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Problems with charging (overcharge, voltage increased rapidly over 3.5V)

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without a true BMS, this project has little likelihood of success.
I am more positive than that. Due to the OPs mobility issues she has the ability to turn off the cells before the buzzer goes off. Given how fast these cells start running, I would suggest doing that when the first cell hits 3.45 or 3.5 volts.
My suggestion could save any additional expense for a more expensive Battery Management System that would automate the process. In essence the OP would be the high voltage cutoff monitor or manager.
 
I have top balanced them. Back in October.
I then used them and then charged them up to 3.5 and then used them again and then charged and then used them etc. And then the scooter broke. I got a new used scooter after a few weeks.
The batteries sat on the floor in their box I made for them in October after lowering the voltages 20%. Then I charged them up again like I said and used them over and over with no problems.
I decided to charge the batteries to 3.5 volts after I got the new used scooter. They were not yet connected to the scooter.
I started to charge them and they went nuts.
The rest is written earlier as to what happened.
Permission to PM please. I would like to assist if you will allow.
 
Not sure if you can squeeze it into your budget or what your exact needs (current rating, voltage) are, but there are some pretty cheap small Daly BMSes on (US) ebay, might be the same in Canada or they might ship to Canada.
 
Permission to PM please. I would like to assist if you will allow.
First, ask about the spray paint, or whatever is all across the tops of the terminals.
If nothing else, the cells need to be parallel top balanced, don't depend on a cheap "balancer", do a real parallel connect type balance on cells like this..
Likely at least some of the capacity of the cells remain, need to find out how much for each cell.
Looked like a 24 volt system, but doesn't the monitor she is using default to a different chemistry? (that could explain a lot)
Hard to make out, but she has two packs of 4 cells in series, cell 5 is at 4.2 and all others are ok.
I didn't spot any cell bloating, but really, that one cell is out of balance.
 
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I do not know how the OP ever got to this reasoning. She has posted about BMSs over 125 times since July (i searched!). Its a shame She did not mention that She was using an iSDT battery monitor thinking it was a BMS; we could have helped Her had we known (first mention of iSDT in post #40 above).

Hopefully Hers cells are ok and She somehow gets a BMS for Her battery.
And she was warned at least 125 times what would happen if she failed to use a BMS. Also she stripped some of the screws but has tapped them.

Ok putting you on ignore for being a repetitive moron. bye
You can put me on ignore too if you like. How do you expect to get any help if you keep putting people on ignore, calling them morons and dicks and whatever? You never know...one of those people you put on ignore might be of great help to you. You claim you are a senior...I am too. I think we should be acting like adults...don't you?

I will throw in my two cents in an effort to help you. And you will not like everything I am about to say because it appears you are looking for someone to agree with you that you have defective cells. I will not be that one. Have you put me on ignore yet...lol. If not continue to read.

In light of the fact all the cells have been through, I would drain them down and the do another parallel top balance. If your cells are not bloated when you remove to top balance then there is a good chance they survived. Take your time and think positively. I know it can be difficult. I felt bad when I stripped a stud in one of my cells. I can't blame that one on the supplier.

Next I would rebuild the pack. I would make sure the terminals, busbars and everything is clean and that you have good connections.

You said the cells were working properly for awhile and then things started to go wrong. Was that before or after you stripped your screws? And are the same cells that shoot up the same ones you stripped the screws? I am wondering if you have bad connections. BTW, what is that red stuff on your cells terminals? Did you use whatever it is to mark your terminals positive?

I will say I am disappointed. In the beginning everyone was warning you about the need for a proper BMS. It's possible you were misled about the iSDT. But when you noticed the cell shooting up the first time, you should have stopped everything then and asked for help.
 
While we can all relate to saying things we later regret when we are upset or frustrated or feel disrespected, we have a responsibility to one another and to ourselves to be respectful and constructive, even if we feel the other person isn't. Generally speaking we are not rude or disrespectful to one another here, even where we disagree, and we recognize that we all have things to learn from one another, and recognize that we all make mistakes. That is what makes this community so pleasant, and positive, and constructive and keeps us coming back.

Please refrain from personal insults, and consider the tone and intent of your response before hitting reply. There are many cases where I have caught myself writing something out of frustration or anger that I can later admit would not have been constructive to post, even if I felt justified or right in what I was saying.
 
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