Also have similar question. I am trying your reset. However my battery is only 98Ah and IIRC never was 100Ah from day one. Have 4 SOK SK48V100 The battery in question BMS indicates it has more cycles, more OVP and more UVP than the other 3.... the other 3 batteries are still at 101,106 and 106.. after 63-67 cycles. The battery in question shows 71 cycles. Is this to be expected ?
I may be mistaken, but I think you are in Europe, right? I'm trying to figure out your place of purchase so the appropriate team can get you help.
Hi unfortunately my advice for a new 98AH battery is to return it immediately. like hightechlab says they are typically 106AH and your battery and mine probably have a bunch of 106AH(approximately) cells in them they are just not working together as a team to give a total capacity of 106AH approximately at 57.6V
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
I have been reassured by the supplier that SOK is working on this and Iam sure that I will be fully compensated for this battery.After all this is good business for SOK to show that they back their warranty and that this only happens to a small % of their total output,kind of like once in a while a bad battery can escape their factory and not a systemic problem.
Nice response.I dont like discharging my batteries more than 50% maybe 60% because as you know they will last longer.I also included a picture in this discussion of my battery charging up and Iam sure (I hope) you looked at it and can clearly(ok its a crappy picture but then I have to do this watch the battery charge up again and Iam sick of that,I dont use battery anymore it can sit at 55% for awhile) see cell #3 is at 3700mv and yes this cell is now damaged I know and its probably not the only one that went to 3700mv.I need to remind people here that the warranty is invalid if you change any parameters from the factory settings.YES I disagree with them on their settings and I am sure SOK will eventually get around to charging to 56V and 3500mv max per cell.AND I THINK YOU ALSO KNOW THAT THE BMS IS DOING THIS NOT ME.YES so telling us this is not helping me you should explain your chart to SOK because my problem is not of my doing and you now know I am not allowed to change BMS parameters.Thanks for your responseA few things here:
1) Temps DO AFFECT battery charge & retention. Stats are based on Optimal Temps being 25C/77F, even a 5 degree drop will affect the batteries slightly.
2) LFP like ALL Battery chemistries has an Allowable & Working Votage ranges. LFP Allowable is 2.500 -> 3.650 but the WORKING Range is from 3.000-3.400 Volts per cell.
3) The LFP Chemistry ALWAYS SETTLES post charge, this is normal & expected. It is also relative to the depth of charge saturation.
Charge Saturation is when a battery packs reaches EndAmps, then it is considered full. As resistance increases due to charge, the amps taken reduces till EndAmps is reached, at which point charge should transition to Float to complete the soft top-off.
4) Lastly ! When charging LFP over 3.425Volts per cell, this is where they will deviate and become unbalanced. Continually pushing cells over that threshold is not doing ANY good whatsoever and depending on the Balancing Systems can in fact be detrimental.
A Standard "48V" LFP charging profile which does not push the cells out to the edges is below.
Bulk & Absorb: 55.2V for (absorb timer 45 minutes) (3.45vpc) (some call this boost)
Equalize: OFF
Float: 55.0V (3.437vpc)
MIn Volts: 42.4V (2.650vpc)
Max Volts: 28.6 (3.575vpc)
Rebulk Voltage: 57.2V (3.200vpc)
End Amps/TailCurrent: 5.0A
BTW: When Battery Manufacturers test & certify the AH Capacity rating of the cells, this is done within the WORKING VOLTAGE RANGE. That is the 3.000-3.400 range @ 25C Temp that delivers the rated AH !
Oh and since you helped design it its time you gave a real hard look at your BMS parameters and change them start with 56V and 3500mv per cell max thats where you slam on the breaks your settings leave us slamming on the breaks when its toooooooo laaaaate and now my battery which I payed 3070 dollars for has damaged cells.Thanks
