Self-Discharge UPDATE On 30Q 141 Cells

[eMark]

They show different grades of self discharge. Some are down by almost 0.15V after 3 days. They now have been discharged to 2.8V.
Will monitor for some more days, then do a discharge to 2.5V and see if this makes any difference.

For a self-discharge test you need to recharge a cell to resting 3.60V (or your preferred pack storage voltage) then record amount of discharge voltage after 3, 5 and ten days to get a better idea of degree of "regenerating".

FWIW, goatman's "regenerating" tests by first discharging to 2.5V were based on my previous 30Q experimental tests discharging to 2.5V. Then i charged cell(s) to at least 3.60V resting voltage before measuring amount of declining cell self-discharge voltage after 5 days and then voltage again at 10 days. From my rather extensive testing there was a noticeable improvement, but it was short lived. More "regenerative" testing needs to be done so your testing is appreciated.

FWIW, cells that are down by 0.15V or 0.10V(100mV) after only 3 days are **poor** candidates for "regenerating", but your testing may prove helpful / hopeful :thumb:

 

[izeman]

For a self-discharge test you need to recharge a cell to resting 3.60V (or your preferred pack storage voltage) then record amount of discharge voltage after 3, 5 and ten days to get a better idea of degree of "regenerating".

Somehow true. Sure, fully charged cells loose voltage quicker. But I have 6 cells to compare. 5 broken ones, and 1 known good one. And that one holds voltage very well, whereas the bad ones have lost A LOT of voltage already. So the result is easier to see as discharges happens quicker.

 

[eMark]

I have 6 cells to compare. 5 broken ones, and 1 known good one. And that one holds voltage very well, whereas the bad ones have lost A LOT of voltage already. So the result is easier to see as discharges happens quicker.

Also agree with your post on another thread as do more than a few others. One ES member even referring to 30Q as "junk"

Then let's take another genuine Samsung 30Q, the pink ones. ... I HATE THAT CELL. Would I have known before I wouldn't have bought it, and maybe go for the LG H2 or even the old 25R cell. Just my 2c

Lunacycle birthed their 30Q "naked" Wolf Pack in March 2018 ... https://electricbike-blog.com/2018/03/31/its-time-to-howl-baby-the-lunacycle-30q-wolf-pack-50-amps-continuous-at-52v-12ah/ There's been no customer feedback on this "naked" 30Q 52V 12Ah Wolf Pack since December 2018 ... What does that say about 30Q whether 136, 138 or the 141 cells? Now we're suppose to believe that the latest Samsung 30Q6 150 ___T cells Made In China are no longer plaqued by **unacceptable** self-discharge as soon as 40-50 c/d cycles ?

Darren2018's previous contribution to this thread is worth mentioning again. For those that may decide to purchase the new 30Q 150 ___T cells made in China. The first thing to do is pre-test them. See if any have already declined by more than -0.007V (Darren2018 method) from what is the shipped/received voltage of the majority of the cells (e.g. 3.400V). Then set aside those cells suspect as inferior in quality. Plan on ordering a few more 30Q6T cells than you'll need for your pack -- just in case some don't pass your pre-test criteria.

 

[goatman]

give it a try :lol: :lol: :lol:

 

[eMark]

There isn't the slightest indication of any marring blemish on metal can of adjacent cells to either of the two cells with can burn thru. Space between bare metal cans is 9/64". Both cells with severe can burn thru are in same series string of 5S3P Sub-Pack 2 (1S1P and 4S1P). Me thinks after nearly 250 c/d cycles they couldn't endure the "Raw Performance" ... :lol: :lol: :lol:

Something odd did happen in November that I'd never seen before over the accumulated 3,745 miles since 9/2019. Had charged the pack to 41.0V and just started triking with 5 bars showing on readout at full throttle. Hadn't triked more than 3/4 mile in 5th speed with 5 bars showing when all of a suddent it dropped to 3 bars and stayed that way until i stopped, scratched my head and fiddled around. Then triking again and it went back to 4 bars. That was probably when the can burn thru occured. Continued triking 3-4 more miles in 3rd and 4th speed while running a couple errands and returning home. Also the temperature was about 45 F so maybe that had some cause and affect.

Cycle charged and discharged the pack again and remember the same thing happened again dropping from 5 bars to 3 bars and then settling in at 4 bars after stopping, scratching my head and fiddling around. Charged and discharged the pack a couple times after that without any problem, but kept speed to 3rd and 4th "Casual Cruising" instead of 5th at full throttle.

