SOK 48V100 losing AH capacity

[alsatvs]

You are controlling the CHARGING and therefore you can set your charging parameters.
That NONSENSE about 50% discharge limit, that is LEAD ACID BATTERY related and NOT Lithium Chemistries. LFP is absolutely perfectly safe to use 100% of it with absolutely NO DEGREDATION.

I've been at this for years, built, assembled & delivered a LOT of battery systems and installed some pretty wild stuff over the years. I never ever promo my business or my doings on here, I am busy enough and don't need the hassle BUT I still come here to help when possible.

Change your settings on the Charger Subsystems (SCC, Inverter/Charger or AIO) and as long as you stay within the Allowable Range you will cause no harm but if you work with respectable Working Range you will have few if any issues. I've contributed to what I can in this thread, Have a Great Day.,,

Then why do the manufacturers who dont know as much as you state that you get more cycles out of them depending on depth of discharge.Iam now starting to believe that none of the people reading this discussion are reading it and it says at the top the page FORUM MEMBERS PLEASE STAY ON TOPIC CHECK OUT THE CHIT CHAT ZONE.AND DONT TELL ME WHAT THE WARRANTY STATES ON MY SOK BATTERY I READ IT YOU CANNOT CHANGE THE PARAMETERS PERIOD

 

[Lt.Dan]

Then why do the manufacturers who dont know as much as you state that you get more cycles out of them depending on depth of discharge.Iam now starting to believe that none of the people reading this discussion are reading it and it says at the top the page FORUM MEMBERS PLEASE STAY ON TOPIC CHECK OUT THE CHIT CHAT ZONE.AND DONT TELL ME WHAT THE WARRANTY STATES ON MY SOK BATTERY I READ IT YOU CANNOT CHANGE THE PARAMETERS PERIOD

It's true. 100% discharge with LiFePO4 is perfectly safe and will not degrade any faster than 50%.

If you want to argue and type EVERYTHING IN ALL CAPS, WE ARE GOING TO BE LESS RECEPTIVE TO HELPING YOU, AND YOUR CREDIBILITY WILL GO OUT THE WINDOW.

 

[alsatvs]

While I don't agree with the 3.7v disconnect the SOK does, it's not causing crazy irreparable damage immediately. Especially if you are charging at 100a and it hits 3.7v. When that happens, I bet it's back to 3.5v in a matter of seconds, and settles below 3.4v in a few minutes.

If the battery is short 3.5ah, and is out of balance, I can't imagine calling it garbage and saying that QC was gone that day and it shouldn't have been sent out. Balance the damn battery and use it.

I never charge my batteries at 100A so dont assume I do .IN fact I like to keep it around 20A and IN the picture I posted it does not show it but it was at 5A and what would call this battery sir.HERE let me give you an analogy YOU buy a new car and theres a problem guess what buddy fix your damn car and use it yourself

 

[Steve_S]

Last Post in this mess.

Understand that YOU are in control of the parameters of your Solar Controller, Inverter & Charger... NOT THE BATTERY !
If the battery is set to take up to 57.5V (3.600 Vpc) and you CHOOSE to only charge to 55.2V that is YOUR CHOICE !
A 100AH Battery Pack can take a max of 50A Charge or 0.5C. LFP is designed & rated for this.
4 Packs in Parallel can absorb 200A in total for charging and can dump 400A between them without a blink.
MANY have hit the Locked BMS issue with SOK, LiTime and others using PACE BMS' who love to lock down.

Lastly, some of us are in this business, we do have some idea about it. A few of us even work WITH the companies producing these BMS' to improve their hardware, documentation and much more. THIS SITE HAS A LOT OF TRUE Tech's involved, not just hobbyists.

Last Tidbit which many do not understand. The lowest Common Denominator RULES !
IE: 4 Packs in Parallel, 3 packs can reach 55.2V but one will only get to 53.6V, as soon as charging is done, the other packs will attempt to backfill the lowest and in doing so with de-energize to that packs voltage level. This can be caused by something as simple as one dud cell, or even a bad connection to a cell.

 

[alsatvs]

It's true. 100% discharge with LiFePO4 is perfectly safe and will not degrade any faster than 50%.

If you want to argue and type EVERYTHING IN ALL CAPS, WE ARE GOING TO BE LESS RECEPTIVE TO HELPING YOU, AND YOUR CREDIBILITY WILL GO OUT THE WINDOW.

