Battery issues

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Is what you're saying here that a bad BMS ruined the cells permanently? Lovely haha.
Not necessarily, I'm speculating. The cells themselves can be the problem.
When something electrical fails sometimes similar symptoms can be caused by different failure points...or one failure causes then another.
To test the bms will shed further light on understanding what happened here.
In the end with cells that low in voltage, I'm not sure I would bother with a pack a few years old as any replacement cells would need to be closely matched for any reliability and safety.
 

stevet2233

New Member
Not necessarily, I'm speculating. The cells themselves can be the problem.
When something electrical fails sometimes similar symptoms can be caused by different failure points...or one failure causes then another.
To test the bms will shed further light on understanding what happened here.
In the end with cells that low in voltage, I'm not sure I would bother with a pack a few years old as any replacement cells would need to be closely matched for any reliability and safety.
What i've been looking for is how to test the BMS. I have no intent on replacing cells if they are damaged. Any bad cells and this whole thing goes bye-bye, but if a simple BMS swap gets me back up and running than im willing to do that
 

stevet2233

New Member
I dont understand how this was supposed to show us anything we didnt already know. We already knew that my charge and discharge ports were both getting power readings and that 1 cell was significantly lower than the rest, i did those checks, but they obviously just mirrored those same conditions. I keep on hearing that these results are "not necessarily" an indicator of one or the other, is there some sort of info I can provide that will make things more certain? google is great for finding testing methods, but isnt particularly great at explaining how to interpret the results of the test, this video is a prime example
 

tomjasz

Well-Known Member
I dont understand how this was supposed to show us anything we didnt already know. We already knew that my charge and discharge ports were both getting power readings and that 1 cell was significantly lower than the rest, i did those checks, but they obviously just mirrored those same conditions. I keep on hearing that these results are "not necessarily" an indicator of one or the other, is there some sort of info I can provide that will make things more certain? google is great for finding testing methods, but isnt particularly great at explaining how to interpret the results of the test, this video is a prime example
You’re welcome.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
I dont understand how this was supposed to show us anything we didnt already know. We already knew that my charge and discharge ports were both getting power readings and that 1 cell was significantly lower than the rest, i did those checks, but they obviously just mirrored those same conditions. I keep on hearing that these results are "not necessarily" an indicator of one or the other, is there some sort of info I can provide that will make things more certain? google is great for finding testing methods, but isnt particularly great at explaining how to interpret the results of the test, this video is a prime example
It's hard to pinpoint 100% as there are many different BMS's.. All of which have different parameters and safety features.
Like your charger... Some pulse, others do not.
But like I said previously... I would plug in the charger and see if you have output on all the charging leads.
A cell with 0.8v is more than likely damaged and/or has internally shut down for safety. There are methods to attempt restoration, but that'll require some research and most likely disassembly.
Also giving advice here is meant to help give you ideas on figuring it out and assuming you have some idea how things work since you are considering on doing the repair yourself.
 

stevet2233

New Member
You’re welcome.
Sorry, tone didnt come across right in that post (still waking up and am terrible at communicating through text in general) I didn't intend to sound unappreciative, just trying to understand what info you need/how i should interpret my readings, I dont know what else to say or check. If it just isn't possible to know in these circumstances then I'm fine with that answer and I'll scrap the battery/buy a new one, but if its just a BMS I'll replace it. just want to know whatever i need so i can get it ordered asap haha

Thanks!
 

stevet2233

New Member
It's hard to pinpoint 100% as there are many different BMS's.. All of which have different parameters and safety features.
Like your charger... Some pulse, others do not.
But like I said previously... I would plug in the charger and see if you have output on all the charging leads.
A cell with 0.8v is more than likely damaged and/or has internally shut down for safety. There are methods to attempt restoration, but that'll require some research and most likely disassembly.
Also giving advice here is meant to help give you ideas on figuring it out and assuming you have some idea how things work since you are considering on doing the repair yourself.
I have a decent understanding of the battery itself, the BMS is where i get confused, that is all im really looking for advice on. If there wasn't a BMS it would be clear as day that it would be the cell, but from what i do understand I agree that it is looking like the battery itself where the issue lies
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
No worries... Most don't get my twisted humor... Especially through text.
Testing electronics typically requires a manufacturer repair manual with specific parameters to look for.
That said.. an energized BMS should have an output to the battery as long as the cell voltage is below 100% - 4.2v/cell
That should show up as a slight increase in voltage at each cell when energized. And probably a better method would be to place the meter between the BMS and battery and see if you have current flow to the cell.
Sometimes a better way to research a problem is to Google how it works then how to test or repair it.. and then a lot of reading
 

