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+100

Suspect that one didn't get processed like all the others OR it has very high IR. If they discharge them to a target voltage, and that is high IR, I wouldn't be surprised by a voltage bounce. Cell could be fine, but if the terminal wasn't properly fastened, it hit target voltage sooner than it should and bounced.

So tempted to test that one cell....



That one cell is likely at dramatically higher state of charge than the others meaning the usable capacity of that 16S battery is dramatically lower than the other due to absurd inter-cell imbalance.

I would take that one and the 15 other highest cells and set them aside. Leave those 16 wired in parallel together for an entire week. That would get them within 5-10% of each other. Build the battery and add it in parallel to the other 9 when they are at similar voltages.
Amy had sent a few videos before shipping showing voltage and internal resistance of all the cells , I don't remember seeing one that was that much different , I'm going to take another look at the videos to see if I spot anything .
Going to take your suggestion and set up the 9 banks of 16S and set aside the highest 16 and set them up in parallel for a while to see if they balance out .
 
Fascinating build @Barbuda Cottages . Would love to see pics of the whole system and history of it. Do you have a build threaded or a blog/vlog of the power generation for the property?

Good luck with the 160 cells. Following the advice of the collective wisdom here as I wait for my 16 cells.
Thanks, looking back at the solar journey of the past 14 years I really wish I had done a build thread or blog but unfortunately I have so many projects on the property that I never had time to put something like that together . I'll try to post some pics over the next few days .
Good luck with the batteries you are expecting !
 
That cell at 3.346 bugs me.
After the ir test do you have the ability to capacity test individual cells?
I would be interested to see the capacity of the odd one vs one that is not an outlier.
Unfortunately I don't have the ability to test individual cells
 
160 cells? Wow!!!! Thanks for taking the time to share. I hope you take the time to show the final construction too! I am very excited for your business! I love coming here and viewing big battery builds!
 
Thanks to everyone for the advice , I had the 9 banks all wired up on Sunday evening and made the switch over from the old batteries to the new Lifepo4 batteries , I decided to run the generator the first night as I would have done anyways with the old set , to give them a decent charge before starting their journey . I had left one bank of 16 cells connected in parallel since Saturday morning to balance out the one cell that came with the high voltage . This morning I checked on that bank and everything looked great so I connected these as well to complete the 160 cell system . I'm attaching a few pics of the system , still need to clean up some of the wiring and figure out how I want to properly mount the BMS's , the leads are very short and don't give many options .
 

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I think you set a new record for how fast you got those into operation. (y)
 
I think you set a new record for how fast you got those into operation. (y)
Thanks ! that was completely out of necessity ... and the great advice from everyone here on the forum who encouraged me to put most of them directly into service and let the solar system doing the balancing . Thankfully all except one cell was within .008 of a volt which was great .
The old battery bank was barely able to hold a charge for more then an hour after the sun went down . I was literally pulling dead battery cells out of banks every 2 weeks, making do with what I had left . For a while I thought I was going to have to run the generator 24 hours a day , while waiting the 3 months for the battery shipment to get here .
I really couldn't have been happier and more relieved to see them arrive .
 
Thanks ! that was completely out of necessity ... and the great advice from everyone here on the forum who encouraged me to put most of them directly into service and let the solar system doing the balancing . Thankfully all except one cell was within .008 of a volt which was great .
The old battery bank was barely able to hold a charge for more then an hour after the sun went down . I was literally pulling dead battery cells out of banks every 2 weeks, making do with what I had left . For a while I thought I was going to have to run the generator 24 hours a day , while waiting the 3 months for the battery shipment to get here .
I really couldn't have been happier and more relieved to see them arrive .
Congrats on a successful implementation!
 
So if you bought a bench power supply that was 30 V and 60 A. Then you have a 3.65 V battery, with 32 in parallel to balance, your voltage setting would always remain at 3.65 as the top limit, but you could crank the amps up to 40 or 50 A for faster charging if you have a large battery bank like as described in this thread?
Or is it possible to turn the voltage up as well above the 3.65 v?
 
So if you bought a bench power supply that was 30 V and 60 A. Then you have a 3.65 V battery, with 32 in parallel to balance, your voltage setting would always remain at 3.65 as the top limit, but you could crank the amps up to 40 or 50 A for faster charging if you have a large battery bank like as described in this thread?
Or is it possible to turn the voltage up as well above the 3.65 v?

Turning the voltage beyond 3.65v is like playing Russian Roulette.
 
I was thinking you could, but how would you know when the charger is finished? Could very overcharge your cells....
I was almost positive not to go over 3.65 v.

Just don't do it .... always adjust to 3.65 with the power supply disconnected and then connect if with GOOD connections and don't touch it again til done.

Quite a few have thought they could get away with it only to have ruined cells.
 
I was thinking you could, but how would you know when the charger is finished? Could very overcharge your cells....
I was almost positive not to go over 3.65 v.
Yes, you can do anything you want especially if you want to join me and others who have overcharged their cells. I was sure I could watch them but something happened (Murphy's Laws applies). The problem occurs because voltage spikes very quickly after 3.55 and that was exactly when I fell asleep or forgot.
 
Yes, you can do anything you want especially if you want to join me and others who have overcharged their cells. I was sure I could watch them but something happened (Murphy's Laws applies). The problem occurs because voltage spikes very quickly after 3.55 and that was exactly when I fell asleep or forgot.
I guess the way I should’ve worded that was like this: I was thinking that you could, but it’s better that you do not. Cant afford more batteries!!!
 
I guess the way I should’ve worded that was like this:
I understood that you got the concept. I was taking the opportunity to point out to future readers the risks of setting a higher voltage. Even after 10 years of playing with Lithium cells I still make mistakes.
 
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