Reset Full Charge Capacity on SOK 48V Batteries

Hi All,

I have been having some issues using a pair of 48V 5kwh SOK batteries with my Growatt 5000es. The batteries were not balanced and so I removed all coms and ran the system with manual setting values for a few weeks. Things appear to have improved but I still have some issues.

When the batteries were not balanced, one of them dropped from 107ah FCC to 91ah FCC. The first time i charged the batteries using manual settings, the battery charged past the 91 FCC all the way to 110ah. However this has never happened again and FCC has not reset to a larger value. I recall someone on this forum saying it could be reset.

Does anyone know how to get the battery to reset it to a better value?

Not sure what SOK batteries you have.
Download the SOK Tools software from:
or

With this software you can view individual cell voltages for each battery

Yes this is the battery I have (two of them).

My question is, when will they reset their FCC? I’m pretty sure the new one with 15 cycles hasn’t really gone from 107ah to 91ah. As I said, the first time I charged using manual settings it charged to 110ah on the battery display but since then it stubbornly stays at 91ah current and max even though it continues to charge for several more hours at 1-2kw.

If you get the cells to charge to 3.45 vdc the BMS will start balancing and the BMS will rest the SOC to 100%

You will need a serial to USB cable, this is the one I use.

You can start charging with the inverter bulk and float set to 56.5vdc. Once the cells (or some of the cells) start approaching 3.45 reduce the charge voltage at the inverter to around 55.5 to slowly complete the charge. As each cell reaches 3.45 you will see a BL in blue appear after the box displaying the cell voltage and you will see the SOC reset to 100%

How do I do things like ‘reduce the charge’?

All I can do is let the solar charge the battery until it stops charging right?

I suspect you have to set menu item #5 to User-Defined or User-defined-2 (page 15 of the manual) then you can set #19 and #20


Search:
manually set Growatt 5000es SOK Batteries

Yes I have set all these settings and I believe the batteries are now balanced. They certainly dont seem to be massively out of sync now.

However my question remains: when/how will the SOK battery reset its FCC value?

Y2JB said:

Yes I have set all these settings and I believe the batteries are now balanced. They certainly dont seem to be massively out of sync now.

However my question remains: when/how will the SOK battery reset its FCC value?

Click to expand...

I don't have a FCC notation on my SOK Tools program. Are you talking about the Full Capacity box under pack information? If so, I ran into similar issues where the Full Capacity and SOH (State of Health) were wildly out of sync. Current Connected recommended to drain the batteries fully down, then recharge fully to reset the batteries. That worked for me.

MiSh said:

I don't have a FCC notation on my SOK Tools program. Are you talking about the Full Capacity box under pack information? If so, I ran into similar issues where the Full Capacity and SOH (State of Health) were wildly out of sync. Current Connected recommended to drain the batteries fully down, then recharge fully to reset the batteries. That worked for me.

Click to expand...

I’m referring to the FCC value displayed on the little screen on the unit under the analogue info -> cell capacity menu.

All-in-one 12v LFP batteries without an internal BT monitor leaves you running blind on the internal four cells voltage balance.

Since BMS's do not balance dump until a cell reaches 3.4v you have to periodically do an absorb level charging to get some balancing time. Many self-contained 12 v LFP have a feebly low resistor dump balancing bleed current in 100 mA range so they can take a long time to balance out.

A sure sign cells are significantly out of balance is if you get a BMS charge shutdown due to a cell overvoltage when attempting a full charge with a charge absorb voltage set to 14.4vdc. When this happens, it can take ten's of hours held at 14.2v absorb voltage to achieve enough balance dump time to get cells back in balance.

There may be several charge shutdown periods along the way to full rebalancing. Some chargers will see the BMS charge shutdown as battery has completed charging and drop to a lower float voltage which means there will likely be no further balancing.

Y2JB said:

I’m referring to the FCC value displayed on the little screen on the unit under the analogue info -> cell capacity menu.

Click to expand...

Yes, that's the same value as Full Capacity shown on the SOK tools program. I totally discharged my batteries, then fully charged and everything reset back to the original values.

You mean charge all the way until the bms low voltage disconnect kicks in?

Thanks for the advice!

MiSh said:

Yes, that's the same value as Full Capacity shown on the SOK tools program. I totally discharged my batteries, then fully charged and everything reset back to the original values.

Click to expand...

You mean charge all the way until the bms low voltage disconnect kicks in?

Thanks for the advice!

marionw said:

If you get the cells to charge to 3.45 vdc the BMS will start balancing and the BMS will rest the SOC to 100%

You will need a serial to USB cable, this is the one I use.

https://www.amazon.com/dp/B09P8D5WL9?psc=1&ref=ppx_yo2ov_dt_b_product_details

You can start charging with the inverter bulk and float set to 56.5vdc. Once the cells (or some of the cells) start approaching 3.45 reduce the charge voltage at the inverter to around 55.5 to slowly complete the charge. As each cell reaches 3.45 you will see a BL in blue appear after the box displaying the cell voltage and you will see the SOC reset to 100%

View attachment 203283View attachment 203284

Click to expand...

How did you get the threshold to 3.45? Mines says 3.5. I am not able to change it.