FWIW the culprit wasn't a metal fragment that found its way into the pack shorting those two cells. Two of the twenty-one 30Q 141 cells with 245 c/d cycles apparently overheated causing burn thru. The only way to know for sure is to see if 30Q 141 can burn thru happens again in 2022 ... between 250 c/d cycles to 375 c/d cycles (likely closer to 250 than 375 ) ...

 

[eMark]

The reason for this lengthy end of the year summary on my experimental Vruzend 10s3p pack is that it may not last for another 125 cycles in 2022 … so the following boring data is more a record for me. There’s a possibility goatman and i may be running some comparative 30Q tests this winter on our used 30Q battery packs (17s4p & 10s3p). So this may scare him off if he really isn't interested in sharing the condition of the 68 used 30Q cells in his 17s4p pack ..... Work In Progress

After 125 c/d cycles in 2020 on my 10s3p experimental Vruzend Pack of 30Q “141” cells remarkably 20 of the cells had less than 0.01V (estimate -0.006V) of self-discharge after 44 days. However, after just 15 days 10 of the other 30 “141” cells had self-discharge estimated to range from -0.007V to -0.030V (storage voltage of 3.75V-3.74V). At that time my DVM only read 2 decimal places instead of my current DVM (0.000v) to 3 decimal places … https://www.amazon.com/gp/product/B07TWQ4ZSJ/ref=ppx_yo_dt_b_asin_image_o03_s00?ie=UTF8&psc=1 ... just what i needed thanks to Darren2018

On 12/20 discovered that 9 of these 30 “141” cells suffered from **unacceptable** self-discharge. Replaced them with 9 new 30Q6 cells i had just received from IMR for under $5 each. One of the 30 “141” cells had a self-discharge of only -0.002V after 15 days. Decided to use it as one of the 10 30Q6 cells i had just received from IMR was defective (tiny can puncture). Never noticed it until after removing the pink label wrap. All 10 of the 30Q6 "KH1T" were same maufacturing code numbers on metal can. So far after 125 cycles in 2021, the Delta OCV is **acceptable** 10 days later (12/3 - 12/13) after 3 days resting (11/30-12/2)

Had decided to remove all of the pink label wraps to see whether the 30 “141” cells were from just one manufacturing run or several runs (five different runs). By removing the pink label wraps it was easier to attach the Vruzend end caps. The caps really didn’t need to fit so tight now that barrel bolts come with the V2.1 kit to secure contact of the cells with the Vruzend end caps.

Because my Balance Charger is only 2S-6S i had to make two 5S3P Sub-Packs using two Y-cables. One with Deans connectors for bulk charging and the other Y-cable for voltage readouts via the JST-XH 5S balance leads to HTRC Balance Charger … https://www.amazon.com/Charger-Discharger-Balance-Battery-Chargers/dp/B07P3ZRTMY/ref=asc_df_B07P3ZRTMY/?tag=hyprod-20&linkCode=df0&hvadid=242048352875&hvpos=&hvnetw=g&hvrand=9121006707778072797&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9019693&hvtargid=pla-733934611197&psc=1

On 11/23/21 the Vruzend experimental 30Q 10S3Ppack was charged to 40V and rested for 12 hrs. On 11/24/21 all of the bus bars were removed to check individual cell voltages. Six of the previously good “141” cells having enduring another 125 c/d cycles in 2021 (250 total) were found to now have **unacceptable** self-discharge when tested on 11/24 ... ranging from -0.014V to -0.175V. As i disassembled the Vruzend p-groups from each other it was only then that i noticed the two “141” cells with can burn thru ... https://endless-sphere.com/forums/download/file.php?id=307395

The worst one declined by -0.005V in 12 hrs and -0.175V after 5 days (11/29). The self-discharge of the other "141" cell with can burn thru was at 3.984V when tested on 11/24 about same as other cells. However within 1 day its voltage had declined from 3.984V to 3.967V and by 11/29 declined to 3.935V (-0.049V in 5 days).

