Look what I found in the recycle bin

250 posts / 0 new
Last post
derfyled
derfyled's picture
Offline
Last seen: 1 week 6 days ago
Joined: 04/16/2013 - 07:51
Posts: 48
Location: Canada

Hmm… seems like a good start ! Thanks Thumbs Up ! Now if I could find one with a double or even more USB output…

raynman
Offline
Last seen: 3 days 8 hours ago
Joined: 07/13/2016 - 21:00
Posts: 140
Location: Maine

…don’t know why you couldn’t wire multiples in parallel off the battery pack – muck up some kind of housing for it…

derfyled
derfyled's picture
Offline
Last seen: 1 week 6 days ago
Joined: 04/16/2013 - 07:51
Posts: 48
Location: Canada
dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut
derfyled wrote:
Back on the subject of the 40V Ryobi. Anyone knows a way to convert it as a USB power bank? That would become my dream camping power pack…. I know USBEAST sell some module to convert smaller batteries into a power bank but I have never came across such a device to use a 40V battery pack.

Great idea! I would like to see this done. The result would be a huge 26,000 mAh power bank.

Ridgid tools already makes one for their 18V tool battery packs. I found this in Home Depot on the clearance rack. It currently is priced at $18.00 and connects to an 18V pack. One of these and a 4Ah pack would be equal to a 20,000 mAh power bank.

I am waiting for a lower price.
The DEWALT-DCB090 is also available and costs around $30. Battery or charger not included

ImA4Wheelr
Offline
Last seen: 3 days 11 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7444
Location: SC

Speed4goal wrote:
Found a Toshiba laptop pack in Lowe's yesterday. Cells were just slightly below 2 volt. Sanyo ur18650fj 2200mah But didnt warm up at all charging and slightly warm on discharge. By the time 20mah was put in they were at 3.5 it looks like a pack someone never used. It was rated at 4300mah and all cells tested 2170 or better 4 of 6 over 2200. Will keep a eye on them for awhile. Cv stage wrnt quickly like new cells do. Input was roughly discharge capacity Found another no name brand pack at best buy. Only once cell had 1400mah but I use all the dead cells as a reason to go back to the best buy bin when I'm that way. I actually found last month 2 lg hg2 in the bin. On the case it had bad recycle on the case. One cell had a torn wrapper. Once cell tested 2800 the other 3000. There was 4 vtc5 in there with them. But they are pretty worn. Testing between 1600-1700. I use them while low wattage vaping around the house and my good batteries at work to last all day. Save some wear and tear on my expensive cells. Best find those was two perfectly like new hg2. Looks like they were recycled because of a torn wrapper. The free wraps from imr orders fixed that quickly. I see some people ask about what to say. When approached. Best buy has never approached me I usually have a battery wrapped up to drop in either alkaline or a bad 18650. I break up my bad ones for multi trips (reasons to dig in) If it isn't piled up near the top I shone my phone light down in there to get a peak if I see something I just snatch it and walk out and don't look back. I bring a bag with batteries there. So if they see me standing there a minute it looks like I'm dropping stuff off. I do the same at Lowes or home depot sometimes. But usually just walk in and start digging. If anyone says can I help you etc. I say my brother dropped off a couple of my packs for recycling but he brought the wrong ones he brought my good batteries not the dead ones. Usually not a problem. If I don't see something I'll still take a couple identical ones to use as another reason to stand around the bin at best buy or another store. Edit I will say its very addicting I've only been doing this for a few months compared to most of you. About 50/50 good cells to trash cells so far. But for free can't complain. If I get to use them for 6 months then recycle that's fine. Only get to go by best buy once a month and home depot. Lowes is in town and the only place around here I know of that does battery recycling. Maybe some other smaller stores do I'll have to see at some point

It is addictive.  I agree.  Tool packs are where it really is at as you will learn if you keep it up.  Nice suggestions on how to deal with snoopy employees.  Smile

derfyled
derfyled's picture
Offline
Last seen: 1 week 6 days ago
Joined: 04/16/2013 - 07:51
Posts: 48
Location: Canada

That seems like a very nice device. Since Ridgid and Ryobi are related, I hope Ryobi will soon make some for their batteries. I own the same lime green 40v powerpack you’ve found. I got it for 20$ with the charger, almost new, in a garage sale. I don’t own any tool for it but the USB monster power bank immediately crossed my mind.

dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut

What I found in the recycle bin today made me aware of something I never really thought about.
Whenever I go into a Home Depot I make it a point to try and look into the battery recycle bins by the returns desk. Today was no exception.
This time I actually had some loose 18650’s that I wanted to dispose of. When I came up to the bin I didn’t see the roll of plastic bags they keep there so that loose cells can be wrapped. I could see from looking inside the bin that there were some in there so I reached in and pulled one out. Thing was though it already contained some packaged cells!

