Harvested Samsung 25R from Ego 56V Battery Pack - Quick Question

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stayintheshadows
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Harvested Samsung 25R from Ego 56V Battery Pack - Quick Question

I had a failed Ego 56V battery pack laying around for the last few months and finally got the courage up to try and harvest the cells from it. After ordering the appropriate security torx bit set, I was able to take it apart and confidently start cutting wires after watching a few youtube videos.

I was able to get 12 x Samsung 25R cells that all tested at 3.32V.

I had a single cell that tested at 3.32V as well but when removing the bottom tab on the negative terminal that had been spot welded on, I pulled a hole in the thin bottom metal of the cell. I swear I heard a brief vacuum or hiss sound, but after leaving it sit for an hour it seemed fine. Should I save this or just toss it?




I also had a single cell that reads 0V. I imagine this is why the pack was failed, but is there anything I should try to recover it? Anything I should do before I throw it out?

Edited by: stayintheshadows on 06/12/2021 - 23:46
texas shooter
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That cell and the pierced one is not worth trying to save. I try to drain the batteries to 0V before I toss them. For that I use an old Xenon bulb flashlight.

sarge12
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Definitely toss both!!!

kennybobby
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There appears to be something held between the wrappers—what was under the outer bright green wrapper?

The weld hole vented the cell and it should be slowly drained (.1C) and disposed.

The 0 volt cell could be drained or the internal protection device opened, it is likely not worth salvage efforts and could be dangerous if charging were attempted.

Now i used to think that i was cool,
drivin' around on fossil fuel,
until i saw what i was doin',
was drivin' down the road to ruin. --JT

stayintheshadows
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kennybobby wrote:
There appears to be something held between the wrappers—what was under the outer bright green wrapper?

The weld hole vented the cell and it should be slowly drained (.1C) and disposed.

The 0 volt cell could be drained or the internal protection device opened, it is likely not worth salvage efforts and could be dangerous if charging were attempted.

Yeah I think you are right on the venting. I think I heard a hiss but the TV was on in the background so wasn’t sure.

Between the bright green wrapper and the cell wrapper was a very brittle black wrap that slid off the cells. Example in this video: https://youtu.be/g-gwzmuQo98?t=74

I’m trying to charge the others today at 0.25a and will monitor temps closely.

Correllux
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Definitely recycle both of them.  I've done that before where I tugged on the tabs and ripped the can...don't recall any venting from mistakes on that end of the cell but I suppose it's possible.  It's usually such a fast quiet poof that it can be easy to miss it I guess.  Now when I do pack harvesting I use smooth jawed duck bill pliers and after snipping the tabs/wires to convenient lengths, I grasp them and roll the pliers sideways kind of like opening an ancient can of sardines or rolling up a carpet.  That works great, just be careful not to damage the cell wrap (if you do and it's too ugly, it's easy and cheap to rewrap them).  I use a small 3/8" flat bottom cylindrical grinding stone in a Dremel to smooth the nubs - does a great job as long as you are careful and remove only what's necessary...try not to damage the nickel coating and definitely don't dig in or gouge the can because they are thin. 

If you happened to create any sparks while you were separating cells, mark those and set them aside for closer observation even if their voltage still seems ok. 

After a slow full charge like you're doing now, test the voltage, let them rest for several hours and test it again, then let them sit unused and check again a few days, a week, in a couple weeks or a month.  The idea is just to determine that they are still healthy cells and do not self discharge.  Since they are used and were in a high drain/high heat application it's ok if they lose a tenth of a volt or so in a short period but they should stabilize and remain at whatever voltage point that is without draining further.  If your charger can show internal resistance (accurate or not) take note of that for each cell and monitor that over time/cycles for another idea of their health and remaining lifespan.

