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New SOK 100ah Cells Out of Balance

In your case I would do the following:
Stop all charging, and use the batteries untill you get to a low voltage (below 3v per cell).
Then charge the batteries separately with a decent amperage up to about 80-90% SOC (3.4v per cell). Then charge them SLOWLY (still separately, say no more than 1A), up to 100%. This slower charging at the top should allow the balance current to keep up with the charge current. I'm not sure what the balance current on the SOK is, but maybe you will need to go even lower on the charge current.
You state : "Then charge them SLOWLY (still separately, say no more than 1A), up to 100%."
Then you state: "This slower charging at the top should allow the balance current to keep up with the charge current."
If you are charging the batteries (do you mean cells) separately, how is it even possible to have a balance current.
I must be misunderstanding what you say ?
 
I think what Meetyg means by "balance current", is the amount of current that the BMS is able to draw from the battery/charger combination to keep its voltage down. The BMS will use a certain resistor value to draw down each battery but can only draw so much due to the size and resistance of that passive balancing resistor.

By keeping the maximum charge current down, the BMS should be able to keep up with that low-ish current
 
You state : "Then charge them SLOWLY (still separately, say no more than 1A), up to 100%."
Then you state: "This slower charging at the top should allow the balance current to keep up with the charge current."
If you are charging the batteries (do you mean cells) separately, how is it even possible to have a balance current.
I must be misunderstanding what you say ?
Sorry for my wording...
I didn't mean the cells, I meant the 12v battery packs. You stated you have two of them. So I meant to charge them each separately.
 
This is getting to be stupid, OK you all act like if he put an active balancer he is going to be put on FBI most wanted list.

CHILL OUT.

OP buy an active balancer and try it out, then do a few charges and see if you like it or not.

If not at most you have spent 25.

BIG whoop.


Like For real this forum some times....
 
I'm seeing something similar with my SOK 100ah battery. I have a Victron Blue Smart IP65 15a charger. I'm using the posted LiFePO4 settings on the Current Connected page:

Absorption Voltage: 14.6v
Float Voltage: 13.8v
Storage Voltage: 13.6v
Recondition Voltage: Disabled
BatterySafe: Disabled

The charge gets "Interrupted" and then shows "Completed". When looking at the battery, the "C MOS" kicked on and stopped the charge. I disconnected the battery when it reached 'float' mode.

Looking at the details of the battery, the highest cell is 3.352v and lowest is 3.312v and a diff of .04v. After I put a load on the battery, it jumps down to 3.327v and 3.325v with a diff of .002v.

This is my first experience with batteries and charging, so I have no clue what I'm doing. I don't feel comfortable with opening the box and fiddling around with the insides. My gut is telling me that my absorption voltage may be set a bit too high, causing the battery to stop accepting a charge, and showing the interrupted state on the charger, which doesn't balance the cells.

Am I on the right path with this, or is there a bigger issue?
 
Well, I tried the parameters and the charge now says 'completed' instead of interrupted....which is a good sign. Unfortunately though, it looks like the cells may still be out of balance, which was what the OP was talking about.

HV: 3.706v
LV: 3.38v
DV: .326v

Is this something I should be concerned about? Keep an eye on it? Adjust another setting?
 
Did no one notice the cycle count here is zero?
FireShot Capture 168 - New SOK 100ah Cells Out of Balance - DIY Solar Power Forum_ - diysolarf...png

Try cycling it 20 times and leaving it at high soc and give it a month. This is very common on new batteries. It takes a few weeks for a passive dissipative balancer to do its job.

Don't use an active balancer, those are a waste of money. Let the BMS balancing circuit work it out.

I think people should stop checking their cell voltages. Do a capacity test and see what it pulls. If it does not pull full capacity, return it.
 
Put an active balancer and be done. I don't know why they have such a bad rep, both Will and Andy seem to hate them but I never had an issue. I have made 2-3 batteries with rando cells and it brings them all up to 3.63v.

Its the one with the red capacitors and sells for like 25 bux on aliexpress.
Yes, because it is a waste of money, unnecessary and increased chance of something going bad. They can fail for absolutely zero reason (most are cheaply made and I have fried 3 so far), and every non-fused conductor leaving a raw cell terminal is a liability. And so is another board, especially when it is unnecessary.

The BMS has a balancer. There is absolutely zero utility to using an active balancer. Top balance and do a capacity test and that will be the best capacity you can get.

In this case, this person never cycled the battery. So of course there will be some deviation in cell voltages. They need to use the battery and cycle it hard, so it can balance.
 