Looking a little closer, I noticed this sticker on the outside of the bag.

After reading THAT, I knew just what I was going to find. New cells that had “gone to a penny” and where thrown away by Home Depot and placed into the recycle bin.

For those that don’t know, when Home Depot puts items on clearance they generally are reduced over a period of time to 75% off. If after a set amount of time, if those items still do not sell, they pull them from the shelves, mark them for a penny in their system, and throw them away
Lamp shades, plumbing parts, light bulbs etc get thrown into the dumpster and crushed. Batteries however have to be disposed of in the proper way.
They are thrown in the same battery recycle bin that is place by the returns desk for the general public.
I netted 7 packs of 4 cells each of these Energizer Advanced Lithium AAA cells. And they are not “damaged”, they are brand new.

Actually I have found quite a number of these cells in both AA and AAA at a penny, Here is a link to the “Home Depot Deal Alerts & Discussion Thread”
where I posted about my score.
http://budgetlightforum.com/comment/954776#comment-954776
and again here http://budgetlightforum.com/comment/993261#comment-993261

dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut

Found these 3 NiCd battery packs yesterday. they look like they were installed in a piece of equipment, and as such they are probably spent.

They are made up of 10 “D” cells each, rated at 5000mAh.

I tested one for voltage as it came out of the bin, 10.56V

As I said, they will probably be worn out. I am charging one now at 700mA. It will take hours before I know for sure their condition. At the very least, I scored 3 inline fuse holders Smile

snakebite
snakebite's picture
Offline
Last seen: 5 hours 34 min ago
Joined: 11/20/2013 - 20:21
Posts: 1615
Location: dayton oh

those are stairlift packs.
one of my clients gets new ones every 6 months.
i get the old ones to “recycle” and get paid for the service call.
they are always still over 5ah.
some have flattops some button tops.
free nicad d cells!
some packs i leave as is and power stuff with them.

dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut

That was good news to hear.
The first pack I took apart, the pack I suspected would be weak, yielded cells that tested at only around 2000 mAh.
The second pack, which included a physically damaged cell, did better, around 4800 mAh Smile
Very pleased with that kind of number. Those cells are much better than the old NiCad and NiMH “D” cells that I had been using.

Does anybody know where to get “D” cell shrink wrappers?

jf_smm
Offline
Last seen: 7 hours 5 min ago
Joined: 05/30/2016 - 12:29
Posts: 353
Location: NorCal

Haven’t used this guy but there are tons of sellers that sell heat shrink in sizes that should work for a D cell.
This example was for wrapping 4 18650’s together so I think it should work.

http://www.ebay.com/itm/New-66MM-42MM-PVC-Heat-Shrink-Tubing-Wrap-For-18...

I just happened to see this while looking for some specific colors to deal with overly glued cells from a laptop pull this weekend.

SMM

Lightbringer
Lightbringer's picture
Offline
Last seen: 1 hour 2 min ago
Joined: 08/30/2016 - 14:12
Posts: 2884
Location: nyc
jf_smm wrote:
Haven’t used this guy but there are tons of sellers that sell heat shrink in sizes that should work for a D cell.

And if not, look for shrinkwrap for a 32600 or 32650.

09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut

Thanks guys for pointing me in the right direction. Somehow I calculated that I would need 50mm pre-shrink tubing and did an internet search. I found a site that offered just that and placed an order.
It wasn’t until I was checking out that I realized I had stumbled upon none other than FastTech. Facepalm

BTW, the popular use for 50mm shrink tubing is for 2 – 18650’s side by side.

