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

[Deleted member 9967]

[Moderator Note]: This thread began here and has been moved to its own dedicated thread:
[Moderator Note 2]: This thread has been locked and has been heavily edited due to an overwhelming number of less than excellent comments made out of anger/frustration/emotion. The flow of conversation may not make sense to future readers as many posts have been deleted or edited by the moderators. Please try to be respectful to one another (especially when in need of help), supportive, compassionate, and open to changing your mind. While this thread showed what happens when frustration takes control, it also exhibits the good side of this community, the willingness to try to help others and to learn and teach. Lets try to embody the latter going forward. Bottom line, personal insults are not acceptable. We are usually better than this.

Maybe that is why three cells have gone bad in only 3 months.
I got the old stock.
Dang

Dear Sherylin,

I just saw your email. No, I'm talking about the old version, but not saying that these are old batteries.

You use a BMS, but there is no a cut off relay. Did you turn off the charging after it turned on the red light to alarm?

Please stop charging now! The voltage of the 3pcs batteries has reached 4V, which has exceeded its maximum cut-off voltage: 3.65V. If you continue to charge, these batteries will swell, which will be unsafe.

If you use a relay with self-protection function, the voltage of these batteries will not exceed 3.65V.

The video link you sent is Youtube. Perhaps due to the restrictions of the Chinese network, I cannot open it. I know that it can be done using a special network. Regarding it, I need to ask my friend for help tomorrow.

I will reply to you again after opening the video tomorrow.

I turned it off immediately yes.
I was sitting beside them as they were charging. have a tiny place.
Anyhow, it only took about ten minutes for the bad cells to go from 3.34 to 4.2 volts. The other cells never moved in that ten minutes.

Also, if the cells were not bad cells then the voltages would never go above 3.65 as the power supply is set actually so that they should not go above 3.5 volts. So blaming the BMS for the cells going above 3.5 volts is not good. The cells should never go above 3.5 volts if the voltage going into the cell is 3.5 volts.

Anyhow, I immediately stuck a balancing on the cells to lower them so they only stayed high for a very short time. But it is disturbing.

Thank you for watching the videos when you can.

 

[Ampster]

For those that do not know China restricts access to Google, Youtube, Facebook and some others. When I travel in China I have to use a VPN to read my email.

 

[Deleted member 9967]

For those that do not know China restricts access to Google, Youtube, Facebook and some others. When I travel in China I have to use a VPN to read my email.

Yeah I do know. I did a small amount of security on computers once and learned a LOT.
Scary stuff.
Anyhow, you are correct. Also many other countries do something similar as well.
Thanks though for the heads up for everyone else that may not have known.

 

[upnorthandpersonal]

@Amy Wan (Luyuan) Could you try lbry.tv or odysee.com and see if that is available?

 

[Ampster]

Also, if the cells were not bad cells then the voltages would never go above 3.65 as the power supply is set actually so that they should not go above 3.5 volts.

If cells are in series it is very easy for one cell to go beyond 3.5 even though the voltage is only a multiple of 3.5.

 

[Steve_S]

LiferPo4 cells maximum recommended charge voltage IS 3.650V.

• They can easily be overcharged to 4.0V or higher. By 3.750 Volts damage is being caused.
• NO LFP Cell can "Restrict" the voltage it takes, it is after all just a "stupid cell" without intelligence.
• It is STRICTLY The BMS' job to control & regulate charging & disconnection. ANY Battery Pack assembly without a BMS has NO WAY of stopping a charge at any given voltage or amperage.
• An LFP Cell will increase it's voltage beyond 3.650 VERY QUICKLY if a higher voltage is pushed at it.
• Once an LFP cell has been overcharged above 3.750 it's long term performance will be immediately affected.
• If overcharged at High Amps above 4.00V they will begin to bloat and may possibly pop their vents at which time, they shoudl be sent to Recycling.

