Sunsynk with pylontech batteries DC voltlow fault

[Cuzz]

Morning

We have been without grid power the last 2 days. This morning I woke to my sunsynk 8.8kw inverter sounding an alarm f56 DC voltlow fault. My state of charge is 19%. Will this error clear itself once the system charges the battery enough? Or do I need to manually clear the fault. Also if I am getting this error is there a battery configuration that I must change to avoid it discharging to this extent? I have 2 pylontech Us3000 batteries. 

[Achmat]

1 hour ago, Cuzz said:

Morning

We have been without grid power the last 2 days. This morning I woke to my sunsynk 8.8kw inverter sounding an alarm f56 DC voltlow fault. My state of charge is 19%. Will this error clear itself once the system charges the battery enough? Or do I need to manually clear the fault. Also if I am getting this error is there a battery configuration that I must change to avoid it discharging to this extent? I have 2 pylontech Us3000 batteries. 

The fault codes do not clear at its a history of the fault codes. 

You have too little batteries for the 8kw sunsynk inverter. What happened was that the BMS limits the discharge to 37A per battery. That equates to 3.4kw for two batteries. Your load must have gone higher than this for the inverter to give that error. I've had it a couple of times in my 8kw with 3 us3000 batteries. I now have 4 pushing the max discharge to 6.8kw. 5 x US3000 batteries is ideal. 

It's not the SOC that caused the error but the amount of power that was drying drawn from the batteries. 

[YellowTapemeasure]

1 hour ago, Cuzz said:

Morning

We have been without grid power the last 2 days. This morning I woke to my sunsynk 8.8kw inverter sounding an alarm f56 DC voltlow fault. My state of charge is 19%. Will this error clear itself once the system charges the battery enough? Or do I need to manually clear the fault. Also if I am getting this error is there a battery configuration that I must change to avoid it discharging to this extent? I have 2 pylontech Us3000 batteries. 

You can set the battery discharge rate on the inverter in the battery screen (max 74A for two US3000s), and the DoD of the battery in the system mode screen.

[Cuzz]

Thank you Achmat and Yellowtapemeasure. I will save up for the extra batteries. In the meantime I allowed the batteries to charge up and then restarted the inverter and the alarm sound stopped. I can still see the code in the history which is fine.

Is there a formula to calculate how many batteries one needs? 

 

[Tariq]

You would have to reset the inverter to get rid of the fault codes, but it does not hurt anything being there.

[Achmat]

16 minutes ago, Cuzz said:

Thank you Achmat and Yellowtapemeasure. I will save up for the extra batteries. In the meantime I allowed the batteries to charge up and then restarted the inverter and the alarm sound stopped. I can still see the code in the history which is fine.

Is there a formula to calculate how many batteries one needs? 

 

Discharge rate of the battery would determine the minimum number of batteries. Pylontech if rated at 0.5C so you will need 16kw of pylontech batteries to the 8kw sunsynk. Hubble is 1C so you only need 8kw of hubble batteries. 

It does not mean that the inverter cannot run with less batteries.