Jtm94
Offline
Last seen: 20 hours 50 min ago
Joined: 02/22/2017 - 05:08
Posts: 227
Location: Pennsylvania

This tube inspired me to take a stop by our local Best Buy, Home Depot, and Lowes in search of cells. So… Best Buy had not a thing that we cared about(I went with a friend I got into flashlights). It was filled to the brim with AAs and a little rummaging revealed a shoddy flat power bank so it was a bust…. Next was Home Depot, and after asking several employees we almost thought they didn’t even have a battery bin. It is marked online that they have a bin, but it isn’t a traditional one, but just a series of cardboard boxes filled with various drill battery packs.. I had a friend that worked there ask someone if we could just take them all and he said sure so we walked away with 2 boxes of assorted batteries. Lowes had the most conventional battery bin, probably because they had just built it. This time we hit the employees with an educational shtick that we were looking for cells in order to help with our educational robotics program and they said sure take whatever we have, SCORE. Sadly all they had were these Motorola NIMH packs, but as I suspected they each contain 6 NIMH AA sized cells.

Onto the haul:

Unfortunately only one of the drill packs was Li Ion and had 10 of these 18650s

They all registered at around .5 volts so pretty dead. From battlebots in high school we used A123 and other Lithium cells we would often have cells drop below the “safe” voltage and just force charge them until they hit the required voltage. I have managed to get 1 of the 18650s up to 4.2v, but they all seem to have this problem where they are constantly discharging so I expect either a protection has blown internally or maybe they have external circuitry to blame? The one cell I charged was the one that discharged the slowest, the rest would discharge at a rate near 0.01volt per second so I didn’t even fiddle with them. I’ll see if the one that I charged holds a usable charge over the course of a few days, otherwise it’s not really worth keeping around. I did not take any pictures of the NIMH AA cells, but they all seem usable I’ll try to charge a few and test if they hold onto it or can power stuff. I’m not well versed in NIMH do they have a voltage they shouldn’t drop under?

All in all, it was a great first time haul. Anyone have ideas for all the nicad cells I got? A lot of the 14v packs measured in at around 13.3volts and seemed healthy. I just didn’t tear into them because I was only really interested in the 18650s, which incidentally we got the least of.

edit: also got what looks like a brand new never used electric scooter lead-acid battery along with a very-used lead acid battery. We have plenty of fodder to give us an excuse to start frequenting the bins…

dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut

Jtm94 wrote:

Unfortunately only one of the drill packs was Li Ion and had 10 of these 18650s

They all registered at around .5 volts so pretty dead. From battlebots in high school we used A123 and other Lithium cells we would often have cells drop below the “safe” voltage and just force charge them until they hit the required voltage. I have managed to get 1 of the 18650s up to 4.2v, but they all seem to have this problem where they are constantly discharging …

With all the packs I have opened, I have NEVER come across one A123 cell that was any good. Their cells are not as good as the modern ones from Samsung, LG, or Sony.

Maybe you got away with charging up dead Li-ion cells in high school, but that is something you definitely should not do. There is too great a chance of a catastrophic failure. Look for batteries that are in the bin for reasons other than that they are worn out, or have been discharged to unsafe levels.

For instance, of the 3 NiCad packs I described above, one pack was discarded because it was simply worn out. The individual cells have lost over half of their storage capacity.
BUT, the second pack I described above was in the bin, I think, because just one of it’s cells failed early on, rendering the whole pack useless. After disassembling that pack and separating the cells, I have netted 9 good cells out of 10. Those 9 cells still function at near full capacity.

Bottom line is be fussy with what you pull out of the bin, most of it will be trash.
But there are some good finds, if you are willing to be patient. Wink

Jtm94
Offline
Last seen: 20 hours 50 min ago
Joined: 02/22/2017 - 05:08
Posts: 227
Location: Pennsylvania

Aw, that’s a shame. I’m not really worried about catastrophic failure, I took necessary precautions. I will put my safety above all else, I don’t take these things as lightly as I used to. The best part was that in high school we would solder tabs onto each of the cells, then over discharge them, force charge them as nicad, have them near punctured in battle, and continue using them. In all my years never have I seen a cell do anything dangerous. There was one time a 21volt lipo that was huge got short circuited and it didn’t have a protection board so it fused the wires together and started a fire. The cell got puffy after, but never vented. Just a few horror stories from high school and most were due to our instructor neglecting safety, I don’t take after those bad practices.