NO POWER-SUPPLY should be absolutely trusted until it has been thoroughly tested and verified.
Power Supplies such as MasTech, TekPower and similar with DIAL controls must be handled delicately, the settings are "twitchy" at best. Once set and as batteries reach full, careful & cautious continuous monitoring is required. as the Charge Amperage falls the voltage goes higher, once it really slows, you are reaching the end, then dol the "fine adjustment" checking with DMM to ensure you are NOT crossing 3.650V. Digital Power-Supplies must ALSO be checked when reaching the goal voltage for accuracy, against a Known Good Digital Multi-meter.

 

[Deleted member 9967]

If cells are in series it is very easy for one cell to go beyond 3.5 even though the voltage is only a multiple of 3.5.

Ok so ten minutes after starting a charge then is enough to cause them to go awry?
So then why does anyone trust ANY charger then?
If after ten minutes your cells can explode. Why is any charger not sold with a BMS with relays? And why do they sell them without a warning your cells may explode after a few minutes?

Makes no sense that you need a BMS with relays just to charge your cells. I NEVER had this problem with lead acid batteries.

Seems I wasted over a year saving up my money for these if charging them is GUARANTEED to kill the cells 100% of the time without relays etc.

 

[Deleted member 9967]

LiferPo4 cells maximum recommended charge voltage IS 3.650V.

• They can easily be overcharged to 4.0V or higher. By 3.750 Volts damage is being caused.
• NO LFP Cell can "Restrict" the voltage it takes, it is after all just a "stupid cell" without intelligence.
• It is STRICTLY The BMS' job to control & regulate charging & disconnection. ANY Battery Pack assembly without a BMS has NO WAY of stopping a charge at any given voltage or amperage.
• An LFP Cell will increase it's voltage beyond 3.650 VERY QUICKLY if a higher voltage is pushed at it.
• Once an LFP cell has been overcharged above 3.750 it's long term performance will be immediately affected.
• If overcharged at High Amps above 4.00V they will begin to bloat and may possibly pop their vents at which time, they shoudl be sent to Recycling.

NO POWER-SUPPLY should be absolutely trusted until it has been thoroughly tested and verified.
Power Supplies such as MasTech, TekPower and similar with DIAL controls must be handled delicately, the settings are "twitchy" at best. Once set and as batteries reach full, careful & cautious continuous monitoring is required. as the Charge Amperage falls the voltage goes higher, once it really slows, you are reaching the end, then dol the "fine adjustment" checking with DMM to ensure you are NOT crossing 3.650V. Digital Power-Supplies must ALSO be checked when reaching the goal voltage for accuracy, against a Known Good Digital Multi-meter.

It took 10 [that is ten] minutes for the cell to go from 3.34 to 4.2
I suppose EVERYONE has had the same problem then if it is that prevalent.
Ten minutes to destruction and the cell is not a bad cell?
Something sounds off here.

Oh yeah, I was only charging to 3.5 volts as well. NOT 3.65 volts.

 

[Gazoo]

The cells should never go above 3.5 volts if the voltage going into the cell is 3.5 volts.

The cells can't go above 3.5 volts if the voltage going into the cell is 3.5 volts.

 

[Deleted member 9967]

The cells can't go above 3.5 volts if the voltage going into the cell is 3.5 volts.

According to Ampster and SteveS though it can.
Because three of mine did. So maybe the cells are bad? Hmmm.
Just a thought.

EDIT: The powersupply I am using is the LONGWELL 30 volt, 10 amp version.

Anyhow, I am waiting to see from Xuba [who read my chat but hasn't responded] what will be done.

 

[Ampster]

Seems I wasted over a year saving up my money for these if charging them is GUARANTEED to kill the cells 100% of the time without relays etc.

The examples that you cite as unusual are all here on the pages of this forum. The answers are all here as well. There are no garantees in life but there are batteries like Battleborn and others that, for a price, will garantee that charging their batteries will not kill them.

