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SOK SK48V100 Batteries Dead - How to restart?

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ccpeabody

New Member
Joined
Jun 12, 2022
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29
Hi Folks,

I have two LV6548 Inverters running our off grid cabin along with 5 SOK SK48V100 Server rack batteries and a host of solar panels.

I just stopped down today to bring some supplies for the construction crew and see that they left their air compressor running all weekend and have completely killed all the batteries. Ie. SOC = Zero.

I figured, no worries, I’ll just start the generator and charge them back up. No dice. Inverters are giving the BP error code (Battery Disconnected) and the battery bank is not charging.

I’m guessing the BMS on the batteries had disconnected them? Is there a way to fire this system back up or do I need to find a 48V Charger somewhere and charge the batteries individually first before putting them back in the system.

At the cabin now scouring the net if anyone decicdes to chime in.

Cheers!
 
First of all, this shouldn't have happened.
Your inverters should have shut down way before the BMS did.
Please check the settings on the inverters, to make sure that the low voltage cutoff is above the BMS's low voltage disconnect.

I think that by giving a small 48v charge, the BMS should get back to work. But, since the BMS disconnected from the inverters, you might have some high inrush current if the capacitors on the inverters have already depleted/discharged, which might cause the BMS to go into short circuit protection.

I would turn off the inverters and disconnect them from the batteries. I hope you have a disconnect switch or breaker of some sort.

Then give the battery bank a short 48v charge (maybe a bit higher, like 52v). Then reconnect the battery bank to the inverters, but make sure to use a pre-charge resistor.

Now the battery bank should accept charge via the inverters.
 
I'm not a user of SOK batteries so not sure if the BMS needs to be reset via some procedure or if a source of 48V would be enough to start the charging cycle. What does the SOK manual have to offer about the subject? Regarding the 48V charger, I believe its worth a try and would suggest using something inexpensive that simply supplies 48V regardless of whether it senses battery voltage or not. Something like this that could be connected to your car battery or even a 12V automotive charger. https://www.ebay.com/itm/3935081375...sa-KjRdL6tf0JDUFCSg4o0UGROfud55xoCDPAQAvD_BwE

48V will not fully charge the battery but it will get the cells above the cut out limit which is usually about 2.5V and maybe help you determine if the batteries are OK.

The bigger issue here is how did this happen? Are the inverters set to shut down before the batteries are completely dead? If so, why didn't the "host" of solar panels recharge it the next day? With 5 batteries its hard to believe the standby load could have drained the batteries overnight if the inverters shut down properly on Low Batt voltage.
 
ccpeabody said:
Hi Folks,

I have two LV6548 Inverters running our off grid cabin along with 5 SOK SK48V100 Server rack batteries and a host of solar panels.

I just stopped down today to bring some supplies for the construction crew and see that they left their air compressor running all weekend and have completely killed all the batteries. Ie. SOC = Zero.

I figured, no worries, I’ll just start the generator and charge them back up. No dice. Inverters are giving the BP error code (Battery Disconnected) and the battery bank is not charging.

I’m guessing the BMS on the batteries had disconnected them? Is there a way to fire this system back up or do I need to find a 48V Charger somewhere and charge the batteries individually first before putting them back in the system.

At the cabin now scouring the net if anyone decicdes to chime in.

Cheers!
Click to expand...
Yes.
First turn the batteries off.
2nd hold down the RST button with pen or aomething for 3 seconds. The battery should reset, look for the blinking lights.

I have a related problem right now myself. Everything is turning off after the batteries "died". The batteries take a charge for ~12 minutes then the charge controller shuts everything down to ~30watts and the inverter turns off the house feed.

I feel like it is on a timer almost.
 
meetyg said:
First of all, this shouldn't have happened.
Your inverters should have shut down way before the BMS did.
Please check the settings on the inverters, to make sure that the low voltage cutoff is above the BMS's low voltage disconnect.

I think that by giving a small 48v charge, the BMS should get back to work. But, since the BMS disconnected from the inverters, you might have some high inrush current if the capacitors on the inverters have already depleted/discharged, which might cause the BMS to go into short circuit protection.

I would turn off the inverters and disconnect them from the batteries. I hope you have a disconnect switch or breaker of some sort.

Then give the battery bank a short 48v charge (maybe a bit higher, like 52v). Then reconnect the battery bank to the inverters, but make sure to use a pre-charge resistor.

Now the battery bank should accept charge via the inverters.
Click to expand...
Thank you for taking the time to reply.

After a little reading, I figured that I must have something programmed incorrectly in the inverters. I just used a recommended settings post from somewhere using the same set up. The problem with that is, instead of educating myself on the correct settings, it looks like I helped create the failure. The communication software on the LV6548's doesn't work with the SOK batteries without sticking your interface in the freezer and attempting to send some internet firmware upgrade to the unit. I wasn't willing to go that route. I'm not sure the inverters will sense the voltage on the batteries without the communication cable but I would think it should. Again, more reading on my part.