Home Depot was all or nothing, they made us take everything. A lot of the drill packs were just returns, but they don’t restock the packs if they’ve been used. I’m certain I have a lot of usable nicad cells, some of the packs have leaky cells and read flat so there’s no use fiddling. I’ll just return those to the bins. I get my chances are slim, but it’s all about the gamble right?

dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut

Jtm94 wrote:
Aw, that’s a shame. I’m not really worried about catastrophic failure, I took necessary precautions. I will put my safety above all else, I don’t take these things as lightly as I used to. The best part was that in high school we would solder tabs onto each of the cells, then over discharge them, force charge them as nicad, have them near punctured in battle, and continue using them. In all my years never have I seen a cell do anything dangerous. There was one time a 21volt lipo that was huge got short circuited and it didn’t have a protection board so it fused the wires together and started a fire. The cell got puffy after, but never vented. Just a few horror stories from high school and most were due to our instructor neglecting safety, I don’t take after those bad practices.

Home Depot was all or nothing, they made us take everything. A lot of the drill packs were just returns, but they don’t restock the packs if they’ve been used. I’m certain I have a lot of usable nicad cells, some of the packs have leaky cells and read flat so there’s no use fiddling. I’ll just return those to the bins. I get my chances are slim, but it’s all about the gamble right?

Let me make just one last point.
Say the probability of a new, perfectly good cell of venting and catching fire is 1 in 10 million, let’s just suppose that.
And let’s just suppose that discharging it all the way to 0 volts and then charging it back up increases the probability of a problem occuring by 10,000 times. There would still be a 1 in a 1000 chances of something going wrong. Just because nothing ever happened doesn’t mean the danger hasn’t increased.
Because of this, I strongly believe that it is very easy to become complacent and careless. For that reason, we must draw a line and say do not use after a certain discharge voltage is reached. I would recommend the numbers generally discussed in all the literature on this subject.
What you do is your own responsibility.
BTW, I store all of my scavenged battery packs outside in the shed, away from the house.
I am nervous about the new ones I buy as it is.

allcool
Offline
Last seen: 20 min 21 sec ago
Joined: 06/20/2016 - 10:30
Posts: 157
Location: Miami

dchomak wrote:
allcool wrote:
JACKPOT...!!!

Ego 56v tool pack, = 42cells, Samsung 25Q
Ryobi 40v tool pack, = 20 Samsung 13Q

...............................................

This is getting fun, thanks BLF for showing me the light, to the recycle bin...

Going to start to get picky on what I take from the bin. What tool packs have the best cells..?

Oh, by the way, 56v does pack a nice wake up shock, wear gloves, be careful with the ego...


WOW!!!!!!!!!!!!!!!!!!
I didn't even know that 7.5Ah EGO battery existed.

Would you mind posting your find in my thread? I started it when I first found a Ryobi 40V 2-1/2 years ago. At the time I thought THAT was unbelievable.
"Look what I found in the recycle bin":http://budgetlightforum.com/node/33344

 


You +definitely+ have found the best all time battery as far as I am concerned!
That battery can be ordered at Home Depot and costs a lot of money.
!{width:50%}[url=http://imgur.com/REx6lfn][img]http://i.imgur.com/REx6lfn.png[/img][/url]...

 

 

Don't mind at all,,, here ya go.

 

JACKPOT...!!!

Ego 56v tool pack, = 42cells, Samsung 25Q
Ryobi 40v tool pack, = 20 Samsung 13Q

Well, I've tried to get into the recycle bin at my local Home depot to no avail, for months now. Every time into it, a employee questioned me and more or less stopped me from any further exploration of their bin...
This all changed last week.

HD moved the recycle bin to a out of the way, kind of out of sight location. So,,, last week was my first bin pick. No more questions from employee's that now don't see me dropping off my recycles and exploring whats in their bin...

Got a couple tool packs last week out of HD recycle bin. No good. All the cells were 18650, LG1100mAh, but had 1.1v or less. Tossed them all in my recycle ammo box after a wrestling match with the packs disassembly.

Yesterday morning got lucky. Got a Ryobi with 20 Samsung 13Q, all cells 3.1-3.3 volt.

Now for the Ego, a massive tool pack, chock full of 18650, got to be the recycler's JACKPOT.. 42 Samsung 25Q all cells 3.2-3.4v. Yes, I know they aren't 30Q or Sanyo 3600mAh, but for free, not bad.
They seem to be hi drain cells. Power my highest amp lights as good as any of my best high quality batteries, says my trusty amp probe. And the ones I charged so far, charged up great, didn't even get warm in the lii-500, and took a full charge.