SIR I am not using capital letters to argue Iam using to magnify the situation or point

 

[Lt.Dan]

I never charge my batteries at 100A so dont assume I do

I was using 100a as an arbitrary example. Even charging at 20a, hitting 3.7v will drop back down to 3.5v in a couple minutes.

YOU buy a new car and theres a problem guess what buddy fix your damn car and use it yourself

Please show that your supplier has told you this. This forum LOVES to trash suppliers when they are truly in the wrong. It seems @HighTechLab is working on something, but it is the holidays and I'm sure he's out of the office. Patience is recommended.

SIR I am not using capital letters to argue Iam using to magnify the situation or point

I am finished with this thread as well. Your supplier is responsible for your tech support, not us. Please reach out to them and return to this thread if you have been provided a solution or not.

 

[alsatvs]

Last Post in this mess.

Understand that YOU are in control of the parameters of your Solar Controller, Inverter & Charger... NOT THE BATTERY !
If the battery is set to take up to 57.5V (3.600 Vpc) and you CHOOSE to only charge to 55.2V that is YOUR CHOICE !
A 100AH Battery Pack can take a max of 50A Charge or 0.5C. LFP is designed & rated for this.
4 Packs in Parallel can absorb 200A in total for charging and can dump 400A between them without a blink.
MANY have hit the Locked BMS issue with SOK, LiTime and others using PACE BMS' who love to lock down.

Lastly, some of us are in this business, we do have some idea about it. A few of us even work WITH the companies producing these BMS' to improve their hardware, documentation and much more. THIS SITE HAS A LOT OF TRUE Tech's involved, not just hobbyists.

Last Tidbit which many do not understand. The lowest Common Denominator RULES !
IE: 4 Packs in Parallel, 3 packs can reach 55.2V but one will only get to 53.6V, as soon as charging is done, the other packs will attempt to backfill the lowest and in doing so with de-energize to that packs voltage level. This can be caused by something as simple as one dud cell, or even a bad connection to a cell.

Thank you I do know I can disconnect the communication cable between battery and inverter and all my inverters allow me to control the charging voltage so yes Iam in control from that perspective.Almost evryone here except Dexter from Current Connected and maybe 1 or 2 others missed the point.There is a problem with a new warrantied battery.I asked the forum if anyone else was having this problem.And since everyone knows more than I (I dropped out of kindergarden LOL) how come no one can see there is a problem with this battery with the evidence right before their eyes.If you get sent a bad set of cells do you fix them or do you seek compensation for them from the supplier.Iam not denying some of the information given is good or bad(other than I dont have to fix a warrantied battery) but most information does not apply,and for you Steve S really is the advice not to communicate between battery and inverter by programming inverter to control battery For surely you know if communication is present the BMS tells the inverter the parameters which with SOK 48V100 is 57.6V at 45A so disconnect the communication and use your inverter because your in control does that fix my problem for my new battery (dont tell any one but I did that a long time ago at 150cycles and used 56V).I think not my battery still has a problem and any of the people in the business who should know better should be advising fix it under warranty.Which puts us back at were we started.Does anyone have a SOK 48V100 server rack battery that is losing AH Thanks

 

[Alkaline]

Hi Alkaline.I hope you dont mind but I took the liberty to read a bunch of your comments and discussions on the DIY forum.Iam sure you realize this is not a discussion about people buying cells from alibaba and what AH did they get out of this cell or that cell and what AH did they get out the battery they made or which cells are better or which supplier to buy from.This is about a battery that was bought from a reputable company ITs a SOK 48V100 server rack battery that started out as a bunch of Ganfeng 100AH cells where technicians tested all the NEW Grade A cells with nice original QR codes and no bloating.They put together 16 cells as a set to make THIS ONE BATTERY and then tested it for its capacity and put this capacity on a quality control sheet that came with the battery.and they guaranteed it and gave it a 10yr warranty.Yes it does lose capacity as it ages over 1000's of cycles,BUT IT DOES NOT LOSE 3.9AH IN 200 CYCLES UNLESS SOMETHING IS WRONG WITH THE BATTERY.I would be willing to bet 100AH(LOL) that the majority of SOK 48V100 owners have a battery that not only works excellent but still has the stated capacity on its quality control sheet after a lot more than 200 cycles.Further more IT IS OBVIOUS IN THIS DISCUSSION THAT MY BATTERY HAS A PROBLEM AND IF IT BALANCED THE CELLS AS IT CHARGED TO 57.6V INSTEAD OF GOING INTO OVP AND DISCHARGING ITSELF TO 53.8V IT WOULD EASILY GET THOSE 3.9AH BACK. In fact, if the technicians who tested my battery did not miss that there was a problem with it and instead installed a bank of cells 1 to 8 that matched the bank of cells 9 to 16 I would probably have a typical 106AH battery and we would not be having this discussion.THANKS FOR YOUR INPUT BUT IT DOES NOT APPLY HERE and I HOPE YOU ARE THRILLED WITH MY RESPONCE

