Sungoldpower stuck in UVP

[TheGreatHurlyBurly]

My SG48100m battery is stuck in UVP mode. It's been cold here for the last several days so I had the battery and inverter powered down. SOC was ~50% when I shut it all off. Its well above freezing today and when I turned the system back on the inverter gave me an error 71(battery not allowed to discharge). I checked the battery and it seems to be stuck in UVP mode and wont allow charging or discharging. Voltage is 49.7v though so it shouldn't be in UVP mode as far as I can tell. I tried resetting the battery but it's still in UVP mode. Anyone seen this before?

 

[42OhmsPA]

Are you using battery communications?
If so I'd disconnect them, set to user and attempt to charge. Do you have grid or a generator?

 

[TheGreatHurlyBurly]

Are you using battery communications?
If so I'd disconnect them, set to user and attempt to charge. Do you have grid or a generator?

I tried resetting the battery with and without the comm cable. I have a generator but it's a small one and the inverter never liked it. Too much THD. I have a Chargeverter ordered but they're on back order.

 

[42OhmsPA]

Hmmm I'm out of ideas.
Good luck.

 

[Crowz]

Just because its above freezing there now doesn't mean the battery is above freezing temp wise.

What does the battery say the temperature is at?

 

[TheGreatHurlyBurly]

Just because its above freezing there now doesn't mean the battery is above freezing temp wise.

What does the battery say the temperature is at?

Battery says it's at 7.2C or roughly 45°F

 

[Crowz]

Does it have a reboot option or a clear errors choice? Once it gets to cold and sets the error it probably requires user intervention to get it going again.

 

[TheGreatHurlyBurly]

Does it have a reboot option or a clear errors choice? Once it gets to cold and sets the error it probably requires user intervention to get it going again.

Last time it did this I had left it on overnight and it discharged way past where it is now. I just reset it and it came back up. This time the battery reset doesnt seem to do anything.

 

[TheGreatHurlyBurly]

So if I'm reading this right, the over discharge protection should only cut off at 40v then releases at 44.8v

 

[TheGreatHurlyBurly]

So sungold reached out to me. Their "fix" was to simply charge the battery. That's well and good but it didnt really explain why a 48v battery at 49.7v would be considered low voltage enough to not discharge.

 

[Crowz]

Well since 48v is 9% and 50v is 14% state of charge that will put 49.7 around 10% state of charge which is considered the absolute lowest you want to go by most manufacturers. So it sounds like its working as designed so yes you need to charge the battery.

 

[Crowz]

Also its not a 48v battery its a 51.2v battery. Calling it a 48v is perfectly fine when talking about these batteries in general but when deciding if its dead or not the 51.2v part is important.

 

[TheGreatHurlyBurly]

Also its not a 48v battery its a 51.2v battery. Calling it a 48v is perfectly fine when talking about these batteries in general but when deciding if its dead or not the 51.2v part is important.

Yes I understand its 51.2v, 48v is the common term for it. However, in their documentation it states the battery has a low voltage disconnect at 40v and a release of that disconnect once its back up past 44.8v so one would think 49v would work, yeah? When I put the battery and inverter in storage it was reading 50% SOC, so is the SOC its reading wrong? The WatchPower app for the inverter doesnt display the correct SOC either, it's always off by 5% - 10%. I thought that's close enough, but maybe none of them are reading the right SOC, battery, app, or inverter.

I get that it needs to be charged but that doesnt help me understand why its not working and how to prevent it in the future. I stored the battery per their specifications, SOC between 40% and 60%, when I shut down for the cold weather. I'm just trying to understand what went wrong. Thanks for your time.

 

[Crowz]

Yes I understand its 51.2v, 48v is the common term for it. However, in their documentation it states the battery has a low voltage disconnect at 40v and a release of that disconnect once its back up past 44.8v so one would think 49v would work, yeah? When I put the battery and inverter in storage it was reading 50% SOC, so is the SOC its reading wrong? The WatchPower app for the inverter doesnt display the correct SOC either, it's always off by 5% - 10%. I thought that's close enough, but maybe none of them are reading the right SOC, battery, app, or inverter.

I get that it needs to be charged but that doesnt help me understand why its not working and how to prevent it in the future. I stored the battery per their specifications, SOC between 40% and 60%, when I shut down for the cold weather. I'm just trying to understand what went wrong. Thanks for your time.

Between all Ive seen people going thru lately trying to use the bms on the battery to run things in closed loop aka with coms hooked up I wouldn't trust anything they showed soc wise.

I would use a victron smart shunt with solar assistant to know what was really going on it it was me.

40v is slap dead. That's not a usable inverter setup cutoff voltage. That's a lets see if we can kill the battery point.

52.5v is 50% soc.

 

[Lt.Dan]

It might be UVP for a single cell. There very well could be 1 cell at 2.5v, and the rest at 3.0v, making up the higher total voltage you see.