Getting good at taking these tool packs apart, a slight art to it. They sure don't make it easy.
Haven't got them all charged up yet, but dang, more cells then I know what to do with,,,lol

This is getting fun, thanks BLF for showing me the light, to the recycle bin...

Going to start to get picky on what I take from the bin. What tool packs have the best cells..?

Oh, by the way, 56v does pack a nice wake up shock, wear gloves, be careful with the ego...

Philaphlous
Philaphlous's picture
Offline
Last seen: 3 months 2 weeks ago
Joined: 12/01/2016 - 20:31
Posts: 57
Location: United States

Opened my 2nd to last battery pack from ebay. Supposedly some Chinese 2200mAh cells. Not bad! Better than the rest of the bunch! Accidentally pulled off some heat shrink around the casing of a cell and connected the positive nickel tabs to the negative on a battery…BAM! huge thing of sparks and the entire nickel melted away…lol! Fortunately all the batteries are still good! Good thing I got a 2nd heat shrink wrap for my batteries! Save them from possible shorts!

kennybobby
kennybobby's picture
Online
Last seen: 2 min 34 sec ago
Joined: 05/10/2017 - 09:13
Posts: 103
Location: huntspatch, alabama

Would you still have that 40V Ryobi pack from the original post? i’m interested to reverse engineer the BMS board in that pack and wondered if you could post the part numbers of the 2 big IC chips seen in the pictures. i would guess that the square one is a microcontroller (TI?) and the rectangular one is a cell monitoring chip (LT?).

If we could hack the BMS then it might be possible to figure out why the packs are shutting down and how to repair them and then re-use the entire pack.

thanks, kenny

Speed4goal
Offline
Last seen: 2 months 4 days ago
Joined: 06/11/2016 - 13:03
Posts: 845
Location: Bay, St. Louis Mississippi

kennybobby wrote:
Would you still have that 40V Ryobi pack from the original post? i’m interested to reverse engineer the BMS board in that pack and wondered if you could post the part numbers of the 2 big IC chips seen in the pictures. i would guess that the square one is a microcontroller (TI?) and the rectangular one is a cell monitoring chip (LT?).

If we could hack the BMS then it might be possible to figure out why the packs are shutting down and how to repair them and then re-use the entire pack.

thanks, kenny

I maybe able to help soon. I still have one I havnt taken apart yet. My 4th one. In 3 months I’ve found 4 they seem to fail a lot. But the cells are still almost at original capacity. I’ve been putting it off being is highly disappointing they are 1300mah cells. When other brands have much better cells in them. A lot of people say there’s have Samsung 13q. All of mine so far have lg 25 amp 1300 cells not samsung. I’ve just been using them mostly for vaping since they are high drain. Or night lights. Each pack had a few cells that were shorted out. In 60 cells 18 were completely dead. The other 42 perfectly fine. Just low capacity. Figure I’ll hang on to them for hurricane season. In case power is out for a few days or a week

On a positive note I found a brand new pack a display I believe in the bin still had new plastic smell and the battery light worked on it. Had 5 Samsung 20q inside. At 2200 capacity roughly. So those are my batteries for the Q8 I’ll put solder blobs on 4 of them

kennybobby
kennybobby's picture
Online
Last seen: 2 min 34 sec ago
Joined: 05/10/2017 - 09:13
Posts: 103
Location: huntspatch, alabama

ok i can answer my own question now.

There are two versions of BMS boards made by TTi in the ryobi OP4026 40V packs.

model # board # date
13086012 280146 jan 6, 2011
13086045 280296 dec 17, 2013

i had guessed just opposite for the two chips on the board: the square quad pack U3 is the battery monitoring chip by O2 Micro, OZ8940ATN; and the rectangular 28-pin SSOP designated U2 is a PIC16F1786-1/SS microcontroller.

i had found a 40V and a 18V pack in the recycle bin at HD. The 40V is completely dead, the cells have been totally drained. The other pack indicates 9V when reading from the outside terminals, but all the cells read 4.0V when opened up.

