SOK 206ah charging to 15.6v?

[rvtyme]

I have a toyhauler with (3) 206ah SOK batteries wired in parallel for 618ah. I have a GoPower IC3000 inverter/charger and all has been working well. I configured the IC3000 with the following custom profile for this lithium setup.

Absorption: 14.4
Float: 13.5
Equalization: 14.4

This has been running well since Nov 2021.

Just recently I placed the trailer into storage with a 30amp connection. Only the security cameras and refrigerator (residential refrigerator) is drawing AC power with everything else off. Power went out at the storage facility for several days which depleted my batteries and caused the BMS (assuming) to cut off and the entire RV to be completely dead. AC power was restored but I had a hard time getting the IC3000 back online even when plugged in. I had an OVP error (over voltage protection) on the IC3000 that just would not clear. I was told by GoPower tech support that the IC3000 needs the battery voltage at a certain level for it to come back online - when I thought applying 30amps of house power to the IC3000 would be enough to trigger the battery charger to bring them back up - but they tell me that is not the case. I was able to get things going by starting the generator and running it for 15 mins or so... not sure if the IC3000 was just confused or what.. not a clue.

Well, the batteries were getting charged and everything looked normal - or so I thought. The batteries are now at 15.7v!! What is going on here? Did the low voltage dip cause an issue with the BMS or is my IC3000 have an issue? I felt all the wiring, nothing hot, felt the batteries - they are cool - why 15.7? Thoughts on how to troubleshoot this?

 

[chrisski]

IMO after using lithiums for a couple of month, 14.4 volts or 3.6 per cell is too close to the limit. I now charge with 3.475 per cell, or 13.9 volts.

So first I may try a lower charge voltage to see if it comes back. That would probably just work for a single cell over voltage.

I have spare SCCs, and would try charging the batteries through those to see if I get the same error.

 

[rvtyme]

IMO after using lithiums for a couple of month, 14.4 volts or 3.6 per cell is too close to the limit. I now charge with 3.475 per cell, or 13.9 volts.

So first I may try a lower charge voltage to see if it comes back. That would probably just work for a single cell over voltage.

I have spare SCCs, and would try charging the batteries through those to see if I get the same error.

Thanks for the response. What is super concerning is that my charge profile is for 14.4 yet my batteries are at 15.6 currently - isn't this telling me that the IC3000 isn't switching to float after hitting 14.4 as it is suppose to?

 

[John Frum]

The battery bms should be isolating the battery when the voltage exceed 14.6 volts or 3.65 volts per cell.
Did you disable your ac2dc converter when you installed the inverter/charger?
Do you have any other charge sources?

I suspect you either have another charge source that is trying to equalize your batteries.

 

[rvtyme]

The battery bms should be isolating the battery when the voltage exceed 14.6 volts or 3.65 volts per cell.
Did you disable your ac2dc converter when you installed the inverter/charger?
Do you have any other charge sources?

I suspect you either have another charge source that is trying to equalize your batteries.

Yes, the old converter was removed when the Inverter/charger was installed. I do have a solar charge controller but I am getting nothing off the panels since the trailer is covered under a roof protecting the RV from the sun. This isn't a new installation, this installation has been operational since Oct 21 and has been working fine until this power outage happened at the RV storage facility - which is why it is baffling to me. I just wonder if the charging circuitry may have just gone bonkers.... I just don't want to fry my batteries. I guess it is time for another trip to the RV to continue troubleshooting this.

 

[John Frum]

Yes, the old converter was removed when the Inverter/charger was installed. I do have a solar charge controller but I am getting nothing off the panels since the trailer is covered under a roof protecting the RV from the sun. This isn't a new installation, this installation has been operational since Oct 21 and has been working fine until this power outage happened at the RV storage facility - which is why it is baffling to me. I just wonder if the charging circuitry may have just gone bonkers.... I just don't want to fry my batteries. I guess it is time for another trip to the RV to continue troubleshooting this.

15.6 volts would be very hard on the battery.
I hope that the bms protected the battery by opening the fets in the charge path.