Battery Failed.

[docw009]

Had a battery fail yesterday. A mix of new no name and branded cells in a 13S-3P shrink wrapped pack I made in 2022. Never used and was stored at 30% til yesterday. Short story...I charged it up and it seemed unusually warm. Opened it up and found a hot cell group. Pulled them out immediately and threw them in a tub of ice water.

This morning, the three cells are ,5, 2.2 and 3.1 volts, The first one might have developed an internal short and pulled the whole group down. This could have been another battery fire while charging scenario, That's it. No more unknown brand cells.








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[Chalo]

A more rewarding lesson would be "1P is best P".

 

[harrisonpatm]

A more rewarding lesson would be "1P is best P".

More specifically:

A mix of new no name and branded cells

If you're going to use multiple P, then you'd better put in the effort to match them

 

[n00b]

Had a battery fail yesterday. A mix of new no name and branded cells in a 13S-3P shrink wrapped pack I made in 2022. Never used and was stored at 30% til yesterday. Short story...I charged it up and it seemed unusually warm. Opened it up and found a hot cell group. Pulled them out immediately and threw them in a tub of ice water.

This morning, the three cells are ,5, 2.2 and 3.1 volts, The first one might have developed an internal short and pulled the whole group down. This could have been another battery fire while charging scenario, That's it. No more unknown brand cells.








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You threw lithium cells into water?
Why?

 

[fill]

OUCH.. bet its the last time you mix cells in a battery build.. better to fail on the supervised bench than 10 miles deep into a solitary wander trek.

 

[j bjork]

You threw lithium cells into water?
Why?

To cool them down, avoid thermal runaway and fire.

 

[BlueSwordM]

You threw lithium cells into water?
Why?

Willing to bet it was at the start of a thermal runaway.

Remove heat, and the thermal runaway will start.
Water works very well at dealing with lithium-ion adverse reactions, unlike with lithium primaries which use elemental lithium.

 

[docw009]

Wish I had more to add on this. The no name cells came out of an Aleuvy branded battery from Aliexoress. One of the cells started to warm up after coming out of the ice bath, so something was still cooking internally. I discharged the remaing Aleuvy cells to zero and got rid of them. One of that group also got noticeably warm during discharge while the others renained cool, Maybe they were always suspect.




















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[eMark]

Had a battery fail yesterday. A mix of new no name and branded cells in a 13S-3P shrink wrapped pack I made in 2022. Never used and was stored at 30% til yesterday. Short story...I charged it up and it seemed unusually warm. Opened it up and found a hot cell group. Pulled them out immediately and threw them in a tub of ice water.

IF happening in winter you could've just tossed it in a snow bank. That's what i did 5 years ago when a newbie. Now after reading your post i will know better than to be so asleep that it couldn't happen again.

Assuming ??? ... you purposely went ahead with this DIY experiment as a possible DIY of what NOT TO DO knowing doing so can be risky monkey business (letting sit for 2 years without ever charging/discharging, etc or periodically checking) which may have been your ?controlled? experiment.

Sometimes when we've been wise and lucky for years (battery DIY builds) we can kid ourselves. (thinking we've seldom if never-ever been so unfortunate (stupid) as to cause serious damage).

So what have you learned (that you can pass on to newbies) that you would've done differently if you had it to do all over again. Maybe a list of at least 1-5 of: "What I Should Have Done"

 

[neptronix]

I would also cycle test your cells & match them before assembling a pack.. i used to do this with RC Lipo.. and the packs i assembled out of lipo bricks lasted almost a decade w/o issue.

Such packs very rarely need balancing, i'd do it once every 100 cycles, but they didn't really need it. They naturally stayed in balance very well.

 

[eMark]

I would also cycle test your cells & match them before assembling a pack.

Getting to know docW009's knowledge / expertise since 2019, suspect it was a case of haste makes waste and/or too many projects in the works. Find it hard to believe that he hadn't checked (balanced if necessary) the cells before assembly. Also arranged the cells in each of the 3p groups with same number (if possible) of Aleuvy cells (2) and "branded cells" (1) or vice versa (1) & (2) in each of the 13 3p groups. Apparently there were too many irons in the fire to periodically check every 2-3 months instead of letting it rest for 2 years at only 30% charge. Some recommend at least 50% charge and if possible even checking each p-group (with a DIY build) every month when in long term storage (2 years).