You can read the ganfeng datasheets here:

Ganfeng Cell Datasheets

11133202 30Ah Pouch pdf 84162227 42Ah Pouch pdf A51 86Ah Prismatic pdf A09 100Ah Prismatic pdf A13 206Ah Prismatic pdf 71173204 280Ah Prismatic pdf

diysolarforum.com

I don't see a discharge curve but I'll show the EVE as a comparison, so the loss is the highest when the cells are new and as they age the loss happens less. So yeah I think 3.5Ah loss after 200 cycles is very reasonable.

If this was grade B I bet that loss would have been closer to 20AH or maybe even 30AH.

You are lucky to have SOK and current connected provide you with batteries state side, I can assure the forum is filled with horror stories from Alibaba scam batteries, go read about Taico and other baloney brands, dead batteries after just 5 cycles.

The other option would be to DIY your own.

 

[alsatvs]

You are controlling the CHARGING and therefore you can set your charging parameters.
That NONSENSE about 50% discharge limit, that is LEAD ACID BATTERY related and NOT Lithium Chemistries. LFP is absolutely perfectly safe to use 100% of it with absolutely NO DEGREDATION.

I've been at this for years, built, assembled & delivered a LOT of battery systems and installed some pretty wild stuff over the years. I never ever promo my business or my doings on here, I am busy enough and don't need the hassle BUT I still come here to help when possible.

Change your settings on the Charger Subsystems (SCC, Inverter/Charger or AIO) and as long as you stay within the Allowable Range you will cause no harm but if you work with respectable Working Range you will have few if any issues. I've contributed to what I can in this thread, Have a Great Day.,,

You can read the ganfeng datasheets here:

Ganfeng Cell Datasheets

11133202 30Ah Pouch pdf 84162227 42Ah Pouch pdf A51 86Ah Prismatic pdf A09 100Ah Prismatic pdf A13 206Ah Prismatic pdf 71173204 280Ah Prismatic pdf

diysolarforum.com

I don't see a discharge curve but I'll show the EVE as a comparison, so the loss is the highest when the cells are new and as they age the loss happens less. So yeah I think 3.5Ah loss after 200 cycles is very reasonable.

If this was grade B I bet that loss would have been closer to 20AH or maybe even 30AH.

You are lucky to have SOK and current connected provide you with batteries state side, I can assure the forum is filled with horror stories from Alibaba scam batteries, go read about Taico and other baloney brands, dead batteries after just 5 cycles.

The other option would be to DIY your own.

Thank you I believe I can build a better battery with the 280AH box with wheels and 280AH or 302AH eve cells for less than what I payed for this SOK 48V100.Not only that but I get to program the BMS parameters and have almost 3 times the capacity

 

[alsatvs]

I was using 100a as an arbitrary example. Even charging at 20a, hitting 3.7v will drop back down to 3.5v in a couple minutes.


Please show that your supplier has told you this. This forum LOVES to trash suppliers when they are truly in the wrong. It seems @HighTechLab is working on something, but it is the holidays and I'm sure he's out of the office. Patience is recommended.


I am finished with this thread as well. Your supplier is responsible for your tech support, not us. Please reach out to them and return to this thread if you have been provided a solution or not.