Those two with can burn thru plus 4 additional “141” cells suffered from **unacceptable** self-discharge when tested on 11/24/21 and were replaced with six other “141” cells from my original order of 40 in November 2019. They had been in storage since 11/2019. The two 5S3P Sub-Packs (now having acceptable cells) were reassembled with bus bars, Deans connectors and JST-XH 5S balance leads. Then as a 30Q 10S3P pack once again it was painstakingly discharged until bounce back resting voltage was fairly stabilized at my target of 36.6V by the afternoon of 12/3/21.

Once again all the bus bars were removed to record individual p-group cell voltages. All 30 cells (21 “141” & 9 “6 KH1T”) were within 0.002V of each other ranging from 3.662V to 3.660V. After ten days (12/3 - 12/13) four of the six “141” cells (that had been in storage since 11/19) showed **unacceptable** self-discharge after just ten days ranging from -0.003V to -0.007V. However, i've decided to use them anyway and disassemble this 10S3P 30Q experimental pack after the first 50-75 c/d cycles in 2022 ... instead of waiting until 12/22 and another 125 more cycles.

PS (couldn't resist): More than several years as an aspiring photographer i applied in writing (didn't have internet) to be chosen as one of twelve finalists for a Photo Safari. The one deciding at least ten to be chosen replied back by first saying: "Finally someone who can write a complete sentence" ... at the time i took it as a compliment, but looking back now maybe not :wink:

Balancing p-groups within 2mV of one another. Found such tinkering to be overkill, but still a wothwhile learning experience :thumb:

16awg solid copper run to front to see amp draw at different speeds and inclines using my old trusty Lipo AstroFlight Watt Meter :thumb:

 

[TysonScott]

I bought some 30q cells from BH in overstock packs and reclaimed the cells. How would I know if they were self discharging? the packs have all been within .03v besides one whole pack that was dead out of the 40 I ordered. They have been sitting for about 3 months as I work on other aspects of my build, would this be enough time to know if they are self discharging?

 

[docw009]

I bought some 30q cells from BH in overstock packs and reclaimed the cells. How would I know if they were self discharging? the packs have all been within .03v besides one whole pack that was dead out of the 40 I ordered. They have been sitting for about 3 months as I work on other aspects of my build, would this be enough time to know if they are self discharging?

I bought ten of these from Battery Hookup, which gave me 60 cells, all but one testing out at 3.1AH, the exception being 2.8AH which I discarded, The code on them is "136" so they may from 2019 too. IR, by the way is 12-13 milliohms.

I have not run them on an ebike yet, having just built them into a 13S-4P battery 10 weeks ago.



This is the first time I have seen this thread. I believe Emark uses the Vruzend system, which is cell holders, contacts, and pressure. This allows him to inspect the individual voltages on a P-group when he removes the bus. He finds some of the individual cells at lower voltages. Those of us who use spot welds or other semi-permanent connections cannot do this.

My experience with 30A cells in Luna packs has been OK. I own three from 2015-2017. All have had light use, less than 100 partial discharge cycles. I hardly ever take them flat unless I am doing a test of capacity. Using the methodology where I ran them til the bike shut off sround 40V (3.1V/cell) and then recharged with a cheap wattmeter to measure the AH. , All were still above 80% of their original 3AH/cell capacity/ I have other tests, that suggest they're better than that, but I'll leave it.

I have yet to ride with the Battery Hookup cells. Guess I better start,

 

[goatman]

i think in my signature you can see my tests on desulfating 30Q packs. i crashed my trike about a year and half ago and the other day i grabbed a 30q pack thats been just sitting the whole time and its still fully charged, it didnt self discharge

 

[batteryGOLD]

i think in my signature you can see my tests on desulfating 30Q packs. i crashed my trike about a year and half ago and the other day i grabbed a 30q pack thats been just sitting the whole time and its still fully charged, it didnt self discharge

Sir, desulfating? do U mean lead acid battery charging technique of pulses? charges up to 4C and discharge 1C pulses ,1k times per second. reflex tech?
I think that chargin tech does not work at lithium cells.. I tested reflex pulsed chargin at lithium 18650 cells, and seems to be wasted time

anyway I have also a bunch of 30Q used cells from a 10kw ebike.
arround 200cells 30Q. I grouped it with adesive tape at each 10P from 20S battery
all cells 200cells stored at 4,1V 90% SOC charge, for a long period of time 5months
now I checked all cells voltages, and some keep aprox 4,1V and other are leaking voltage, some down to 3,8V, 3,5V ,3,0V and some zero volts

the percentage of faulty 30Q cells is 30%, means from 200 , I salvaged 140, and sent other 60 faulty cells to tha lithium yellow trash can..
140 of 200 cells, keep same voltage 4,1 since 5months ago, soo seem to be maybe ok cells

30Q new/used are tricky. all tend to leak voltage at some point in time. even a new 30Q used 1month, could start having tha "voltage leak desease"
tha engineers that designed 30Q did some mistake that leads to leaking issue over time. all 30Q are exposed to this leak issue any point in time!