I'm seeing something similar with my SOK 100ah battery. I have a Victron Blue Smart IP65 15a charger. I'm using the posted LiFePO4 settings on the Current Connected page:

Absorption Voltage: 14.6v
Float Voltage: 13.8v
Storage Voltage: 13.6v
Recondition Voltage: Disabled
BatterySafe: Disabled

The charge gets "Interrupted" and then shows "Completed". When looking at the battery, the "C MOS" kicked on and stopped the charge. I disconnected the battery when it reached 'float' mode.

Looking at the details of the battery, the highest cell is 3.352v and lowest is 3.312v and a diff of .04v. After I put a load on the battery, it jumps down to 3.327v and 3.325v with a diff of .002v.

This is my first experience with batteries and charging, so I have no clue what I'm doing. I don't feel comfortable with opening the box and fiddling around with the insides. My gut is telling me that my absorption voltage may be set a bit too high, causing the battery to stop accepting a charge, and showing the interrupted state on the charger, which doesn't balance the cells.

Am I on the right path with this, or is there a bigger issue?
Everything you posted is absolutely normal.

If you wish to assess cell health, we need a capacity test result. These voltages mean nothing without capacity test results.
 
I think what Meetyg means by "balance current", is the amount of current that the BMS is able to draw from the battery/charger combination to keep its voltage down. The BMS will use a certain resistor value to draw down each battery but can only draw so much due to the size and resistance of that passive balancing resistor.

By keeping the maximum charge current down, the BMS should be able to keep up with that low-ish current
Or you can just cycle it like normal and wait a few weeks. It will balance.
 
Did no one notice the cycle count here is zero?
View attachment 95674

Try cycling it 20 times and leaving it at high soc and give it a month. This is very common on new batteries. It takes a few weeks for a passive dissipative balancer to do its job.

Don't use an active balancer, those are a waste of money. Let the BMS balancing circuit work it out.

I think people should stop checking their cell voltages. Do a capacity test and see what it pulls. If it does not pull full capacity, return it.

Thanks for the reply. Not the OP but seeing similar things with my battery. Honestly, the battery is new and part of me had a feeling that things will work out in the long run. Being new though, I have no idea what I'm doing. :D

One question, what increases a cycle count? I ask because I charged the battery when it arrived and it 'woke up'. Then I fully discharged it until the BMS cut the power (D CMOS). Fully charged it until the BMS kicked the charger power (C CMOS). Somehow though, my cycle count is still zero. I would had thought that the full charge/discharge/charge would increase the cycle count.
 
Well, I tried the parameters and the charge now says 'completed' instead of interrupted....which is a good sign. Unfortunately though, it looks like the cells may still be out of balance, which was what the OP was talking about.

HV: 3.706v
LV: 3.38v
DV: .326v

Is this something I should be concerned about? Keep an eye on it? Adjust another setting?
3.706 is a bit high. I would drop one more tenth on the charge voltage and simply use the battery. In time it may balance but it could be a looong time, maybe a year or more depending on use.

If the battery balances during float..... Consider floating at 13.90 volts with storage remaining at 13.2-13.4 range. Check monthly if the delta improves. Post the results.

I like active balancers but I would not add one unless the battery was DIY built.
Send a message to SOK and get some feedback on how to proceed.
 
In your case I would do the following:
Stop all charging, and use the batteries untill you get to a low voltage (below 3v per cell).
Then charge the batteries separately with a decent amperage up to about 80-90% SOC (3.4v per cell). Then charge them SLOWLY (still separately, say no more than 1A), up to 100%. This slower charging at the top should allow the balance current to keep up with the charge current. I'm not sure what the balance current on the SOK is, but maybe you will need to go even lower on the charge current.
^ 100% what I would do, if the first run with them together didn't yield results (shouldn't be a problem since they're in parallel and same capacity, should be hitting 100% roughly simultaneously); would want to keep my eye out to see how the cells behave after a couple cycles. I do know SOK likes people to do at LEAST 2 cycles before concluding on capacity/charge/discharge issues per their documentation on their site and posts I've seen.
 
Thank you all for this thread! I'm helping a friend out with her van electrics, and she (somewhat on my recommendation) bought a pair of SOK 206Ah batteries. I've got them at my house, I just got both charged up, and noticed this same cell imbalance (though only .174 delta at most) on one pack.

I'll definitely be checking up on these packs in the next weeks once they're installed and in use.
 
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