These from Tekton are excellent and inexpensive pliers for this...comes in smooth or serrated and they are well made, much better than the cheapies and better than Irwin, Gearwrench, etc.  I rounded the corners on mine for easier rolling/peeling, but you can find some long-nose pliers with decent parallel jaw surfaces that are fine, too.  He's got a little pair in the video you showed but those are a bit small/short for my preferences doing this.   https://www.amazon.com/TEKTON-Mini-Pliers-Smooth-PMN23001/dp/B07CQ4M211

stayintheshadows
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Correllux wrote:

Definitely recycle both of them.  I’ve done that before where I tugged on the tabs and ripped the can…don’t recall any venting from mistakes on that end of the cell but I suppose it’s possible.  It’s usually such a fast quiet poof that it can be easy to miss it I guess.  Now when I do pack harvesting I use smooth jawed duck bill pliers and after snipping the tabs/wires to convenient lengths, I grasp them and roll the pliers sideways kind of like opening an ancient can of sardines or rolling up a carpet.  That works great, just be careful not to damage the cell wrap (if you do and it’s too ugly, it’s easy and cheap to rewrap them).  I use a small 3/8” flat bottom cylindrical grinding stone in a Dremel to smooth the nubs – does a great job as long as you are careful and remove only what’s necessary…try not to damage the nickel coating and definitely don’t dig in or gouge the can because they are thin. 

If you happened to create any sparks while you were separating cells, mark those and set them aside for closer observation even if their voltage still seems ok. 

After a slow full charge like you’re doing now, test the voltage, let them rest for several hours and test it again, then let them sit unused and check again a few days, a week, in a couple weeks or a month.  The idea is just to determine that they are still healthy cells and do not self discharge.  Since they are used and were in a high drain/high heat application it’s ok if they lose a tenth of a volt or so in a short period but they should stabilize and remain at whatever voltage point that is without draining further.  If your charger can show internal resistance (accurate or not) take note of that for each cell and monitor that over time/cycles for another idea of their health and remaining lifespan.

These from Tekton are excellent and inexpensive pliers for this…comes in smooth or serrated and they are well made, much better than the cheapies and better than Irwin, Gearwrench, etc.  I rounded the corners on mine for easier rolling/peeling, but you can find some long-nose pliers with decent parallel jaw surfaces that are fine, too.  He’s got a little pair in the video you showed but those are a bit small/short for my preferences doing this.   https://www.amazon.com/TEKTON-Mini-Pliers-Smooth-PMN23001/dp/B07CQ4M211

Wow, thanks for the detailed response! I will take your advice on monitoring and testing the cells. I just ordered a few chargers that will test the internal resistance so will do that as well. Might even do capacity testing. I really only used the Ego battery probably 5 times before getting a warranty replacement and then it just sat there for nearly a year before I got enough courage to tear into it.

I was actually peeling the welded connector on the cell that I damaged and found gripping with pliers and twisting to be more effective. Thanks for the recommendation on the pliers.

stayintheshadows
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What are acceptable ranges for internal resistance? And is it normal for it to change as I am charging it?

Correllux
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stayintheshadows wrote:
What are acceptable ranges for internal resistance? And is it normal for it to change as I am charging it?


Here's a fantastic site/resource for that kind of thing and especially for identifying cells/specs when you dig into battery packs.  This is the page for the green 25R (there was also a light blue one apparently) and it has a .pdf link to the Samsung official whitepaper.  Says it should be around 22 milliohms in the 1-10 amp zone.  That's when new, and it could range more or less.  With cycling and aging/heat resistance usually goes up slightly or moderately after awhile...the cells may still deal with high current just fine but will reduce in capacity and throw off more heat when you put the beans to 'em. 

https://secondlifestorage.com/index.php?threads/samsung-inr18650-25r-cell-specifications.1738/ (they have a main database page where you can scroll through alllllllll the cells or filter by various parameters to narrow down a search.  It's great.)

All that said, the resistance rating is given for tests done with specialized and very accurate lab equipment under certain test conditions.  Our battery chargers are nowhere near this level.  Some chargers are better than others, some will change the value shown every time or when the same cell is put into a different slot, and some are so far off as to make the feature worthless.  Best you can do is keep all of the contacts clean (charger and cell both) and ensure there is good firm contact with the cell once inserted.  Sometimes on my chargers the resistance will read high (like stupid high even on new good cells) and then come down to a normal level after a bit of charging time...but often when I see that happen I can pull it, reinsert it and give it a twirl, and it reads normally (and often lower...to where it should).  Disadvantage there is smarter charges will see that high resistance reading and just provide a very low charge rate (safety...so as not to overheat) and then increase the rate if it sees the resistance drop later.  If you know the cell is in good shape you can override that smartness and just give it a manual charge rate.  To read your cells' resistance accurately you need to buy a specialized tester or a bench supply and hook things up correctly.  But as long as you can see that it's still low-ish and within or close to its range, all is good.  Even though your cells sound like they're pretty close to new, don't be surprised if your charger says things like 50 or 80 or 150 for resistance...just how most chargers are.
stayintheshadows
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Correllux wrote:

stayintheshadows wrote:
What are acceptable ranges for internal resistance? And is it normal for it to change as I am charging it?