stevet2233

New Member
No worries... Most don't get my twisted humor... Especially through text.
Testing electronics typically requires a manufacturer repair manual with specific parameters to look for.
That said.. an energized BMS should have an output to the battery as long as the cell voltage is below 100% - 4.2v/cell
That should show up as a slight increase in voltage at each cell when energized. And probably a better method would be to place the meter between the BMS and battery and see if you have current flow to the cell.
Sometimes a better way to research a problem is to Google how it works then how to test or repair it.. and then a lot of reading

there is current flow literally everywhere I have tried, which is basically everywhere possible at this point haha, the voltage is just drastically reduced any time the 1 problematic cell comes into play. Think I'm ready to accept that there is a dead cell and go cry myself to sleep hahaha.

Any recommendations out there for a good way to find a good quality battery? I'd rather just get a pack without a housing on it, but many of the ones I've come across seem... suspect lol (my favorite was the one that was supposedly 100Ah with 18650s in 13s3p, which is just blatantly impossible lol).

Also, anyone have experience with 21700 cells? I found one that should fit my case that seems somewhat legit but is made with the 21700 cells in 13s4P, which i have zero experience with, but I like the increased capacity haha.


Thanks!!
 
Last edited:

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Nethers Batteriesthere is current flow literally everywhere I have tried, which is basically everywhere possible at this point haha, the voltage is just drastically reduced any time the 1 problematic cell comes into play. Think I'm ready to accept that there is a dead cell and go cry myself to sleep hahaha.

Any recommendations out there for a good way to find a good quality battery? I'd rather just get a pack without a housing on it, but many of the ones I've come across seem... suspect lol (my favorite was the one that was supposedly 100Ah with 18650s in 13s3p, which is just blatantly impossible lol).

Also, anyone have experience with 21700 cells? I found one that should fit my case that seems somewhat legit but is made with the 21700 cells in 13s4P, which i have zero experience with, but I like the increased capacity haha.


Thanks!!
If you are looking for something to fit in that case there are battery rebuilds available.
Here's one Nethers Batteries
Search on here as I've come across threads mentioning it and then give Google a shot as well
 

tomjasz

Well-Known Member
I think UPP has a match. I’m not a fan, but my packs held up. I’m wrong to suggest EM3ev, they don’t build in your case style. Sorry!
 

stevet2233

New Member
If you are looking for something to fit in that case there are battery rebuilds available.
Here's one Nethers Batteries
Search on here as I've come across threads mentioning it and then give Google a shot as well
Definitely started with google on this, but it can be so hard to determine what is quality and what isn't, once the battery is wrapped it is hard to learn anything about it, I posted here to see other people's experience haha. Like when you're buying a pre-made battery there's no real way of knowing the individual cell manufacturer or if it is protected, which I'm sure we all know makes a dramatic difference with these large packs and 18650s in general haha.

I'll be looking into these links later on when i get back from work, thanks all!
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Definitely started with google on this, but it can be so hard to determine what is quality and what isn't, once the battery is wrapped it is hard to learn anything about it, I posted here to see other people's experience haha. Like when you're buying a pre-made battery there's no real way of knowing the individual cell manufacturer or if it is protected, which I'm sure we all know makes a dramatic difference with these large packs and 18650s in general haha.

I'll be looking into these links later on when i get back from work, thanks all!
At a certain point you'll need to trust the supplier and hope he's continuing to protect his reputation. That's why an established company with a good rep. is your best bet.
There's a certain cost involved with supplying a quality product and claims of providing more than you are paying for will probably end up biting you in the end.
UPP started off with a good rep. but as of late it has diminished a bit. It seems that they are trying to recover and build it back up but they're at the low end of what one would expect to pay for a good battery so I wouldn't go any cheaper than that.
 

stevet2233

New Member
getting really frustrated that it seems like such a huge percentage of batteries out there are sharks, i prefer the look of the silverfish, especially my black one, but I might switch for convince.

The primary thing that scares me about that is that my bike is a folder, so there isn't a horizontal location anywhere i could connect a battery to. This may be a moot point because i still need to take some measurements to see if one will even fit here, but I only have one practical place I could mount it and it is a roughly vertical surface. I know it is bad to mount sharks upside down, but is vertical a problem? This is also part of why I loved the silverfish haha

1619232041621.png