No worries with the inrush current. The batteries have a smart start circuit.

Yes, I did design my system with a giant battery disconnect switch.

Now, it looks like I'll need to buy a 48V charger. Any chance you could suggest one? You seem to have your act together. It will have to be an Amazon purchase as I'm sure not a sole in my area will even know a 48VDC charger exists :)

Thanks again for taking the time to reply. I really appreciate it.
 
BentleyJ said:
I'm not a user of SOK batteries so not sure if the BMS needs to be reset via some procedure or if a source of 48V would be enough to start the charging cycle. What does the SOK manual have to offer about the subject? Regarding the 48V charger, I believe its worth a try and would suggest using something inexpensive that simply supplies 48V regardless of whether it senses battery voltage or not. Something like this that could be connected to your car battery or even a 12V automotive charger. https://www.ebay.com/itm/393508137577?chn=ps&_trkparms=ispr=1&amdata=enc:12we9XKzZSXCeX53DHr12xA82&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=393508137577&targetid=&device=c&mktype=pla&googleloc=9031520&poi=&campaignid=17597089569&mkgroupid=&rlsatarget=&abcId=9300988&merchantid=263030878&gclid=CjwKCAjwzNOaBhAcEiwAD7Tb6MSBm8spLttgNpwOYj3GRFsa-KjRdL6tf0JDUFCSg4o0UGROfud55xoCDPAQAvD_BwE

48V will not fully charge the battery but it will get the cells above the cut out limit which is usually about 2.5V and maybe help you determine if the batteries are OK.

The bigger issue here is how did this happen? Are the inverters set to shut down before the batteries are completely dead? If so, why didn't the "host" of solar panels recharge it the next day? With 5 batteries its hard to believe the standby load could have drained the batteries overnight if the inverters shut down properly on Low Batt voltage.
Click to expand...
Great post... Thank you.

SOK manual is yet to be completed. Unfortunately, the troubleshooting section is missing. I'll do some reading tonight and try to sort through when the BMS shuts down the batteries. As a side note, the batteries were all on when I arrived, but their state of charge was zero and the inverters were reporting BP which means a disconnected battery.

The batteries are at 43.3 volts.

How did this happen... I must have the low voltage cut out set incorrectly on the inverters. Either that, or because they don't communicate with the batteries, they don't know the state of charge of the batteries?

The compressor the carpenters left leaks constantly and is very large. The batteries lasted from Friday at noon until Sunday night at 5:00pm. That's pretty good considering the lack of sun we received here this weekend.

I'll have to order a 48VDC charger and wait for it to arrive. I don't think a 12VDC charger is going to be able to bump up a 48V battery with 43V capacity.

Again, thank you very much for taking the time to reply.
 
ccpeabody said:
Thank you for taking the time to reply.

After a little reading, I figured that I must have something programmed incorrectly in the inverters. I just used a recommended settings post from somewhere using the same set up. The problem with that is, instead of educating myself on the correct settings, it looks like I helped create the failure. The communication software on the LV6548's doesn't work with the SOK batteries without sticking your interface in the freezer and attempting to send some internet firmware upgrade to the unit. I wasn't willing to go that route. I'm not sure the inverters will sense the voltage on the batteries without the communication cable but I would think it should. Again, more reading on my part.

No worries with the inrush current. The batteries have a smart start circuit.

Yes, I did design my system with a giant battery disconnect switch.

Now, it looks like I'll need to buy a 48V charger. Any chance you could suggest one? You seem to have your act together. It will have to be an Amazon purchase as I'm sure not a sole in my area will even know a 48VDC charger exists :)

Thanks again for taking the time to reply. I really appreciate it.
Click to expand...
This seems quit similar to my issues, can you follow up and let me know if your solution works
 
As meetyg stated, settings were incorrect.

From the SOK manual:

Standalone Operation Charge Setpoints​

  • Charge Current for normal use: Up to 63A (Per Battery)
  • Charge Current for fast charge: Up to 95A (Per Battery)
  • Absorption Voltage: 57.6v recommended; up to 58.4v max
  • Absorption Time: 15 Minutes
  • Float Voltage: 55.2v
  • Charging Target: 100% SOC
  • Low Voltage Shutdown: 48v
As can be seen, Low Voltage Shutdown should have been 48V. I had 43.2V set.

I ordered this unit from Amazon and it should be here Wednesday. Looks like a good sturdy unit and should be fairly useful with other systems as well.

https://www.amazon.ca/gp/product/B09QCTVCFF/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Thanks to everyone that took the time to respond.
 
ccpeabody said:
As meetyg stated, settings were incorrect.