Its funny I ask if anyone is having a problem with a SOK 48V100 battery losing AH and people get off topic sir I did not ask for peoples tech support really Iam finished with this thread as well your supplier is responsible for your tech not us

 

[exmarkretired]

Its funny I ask if anyone is having a problem with a SOK 48V100 battery losing AH and people get off topic sir I did not ask for peoples tech support really Iam finished with this thread as well your supplier is responsible for your tech not us

I have 4 SOK 48v100. 3 are at the same capacity they started with. The other one has lost 4.5AH. I found the original inspection sheets. (102.6 - 98.1 = 4.5 I believe)

I performed the "reset" or relearn method Dexter stated in this thread. I am still 4.3% down from"new" According to a normal degradation chart Dexter posted the link to, it is losing capacity faster than expected. I called CC . A Very nice and polite person handled the call. Unlike my experience with another vendor so often referred to in this forum... I will post when they contact me and the results are in....

 

[alsatvs]

Hi Thanks for your reply.Have you watched the battery charge up on a PC.I have determined on my battery like starting from the picture I posted and then after charging stops that my battery discharges down to about 53.8V because the BMS is in protect mode and discharges until the voltage difference between the highest and lowest voltage of the cells is less than 30mV or balance (delta)Vcell(mV).I also noticed that battery goes to 100% at the FCC which on mine is like 96.6AH but yet the battery continues to charge for a while after that,yes the cell voltages keep increasing just not balanced some well over 3600mV and some well under 3500mV,which means if my battery was working properly in the first place,I would probably have my 100.5AH capacity back or more capacity back like a typical 106AH battery .In layman's terms at 200cycles I dont think my battery has lost this much capacity,its just not working right,which by observation of the battery operation is a fact,I noticed Dexter's graph is degradation is for when the battery is is discharged 100% every time something most of us will not be doing.I would like to point out that charging rates, state of charge, cycling conditions, temperatures and cell chemistry interact to determine battery degradation.Further more the fastest rates of degradation will be when batteries are cycled from 0% state of charge to 100% state of charge, at high temperatures, and high discharge rates something I can say is not happening at my house with my battery.So take notice I doubt your degradation is described by Dexter's chart,but only you know how you use your battery.I also would like to point out that you can google degradation of LiFePO4 batteries (its allowed here) and then you may not want to listen to what some of the people on here in this discussion are saying.Thanks and good luck

 

[Steve_S]

If you can monitor the BMS as that one battery pack is charging and at near full state.
- Can see if all the cells are at or near the same voltage or is one or more running higher voltage than the others ?
- If YES, have you watched it until one has reached High Volt Disconnect of 3.650 Volts ?
At that moment the BMS will register that it is at 100% by the way.
- When that cell reaches 3.650 the BMS cuts off charge until it hits the recovery voltage, what are the voltages of the other cells ?
- If they are at say 3.350 +/- & the one is HIGH, the Battery Pack will end up reducing that 1 Hi Cell to 3.350 ish post charge, and THAT is capping the battery pack.

Here is an ever worse end result of 1 "sick" pack in Parallel.
You can charge all the packs to 56.0V, they can all show 56.0V at the terminals when done.
Then the 1 sick pack, with 15 cells @ 3.35+Varied & 1 @ 3.6x, will immediately try to pull from the other packs as it tried to balance the cells internally while also pulling down the Hi cell. The end result as it pulls down the Hi cells & others to balance, it will also pull down the neighbour packs because the voltage across the bus forces that... Once all pack reach "equilibrium" their output amperage will match up from that point forward. The weakest cell in a pack, can affect an entire bank of batteries. In the end when that entire cycle is over, several AH's have been wasted off the Total AH's as a result.

 

[alsatvs]

If you can monitor the BMS as that one battery pack is charging and at near full state.
- Can see if all the cells are at or near the same voltage or is one or more running higher voltage than the others ?
- If YES, have you watched it until one has reached High Volt Disconnect of 3.650 Volts ?
At that moment the BMS will register that it is at 100% by the way.
- When that cell reaches 3.650 the BMS cuts off charge until it hits the recovery voltage, what are the voltages of the other cells ?
- If they are at say 3.350 +/- & the one is HIGH, the Battery Pack will end up reducing that 1 Hi Cell to 3.350 ish post charge, and THAT is capping the battery pack.