This morning, the three cells are ,5, 2.2 and 3.1 volts, The first one might have developed an internal short and pulled the whole group down. This could have been another battery fire while charging scenario, That's it. No more unknown brand cells.

Wouldn't the first one (5v name brand cell?) be over-charged by 0.8v from FULL charge of 4.2v? Even with BMS over-protection the combined voltage of that 3p group would still be below 4.2v at 5v+2.2v+3.1v=10.3v/3 = only 3.43v.

Were both the 2.2v and 3.1v cell "no brand" Aleuvy cells? The chance of a fire/explosion with a cell charged to 5v is possibly greater with cheap no brand Chinese cells than popular A-grade brand name cells. Was the 5v cell a name brand A-grade cell?

 

[leffex]

Had a battery fail yesterday. A mix of new no name and branded cells in a 13S-3P shrink wrapped pack I made in 2022. Never used and was stored at 30% til yesterday. Short story...I charged it up and it seemed unusually warm. Opened it up and found a hot cell group. Pulled them out immediately and threw them in a tub of ice water.

This morning, the three cells are ,5, 2.2 and 3.1 volts, The first one might have developed an internal short and pulled the whole group down. This could have been another battery fire while charging scenario, That's it. No more unknown brand cells.








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Lucky you.

Don't do that again. But you already now that?

Keep safe!

There are hidden errors. You can even build a pack with branded cells and put a puncture on one of the cells through the nickel. Because of the tool you have might not be consistent enough or that you have overpowered the settings. This can be heard when building the battery or just develop some unknown time after storing or usage. Then it will act, usually pushing down voltage on one cell group. This happends so much more often with the cheapest cells and new packs have been build with these crappy cells for years already. Although it might not be a safety concern but the issue with capacity. However it may be of a concern if the batteries are altered and tampered or after being thrown away taken by a not so smart newbie.

 

[docw009]

An inexpensive Aleuvy 13S-2P, rarely used. Thought it would be more useful if I made it 3P. I did take it apart, and since it was glued, the cell wrappers were ruined extracting the cells, New wraps. A cell holder. Tested every Aleuvy cell for capacity and IR. New balance BMS. The works. Put a new Eve 25 cell, same capacity, alongside two Aleuvy cells, I still never used it.

I store my packs at 30%. One or two have dropped under LVC amd gone to sleep, but they were always able to recharge so the cells were close to 3V, This particular pack had gone to sleep, but it did recharge, but hadn't hit max when I went to shut off the charger, I saw it was warm, so I put my load tester on it to discharge it, I recall it was around 53V and then it shut off quickly. Another reason why I opened it.

 

[eMark]

Was expecting somebody to call me out for what i thought was my stupid interpretation ...

It's virtually impossible for 3 cells in a 3p group (when charged) to end up having as much voltage differences as: 5v, 2.2v, 3.1v. So, it seemed obvious these voltages were for three of the 3p groups: 1, 2, 3. The 1st group (5V) has the best cells after 2 years and the 2nd and 3rd 3p groups with good for nothing cells. Then i reread it again and in fact the 3 cells were in just one of the 3p groups. One of these 3 cells was charged to 5.0v with the orher two cells not able to take a charge above 3.1v (el'cheapo Aleuvy salvaged cells?). The good cell (A-grade brand name cell) being overcharged by 0.8v to 5.0v YIKES!

Even with a "Protection BMS" it wouldn't have prevented the good cell in the 3p group from being overcharged to 5.0v. Conclusion: Do not use cheap no name cells of questionable quality for a DIY build. Their low price is tempting, but don't fall for it. You could end up hurting yourself and others and possibly starting a house on fire.

What i yet don't understand is why he writes ... "The first one (5v) might have developed an internal short and pulled the whole group down." If anything the overcharged (5v) cell should have brought the other two cells up which suggests that those two cells (2.2v, 3.1v) are now good for nothing after 2 years. Aooarently after 2 years they had discharged most of their capacity and wouldn't take a charge above 3.1v.

 

[Gruesome]

Maybe ',5 ,' was supposed to read '.5,', short for '0.5V,'.