 

[Ampster]

The cells can't go above 3.5 volts if the voltage going into the cell is 3.5 volts

The only way to insure that only 3.5 volts is going into a group of cells is to wire them in parallel.

The powersupply I am using is the LONGWELL 30 volt, 10 amp version.

 

[Deleted member 9967]

The examples that you cite as unusual are all here on the pages of this forum. The answers are all here as well. There are no garantees in life but there are batteries like Battleborn and others that, for a price, will garantee that charging their batteries will not kill them.

I spent ten percent of my annual income on these cells on the recommendation of the people here. It would take me years to afford new cells. And in the mean time I would be a shut in and not able to go outside.
Also, one person says one thing and another says something else. It is just confusing after a while and it seems that no one really knows what the answer is.

In the end this will either be fixed and made ok. Or I will be screwed and back to being immobile and a shut in.
After six years of being a shut in and then being mobile for a few months.
Going back to being a shut in I think would kill me inside.

We will see how it goes though.

 

[Gazoo]

According to Ampster and SteveS though it can.

Yeah they are correct. Sorry I need to wake up...lol. Sorry you are having all these problems. I thought you bought another scooter so you could get around? BTW, were you able to repair the stripped screws in any of your cells? I stripped one too so I know how it feels.

 

[Deleted member 9967]

Yeah they are correct. Sorry I need to wake up...lol. Sorry you are having all these problems. I thought you bought another scooter so you could get around? BTW, were you able to repair the stripped screws in any of your cells? I stripped one too so I know how it feels.

I did buy another scooter. But it still needs batteries to run it. Just as if you bought another car. It would still need gas. And well, a battery too.

And yes, someone sent me a die to make new threads and then I just cut some threaded rods to length, used some RED locktight and it works fantastically. I love it.

 

[Dzl]

Should some of this conversation (troubleshooting Sherilyns issues) be moved/taken to a different thread?

 

[Ampster]

Should some of this conversation (troubleshooting Sherilyns issues) be moved/taken to a different thread?

Yes, especially with a heading that might help others avoid the same issues of overcharging a cell when in series.

 

[Deleted member 9967]

To the moderator that moved this. Thanks

 

[Ampster]

@SherylinRM , how can we help?
Lets start with the assumption that you caught the problem in time and your cells are not damaged. I have done the same and still have good cells.

 

[Deleted member 9967]

Well I was charging them beside me [my room is small] and after less than ten minutes the alarms all went nuts and I turned everything off. The BMS said the cell was very high so I took my multi-meter and it was 4.2 volts.
I immediately set the BMS to "balance" the cells and it took while but it brought it down to the level of the others.

Ok so then I removed that cell from the rest of them and tried to charge up the rest of the seven cells left. Again after less than ten minutes the alarms went off and by the time I turned everything off there were two cells over charged at 4 volts and 4.1 volts.

I then balanced these as well and they went down.
And this is where I am now.
The other five cells appear to be fine though. I charged them up a bit [to 3.46 volts] and as they seemed to be fine I stopped it there.
This took an hour or so and no runaways at all of the five left over.

So the three cells that went nuts are now reduced to the level of the others by the balancer in my BMS.
But it is nuts how fast they went from 3.34 to 4 and over though.
It can't be stated enough at how fast the voltages move upwards when things go wrong.
So any newbies reading this. When you get warned by me or anyone else, listen. It goes up VERY fast.
I was lucky I had a BMS that warned me. Because even as I was turning off the charger etc it was going up still.
Like literally within seconds it went from the alarm going off at 3.65 to 4 volts.
Just like that, bam.
Crazy for sure.

Ok so how to help?
Unsure at this moment. Amy is looking into things so we will see how it goes.

Once more for newbies though. GET a BMS and use it. If mine had not warned me then the vent would have popped and my place would be filled with lithium powder etc. Not pleasant at all.