Wish U luck when using 30Q at a new battery build, or stay away from those..
go to sony VTC6 3000mAh 30A made in japan.. just sayin..

 

[batteryGOLD]

I bought ten of these from Battery Hookup, which gave me 60 cells, all but one testing out at 3.1AH, the exception being 2.8AH which I discarded, The code on them is "136" so they may from 2019 too. IR, by the way is 12-13 milliohms.

I have not run them on an ebike yet, having just built them into a 13S-4P battery 10 weeks ago.

U got genuine 30Q cells, they do not leak any voltage and nice IR
soo consider Battery Hookup a USA trusted cells supplier.

 

[goatman]

Sir, desulfating? do U mean lead acid battery charging technique of pulses? charges up to 4C and discharge 1C pulses ,1k times per second. reflex tech?
I think that chargin tech does not work at lithium cells.. I tested reflex pulsed chargin at lithium 18650 cells, and seems to be wasted time

anyway I have also a bunch of 30Q used cells from a 10kw ebike.
arround 200cells 30Q. I grouped it with adesive tape at each 10P from 20S battery
all cells 200cells stored at 4,1V 90% SOC charge, for a long period of time 5months
now I checked all cells voltages, and some keep aprox 4,1V and other are leaking voltage, some down to 3,8V, 3,5V ,3,0V and some zero volts

the percentage of faulty 30Q cells is 30%, means from 200 , I salvaged 140, and sent other 60 faulty cells to tha lithium yellow trash can..
140 of 200 cells, keep same voltage 4,1 since 5months ago, soo seem to be maybe ok cells

30Q new/used are tricky. all tend to leak voltage at some point in time. even a new 30Q used 1month, could start having tha "voltage leak desease"
tha engineers that designed 30Q did some mistake that leads to leaking issue over time. all 30Q are exposed to this leak issue any point in time!

Wish U luck when using 30Q at a new battery build, or stay away from those..
go to sony VTC6 3000mAh 30A made in japan.. just sayin..

i just used desulfate (lead) as a description of what i was seeing in my testing(lithium), i still use it because that thread is full of the word desulfate.
regenerating is a better description

 

[eMark]

I bought some 30q cells from BH in overstock packs and reclaimed the cells. How would I know if they were self discharging? the packs have all been within .03v besides one whole pack that was dead out of the 40 I ordered. They have been sitting for about 3 months as I work on other aspects of my build, would this be enough time to know if they are self discharging?

You can pretest by charging to say 4.0V resting volts. Then store in safe place and check voltages with DMM that reads to 3 decimal places (mV) after 2 weeks. Any with high self-discharge as much as 8-12mV after 2 weeks are suspect. Normally if you recharge a pack every few days your reclaimed pretested cells should be OK for many cycles . Periodically check voltages of each of your parallel groups and [if possible] bottom balance your p-groups as needed before charging.

Degree of higher than normal self-discharge wasn't a problem until 125 c/d cycles. 9 out of the 30 cells (10s3p) were removed and replaced with newer 30Q "6 T" cells. After another 80 cycles no problem with the newer 9 30Q "6 T" cells, but 3 more of the "141" cells suffered from high self-discharge and needed to be replaced.

My 10s3p now has 3 different 10s strings. One of the 10s strings is with 10 30Q "141" cells with 300+ cycles. Another of the 10s strings is with 9 30Q "6 T" cells and 1 "141" cell (225+ c/d cycles). The other 10s string is with 10 new 30Q "6 150 T" cells with only 6 c/d cycles so far into 2023. Always bottom balance (when necessary) my 10 p-groups before charging the 10s3p Vruzend experimental 30Q pack to 41.0V.

Each winter disassemble 10s3p pack. test each cell, remove cells suffering from high self-discharge and replace with good cells. 10 30Q "6 150 T" cells in February of this year. 6 of the removed "141" cells are still good that were replaced in the 10s string for 2023 with the 10 30Q "6 150 T" cells