Here is an ever worse end result of 1 "sick" pack in Parallel.
You can charge all the packs to 56.0V, they can all show 56.0V at the terminals when done.
Then the 1 sick pack, with 15 cells @ 3.35+Varied & 1 @ 3.6x, will immediately try to pull from the other packs as it tried to balance the cells internally while also pulling down the Hi cell. The end result as it pulls down the Hi cells & others to balance, it will also pull down the neighbour packs because the voltage across the bus forces that... Once all pack reach "equilibrium" their output amperage will match up from that point forward. The weakest cell in a pack, can affect an entire bank of batteries. In the end when that entire cycle is over, several AH's have been wasted off the Total AH's as a result.

I refer you to the picture I posted and what capacity have you lost on your SOK 48V100 battery

 

[Steve_S]

I refer you to the picture I posted and what capacity have you lost on your SOK 48V100 battery

You have 7 cells above 3.6x with 9 hovering between 3.4x to 3.5.
You need to stop charging above 3.500Vpc / 56.0V.
They will reach that point and balance out without triggering HVD (hopefully) and you will have 100% capacity. By charging higher you are handicapping the pack.

Your EndAmps is 5A, that means that as you charge & the amps taken drops to 5A going into the pack, it is full and ready to float for the final 5% topoff.

The chemistry is what it is, you cannot force it to do otherwise or to take more than it's design. Attempting to do so will actually cost you energy if you force a pack and it misbehaves as a result.

 

[alsatvs]

You have 7 cells above 3.6x with 9 hovering between 3.4x to 3.5.
You need to stop charging above 3.500Vpc / 56.0V.
They will reach that point and balance out without triggering HVD (hopefully) and you will have 100% capacity. By charging higher you are handicapping the pack.

Your EndAmps is 5A, that means that as you charge & the amps taken drops to 5A going into the pack, it is full and ready to float for the final 5% topoff.

The chemistry is what it is, you cannot force it to do otherwise or to take more than it's design. Attempting to do so will actually cost you energy if you force a pack and it misbehaves as a result.

and you are the guy who said "When that cell reaches 3.650 the BMS cuts off charge until it hits the recovery voltage,"

 

[Steve_S]

and you are the guy who said "When that cell reaches 3.650 the BMS cuts off charge until it hits the recovery voltage,"

Yes, that is exactly what a BMS must do.

Maybe we have a language issue here if you are using a translator. I have made every attempt to be as clear as possible, even for translator software. I have written several BMS manuals (Chargery, JK & Others) and build battery systems and have for a long time... I have given you the pertinent information and all of it is based on industry standards & facts....

So with it as you will. Use it, ignore it and continue suffering issues or whatever.

Hope it Helps, Have a Nice Day.

 

[Mattb4]

...

I've been at this for years, built, assembled & delivered a LOT of battery systems and installed some pretty wild stuff over the years. I never ever promo my business or my doings on here, I am busy enough and don't need the hassle BUT I still come here to help when possible.

...

I have always appreciated your posts. Your experience with liFePO4 batteries has help me with several areas in understanding them. My training in batteries were all lead acid so it has been a transition.

 

[alsatvs]

Yes, that is exactly what a BMS must do.

Maybe we have a language issue here if you are using a translator. I have made every attempt to be as clear as possible, even for translator software. I have written several BMS manuals (Chargery, JK & Others) and build battery systems and have for a long time... I have given you the pertinent information and all of it is based on industry standards & facts....

So with it as you will. Use it, ignore it and continue suffering issues or whatever.

Hope it Helps, Have a Nice Day.

I refer you once again to the picture but i will spell out for you what you failed to notice or make the connection if the BMS cuts off charging at 3650mV then how did cell #3 get to 3700mV this is what we call an "observation' .I appreciate you trying to help,but I asked what capacity you lost on your SOK 48V100 which you gave no reply but did reply with a unwarranted one.I would like you to write that in one of your several BMS manuals you have written.Thanks and have a great Day

 

[Steve_S]

When cell runs like they do, teh BMS cuts off at 3.650 but a weak cell can run above that in MILLISECONDS which is faster than a BMS will cutoff, there is a OVP Delay just like a LVP delay. I even have 1 cell that will run to 4.0V if I high charge over 3.5Vpc... It's getting recycled & replaced.

I do not run SOK packs, they are no different than a 1000 others... LFP is LFP and SOK is just an ASSEMBLER, they don't make cells, or BMS or anything else for that matter.

Given your continued hostile responses. This is my final post. Am placing you on ignore. So Bye Bye & Good luck with that Tude.