Depending upon the model, there are either one or two big FETs (IRF1404Z) on a heatsink on the bms board that switch the low side of the pack closed/open that functions like an ON/OFF switch. Something must be causing this to stick ON and draining the packs—there are a huge number of dead packs for sale on ebay, plus lots of posts from folks with problem packs. These cells should last 10 years—something is killing them early…

These packs, like nearly every other power tool brand, are built under patent 7554290, invented by Todd Johnson et al, and assigned to Milwaukee Electric Tool Corp. The BMS has no shutoff or low-power mode, and it gets it’s power from the pack—so it is constantly draining the pack. Too bad we have to pay these guys royalties for a POS system, there are better solutions out there e.g. Texas Instruments

ImA4Wheelr
Offline
Last seen: 3 days 11 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7444
Location: SC

^

Thanks for the info kennybobby.  Not sure what it means, but it seems like good info for those that know about such things.  I just pulled my 5th or 6th one from a recycle bin today.  So far, 2 of them had completely dead cells and the others had cells that acted as if new (Low resistance, full capacity, stay cool when charging and discharging a 1 amp, normal warming under high current loads, etc.). So it seems the bms has some other issue that prematurely ends its usefulness.  I heard (don't know if it is true) the internal bms disables the pack and intentionally fully discharges the cells when it deems the pack unsafe.

Great cells for around the house lights that don't need long run times.

kennybobby
kennybobby's picture
Online
Last seen: 2 min 34 sec ago
Joined: 05/10/2017 - 09:13
Posts: 103
Location: huntspatch, alabama

i think you are right—the controller can disable the pack by opening the FET, which is device 480 is this simplified patent schematic image (440 is the microcontroller).

ImA4Wheelr
Offline
Last seen: 3 days 11 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7444
Location: SC

^

Interesting.  Are you thinking those resistors may be used to do a controlled discharge of the cells when certain parameters are met?

If that is the case, it is best one break down a found pack as soon as possible to hopefully liberate them before getting below 2 volts/cell (IIRC what the 13Q can safely discharge down to).  I will try to open up my pack tonight and measure cell voltage and voltage drop across those resistors.

kennybobby
kennybobby's picture
Online
Last seen: 2 min 34 sec ago
Joined: 05/10/2017 - 09:13
Posts: 103
Location: huntspatch, alabama

The 40V ryobi are very difficult to desolder without shorting and arcing. They put a huge amount of solder on each cell connection and it requires a very high wattage solder iron and lots of solder wick to disassemble if you want to preserve the circuit board. If you don’t care about the board then it should be easier. i wanted my board for reverse engineering purposes.

Here is another patent schematic showing the cell draining/balancing resistor circuits [460’s], which could be used for draining all the cells in the event that a safety feature is triggered (out of range for temperature or voltage, defective temperature sensor, blown fuse, etc). i hope to trace the actual board circuits and identify all these components, probably in another thread so as to not hijack too much here…

ImA4Wheelr
Offline
Last seen: 3 days 11 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7444
Location: SC

^

I can send you my best board if your wanting one still.  Just PM me the address you want it sent to and I will have it off to you.  As you stated, they are difficult to tear down.  So I don't think I have one without some damage.

I opened the pack and the cells were down to about.48v.  I didn't have time to follow traces and try to find the resistors you diagrammed above.  There are about 12 510ohm resistors and they are the biggest ones on the board.  10 of them are probably the ones in question.  I tests voltage across some of them and got a reading of about .01 (IIRC).  So it appears the pack is actively discharging the cells.  When the "test" button is pressed, the 4 LED's that normally show level of charge all flash off and on.

 

kennybobby
kennybobby's picture
Online
Last seen: 2 min 34 sec ago
Joined: 05/10/2017 - 09:13
Posts: 103
Location: huntspatch, alabama

Yes those 510 Ohm resistors are designated RF1 – RF10 on the board and connected to each 2-in-parallel Cell as shown in the schematic above where they are connected to the – end of each pair. If those were removed it would isolate that pair from the drain circuit. i don’t know how long it would take to drain a pack, best not to wait to salvage the cells. (EDIT note: The 18V ryobi packs have 5 cells and use 51 Ohms for the RF resistors)

i think RF11 and RF12 are in circuits that provide power for the digital section so those could be removed as well to just turn off the controller and stop the bleeding. i ended up taking them all off the boards.

i have 3 packs that indicated bad, one was actually overcharged at ~42.8 V, the others were around 3 to 4V, with cells at .2 to .4. i put them on a power supply and slowly stepped up in 1V increments while monitoring the current and temperature.