From the SOK manual:

Standalone Operation Charge Setpoints​

  • Charge Current for normal use: Up to 63A (Per Battery)
  • Charge Current for fast charge: Up to 95A (Per Battery)
  • Absorption Voltage: 57.6v recommended; up to 58.4v max
  • Absorption Time: 15 Minutes
  • Float Voltage: 55.2v
  • Charging Target: 100% SOC
  • Low Voltage Shutdown: 48v
As can be seen, Low Voltage Shutdown should have been 48V. I had 43.2V set.

I ordered this unit from Amazon and it should be here Wednesday. Looks like a good sturdy unit and should be fairly useful with other systems as well.

https://www.amazon.ca/gp/product/B09QCTVCFF/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Thanks to everyone that took the time to respond.
Click to expand...
They have a 40A version for less.
 
You just need to reset the batteries.
The EG4 6500/LV6548 can run without batteries so why is it throwing an error ?
Get them both started and the inverter should charge the batteries.
 
TheBenjamin said:
Yes.
First turn the batteries off.
2nd hold down the RST button with pen or aomething for 3 seconds. The battery should reset, look for the blinking lights.

I have a related problem right now myself. Everything is turning off after the batteries "died". The batteries take a charge for ~12 minutes then the charge controller shuts everything down to ~30watts and the inverter turns off the house feed.

I feel like it is on a timer almost.
Click to expand...
Sounds very similar to how the eFlex batteries are designed for recovery from deep discharges. A semi dead eFlex will power on with one LED blinking.
You have 15 minutes to connect a charger and then when the voltage comes up high enough the BMS will turn on fully and take control of balancing the pack until it’s SOC is high enough that you can safely attach to the invert for the full charge.
 
ccpeabody said:
As meetyg stated, settings were incorrect.

From the SOK manual:

Standalone Operation Charge Setpoints​

  • Charge Current for normal use: Up to 63A (Per Battery)
  • Charge Current for fast charge: Up to 95A (Per Battery)
  • Absorption Voltage: 57.6v recommended; up to 58.4v max
  • Absorption Time: 15 Minutes
  • Float Voltage: 55.2v
  • Charging Target: 100% SOC
  • Low Voltage Shutdown: 48v
As can be seen, Low Voltage Shutdown should have been 48V. I had 43.2V set.

I ordered this unit from Amazon and it should be here Wednesday. Looks like a good sturdy unit and should be fairly useful with other systems as well.

https://www.amazon.ca/gp/product/B09QCTVCFF/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Thanks to everyone that took the time to respond.
Click to expand...
That looks like a handy charger. Something like that should be on the supply list for anyone doing this stuff. If I read that right all it cares about is getting to the preset voltage. So many chargers and inverters refuse to work when the BMS is in protection mode.
 
ccpeabody said:
How did this happen
Click to expand...
It does not get your problem fixed but it’s an example of a lesson learned for others, Always test any system after it is installed and setup. Your situation/problem would have been seen with testing and it’s always best to be present when something does not work properly and you can figure it out and fix it then.
 
robby said:
Sounds very similar to how the eFlex batteries are designed for recovery from deep discharges. A semi dead eFlex will power on with one LED blinking.
You have 15 minutes to connect a charger and then when the voltage comes up high enough the BMS will turn on fully and take control of balancing the pack until it’s SOC is high enough that you can safely attach to the invert for the full charge.
Click to expand...
Yes and there is a start up procedure as well to protect your capacitors
 
ccpeabody said:
As meetyg stated, settings were incorrect.

From the SOK manual:

Standalone Operation Charge Setpoints​

  • Charge Current for normal use: Up to 63A (Per Battery)
  • Charge Current for fast charge: Up to 95A (Per Battery)
  • Absorption Voltage: 57.6v recommended; up to 58.4v max
  • Absorption Time: 15 Minutes
  • Float Voltage: 55.2v
  • Charging Target: 100% SOC
  • Low Voltage Shutdown: 48v
As can be seen, Low Voltage Shutdown should have been 48V. I had 43.2V set.

I ordered this unit from Amazon and it should be here Wednesday. Looks like a good sturdy unit and should be fairly useful with other systems as well.

https://www.amazon.ca/gp/product/B09QCTVCFF/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Thanks to everyone that took the time to respond.
Click to expand...
Try changing your battery settings to USE on your controller
 
Quattrohead said:
You just need to reset the batteries.
The EG4 6500/LV6548 can run without batteries so why is it throwing an error ?
Get them both started and the inverter should charge the batteries.
Click to expand...
48VDC charger on the way to do just that.

Yes, the Inverters will work without the batteries but the issue is charging the batteries.
 
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