Here’s a fantastic site/resource for that kind of thing and especially for identifying cells/specs when you dig into battery packs.  This is the page for the green 25R (there was also a light blue one apparently) and it has a .pdf link to the Samsung official whitepaper.  Says it should be around 22 milliohms in the 1-10 amp zone.  That’s when new, and it could range more or less.  With cycling and aging/heat resistance usually goes up slightly or moderately after awhile…the cells may still deal with high current just fine but will reduce in capacity and throw off more heat when you put the beans to ‘em. 

https://secondlifestorage.com/index.php?threads/samsung-inr18650-25r-cell-specifications.1738/ (they have a main database page where you can scroll through alllllllll the cells or filter by various parameters to narrow down a search.  It’s great.)

All that said, the resistance rating is given for tests done with specialized and very accurate lab equipment under certain test conditions.  Our battery chargers are nowhere near this level.  Some chargers are better than others, some will change the value shown every time or when the same cell is put into a different slot, and some are so far off as to make the feature worthless.  Best you can do is keep all of the contacts clean (charger and cell both) and ensure there is good firm contact with the cell once inserted.  Sometimes on my chargers the resistance will read high (like stupid high even on new good cells) and then come down to a normal level after a bit of charging time…but often when I see that happen I can pull it, reinsert it and give it a twirl, and it reads normally (and often lower…to where it should).  Disadvantage there is smarter charges will see that high resistance reading and just provide a very low charge rate (safety…so as not to overheat) and then increase the rate if it sees the resistance drop later.  If you know the cell is in good shape you can override that smartness and just give it a manual charge rate.  To read your cells’ resistance accurately you need to buy a specialized tester or a bench supply and hook things up correctly.  But as long as you can see that it’s still low-ish and within or close to its range, all is good.  Even though your cells sound like they’re pretty close to new, don’t be surprised if your charger says things like 50 or 80 or 150 for resistance…just how most chargers are.

Awesome info! Thanks again.

Yeah most are between 50-100mO on my new MiBoxer C4 and they vary during the charge cycle. Of the 12 good cells I kept, they appear to all be holding a charge similarly and the resistance is similar. I will capacity test a few as well as a check for capacity and temperature at a few discharge rates. The new charger is fun!

Thanks again for the help here.

Correllux
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You're welcome!  That's a good score of cells.  I've got a Dyson vacuum pack to dig into soon and I'm curious to see what's inside that one.  They are a royal pita to open up and then to get a couple of the cells out of the carrier but sometimes they use great cells like Sony or something.  Sometimes they have had cheap Chinese cells in them, though....for a $125 pack with six cells. 

stayintheshadows
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Dang! The capacity test on the MiBoxer C4 takes like 4-5 hours! I have completed 2 of the 12 batteries and they are both under 2200mah. Not terrible and definitely great for my use.

Just got my Xtar VC8 as well so will do a quick grading on the same cells to calibrate between the two chargers.

neo71665
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Toss it.

My old lady works as a computer tech at a school and she brings me home all the chromebook battery packs. I have a ton of samsung 30qs. Honestly to the point I been thinking about selling some on here, I have like 300 cells.

snakebite
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keep in mind the rated capacity is often to 2.5v or sometimes lower.
if your cutoff is 3v you could be leaving behind a bit of capacity.
its a good score!
and Neo which chromebook packs have 30q?
i doubt a low powered unit like a chromebook needs 30q.
maybe 30b?
are they pink or light purple?

neo71665
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Think they are hp chromebooks.

They have a pink wrapper and say:
Inr18650-30q
Samsung sdi
136

Ya tell me. Ill take picks of the battery packs and some cells if ya want.

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30q are popular for flashlights.
thats a great score!
i just got a bunch of laptop packs from a school that replaces every year.
gotta watch for those.