The 4V pack immediately took current at 50-90 mA and then it tapered back to about 25mA, then i incremented 1V and repeated this until the voltage got up to ~23 V for the pack. At that point the current draw was increasing with each 1V increment, , e.g. 200 to 300 mA. Again i let it hold at that voltage until the current dropped to ~25mA, then increment. Got the pack up to 32V and stopped, will see how it is in the morning.

The 3V pack didn’t seem to draw any current like the other one did—i stepped it up from 3 to 23 in 1 V increments with little to no current flow, then at 23V it started to draw/charge at 25mA, and after a few more increments it soon started behaving like the pack above until reaching 32 Volts, will check it tomorrow.

On the 42+V pack i had removed the fuse between the top and bottom modules (2P5S bricks that make up half-packs). Over just 2 days the bottom module had been drained off to 18 V, whereas the top half was still reading high at 22.8. The digital controls seem to be powered from the upper half, and likely sensed the “blown” fuse and initiated the drain-off for the bottom half. i connected a resistor and bled the top down to 20, and charged the bottom up to 19, will check it in the morning to see how it holds.

So long story short, nothing thermal was noted, but that doesn’t mean they are safe and good to go. Metal dentrites grow inside a cell during any charging that is done after an over-discharge event. These are sharp shards of metal that will puncture the plastic separator sheet in the cell and cause an internal short circuit, which leads to thermal runaway—much heat and eventually fire. So don’t try doing this unattended, recharging after a discharge below 2.5V is not a recommended practice and they can go off AT ANY TIME and burn down your garage, house or trailer. If it happens while you are sleeping, then you might just wake up dead…

aarone
Offline
Last seen: 2 months 1 week ago
Joined: 05/22/2017 - 01:21
Posts: 32

My first recycle bin pull as a registered member. Nothing super special but a 20V worx Li-ion pack. Had a piece of blue painters tape with “bad” written on it. 11/2015 mfg date. Every cell measured 4.05v. So maybe the board in it died but every cell in it appears to be good.

http://i.imgur.com/SWot1Uf.jpg

dchomak
Online
Last seen: 11 min 40 sec ago
Joined: 03/17/2012 - 20:10
Posts: 3882
Location: Connecticut

kennybobby wrote:
The 40V ryobi are very difficult to desolder without shorting and arcing. They put a huge amount of solder on each cell connection and it requires a very high wattage solder iron and lots of solder wick to disassemble if you want to preserve the circuit board. If you don’t care about the board then it should be easier. i wanted my board for reverse engineering purposes.

Here is another patent schematic showing the cell draining/balancing resistor circuits [460’s], which could be used for draining all the cells in the event that a safety feature is triggered (out of range for temperature or voltage, defective temperature sensor, blown fuse, etc). i hope to trace the actual board circuits and identify all these components, probably in another thread so as to not hijack too much here…

![img]http://i.imgur.com/2qoJco5.png?1[/img]!

You may be right on a “fatal discharge” circuit being built in to these packs, I don’t know.

I have always assumed that the reason there are so many like new packs in the recycle bin is because the store or customers make the mistake of fully discharging a pack and leave it for an extended time in that state.
With all the monitoring circuits in the BMS board, there HAS to be some parasitic drain, and if there is, it wouldn’t take much time for the pack in a fully discharged state to drain further to a point of no return. In other words a permanently damaged pack.
Take a look at this discharge curve I pulled from the thread

I had to estimate the capacity of an 18V drill pack, here is how I did it.

From that thread, the area under the curve is approximately the same as the area bound by the red lines and represents the Amp-Hour capacity of the pack. The horizontal red dashed line is the cutoff voltage.
Now notice the blue arrow, it points to an area under the curve to the right of the vertical red line that is bounded by the discharge curve.
It is a very tiny area!
The graph only goes down to 2.3V, but as you can see, if you were to continue the discharge curve any further, you wouldn’t increase that area by very much at all. There is very little capacity past the shut off voltage.
What this means is that if there is any parasitic drain in a pack, leaving a fully discharged pack in that state can kill it!

That is why I believe I find so may “like new” packs in the recycle bin that are dead. Most come, I believe, from tools on display in the stores.

Pages