo]

I did a google search on his battery model after I posted and realised it might not be LFP. Corrected post.

EW! 15S is very uncommon for 3.7V chemistry, so I assumed LFP and 15S LFP is truly 48V nominal, though less optimal for 48V systems running lead acid.

@Philectric246 Please provide your battery specifications.

 

[Philectric246]

I didn't notice that... Agreed - problematic.

It's a 15S battery, so your voltages are too high, but 3.45V/cell for bulk and 3.375V/cell for float are spot on.

Having your Bulk and Float voltages the same has been known to cause problems.

Edit: I deleted my comment on recommended voltages, unsure if your battery is LFP or LIO.

It's a LifeP04 battery, I raised the voltages a couple days ago to see if I could get the battery to charge some more but so far I haven't seen any increase in overall charge. Maybe because it's switching back to battery as soon as it reaches 50V. I have set bulk to 51.8V and float to 50.6. It was still beeping tonight so I raised the back to grid voltage to 47.7V. When I checked the battery, the state of charge was 9.65%, the lowest cell was around 3170 and 3180mV.

i have heard conflicting information about floating LifeP04 batteries, some say that you don't need to float them and others say that a slightly lower float voltage will charge the batteries more.

Electrical Parameters for the battery
Operation voltage 48Vdc
Max. charging voltage 54.75DC
Cut-off discharge voltage 40.5Vdc
Max. discharging current 150Adc
Max. charging current 100Adc

Having your Bulk and Float voltages the same has been known to cause problems.

Edit: I deleted my comment on recommended voltages, unsure if your battery is LF

 

[Philectric246]

I did a google search on his battery model after I posted and realised it might not be LFP. Corrected post.

Thanks for your input, I put the battery specs in the thread.

 

[sunshine_eggo]

It's a LifeP04 battery, I raised the voltages a couple days ago to see if I could get the battery to charge some more but so far I haven't seen any increase in overall charge. Maybe because it's switching back to battery as soon as it reaches 50V. I have set bulk to 51.8V and float to 50.6. It was still beeping tonight so I raised the back to grid voltage to 47.7V. When I checked the battery, the state of charge was 9.65%, the lowest cell was around 3170 and 3180mV.

i have heard conflicting information about floating LifeP04 batteries, some say that you don't need to float them and others say that a slightly lower float voltage will charge the batteries more.

Electrical Parameters for the battery
Operation voltage 48Vdc
Max. charging voltage 54.75DC
Cut-off discharge voltage 40.5Vdc
Max. discharging current 150Adc
Max. charging current 100Adc

Given the above, the following applies.

I didn't notice that... Agreed - problematic.

It's a 15S battery, so your voltages are too high, but 3.45V/cell for bulk and 3.375V/cell for float are spot on.

 

[Philectric246]

Thanks, I have adjusted the bulk and float as suggested. Time will tell