Here is a good used source for 18650 batteries

[redwire]

Re: Here is a good used source for 18650 batteries

They look like a really good deal.
Say 2.6A/cell so 26A (2s10p) I think the pack is near the (interconnect) limit, you would go up to 3S or 4S if you wanted to pull more power.

The missing middle cells, it's the best place because they would otherwise be surrounded by cells and see the highest heat which is not good.
It would be interesting to calculate the heat, using ESR value to see how many W the cells dissipate during high drain. The Boeing 787 lithium battery fires they added room and ceramic spacers and did not stay with 3x3 packing where a cell is surrounded by others on all sides.

[eccerr0r]

Re: Here is a good used source for 18650 batteries

LOL dummy cells in center! Was it for heat distribution or just a lower rank sku?

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is the link for 4.2 volt @ 26 amp hour battery packs that I mentioned above
I bought the amount that I need and there are still some left

https://batteryhookup.com/products/new-7-2v-30ah

I have tested one battery pack it does test at a little bit over 26 amp load test parameters are 4.2 volts down to 2.5 volts

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here are the battery pins that I mentioned above

https://www.ebay.com/itm/18520310170...3ABFBMuJaYocJh

Yea I know that you are going to say that they are expensive if you have a lot of battery pins but I was showing you how could use this with the cutting board that I also mentioned above

These are good quality pins I used them before on my battery testing machine I have not bought pins from this seller BTW

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

No it does not however it can tell you if the cells are having issues if the ESR value is high but will not tell you if the battery cell can be balanced to each other this is SkyRc battery tester or the battery machine that I have referred earlier in this post comes into play

If fact I just bought very good battery packs that are 4.2 volt @ 26 amp hour that I found the battery packs for the battery operated compressor that I have talked about in another post where the battery machine is going to let me know if each battery pack has the same amp hour rating or not

I am not going to post the link for them right now because I might have to buy a few more if amp hours not real close to each other because they have a limited amount of these battery packs available these are very good quality battery packs some of the best ones I have seen from them so far

I will post a seller that sell good quality battery pins and can use a cutting board from Sam Club that is very good for this purpose they cost about $9.00 for one I got the idea from Battery Hook Up Facebook page someone did this to test Ryobi 18 volt battery packs I see no reason why you could take idea and modify it for single battery cell you just have to have a way to cut the cutting board into strips or for more than one battery cell

By the way PLA can be used for making battery holders just make the thickness right I see no reason why it would not work properly because I made a set for battery holder that was made for 32600 and works very good the one thing that I would do differently is I would make the inside diameter a little bit bigger so it would be easier to install and remove the battery from the holder

I will find out what type blade you have to use to cut this type of plastic because where I work at now they cut a lot of this type of plastic I have cut two cutting boards for a couple of projects and it nice cut edges

[eccerr0r]

Re: Here is a good used source for 18650 batteries

holy crap that's expensive... If you have a lot of cells, that will add up fast. Was thinking of 3d printing something but getting the force needed to reduce connection resistance is hard with PLA.

btw, I tried measuring ESR of the cells that came from that pack with my ESR meter... wow these are clearly new-ish cells, compared to the older cells I have. the older cells are a fraction of an ohm, the RMA cells are less than that. I tried that deadish cell that was able to revive in one of those HFT "free" flashlights (with an adapter to get rid of the 3xAAA thing) - yes it's very bright...

Alas now that I know of the esrs being different, now this becomes even more of a balancing problem... and esr has nothing to do with capacity...

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is the 18650/21700 battery holders that I was talking about

https://www.ebay.com/itm/155075483177?var=455251086921

[eccerr0r]

Re: Here is a good used source for 18650 batteries

TBH someone needs to find a way to recycle li-ion battery packs like they do in lead acid. however the design of these cells are simply not up for automated recycling, at least lead acid cells are huge, nearly 100% lead, and you can easily process them large batches at a time.

Li-ion cells are a mishmash of materials and hard to automatically process, plus the risk of self immolation by merely opening them ... lead acid batteries, once you drain the acid, are virtually inert.

[eccerr0r]

Re: Here is a good used source for 18650 batteries

Yeah both the mower and the scooter are like 10A sustained (probably 20A+ during inrush) alas perhaps I could build a homemade BMS, just need the cells.

I probably need to get up to 6S10P before I can think of using these li-ion packs for the scooter/mower, hooboy... but definitely could use the pack for other purposes before hitting that mark.

BTW that bad pack I got, the BMS was 6S of course, but it was cheaped out!!! It grouped cells in batches of 2, so it didn't monitor interstitials and that's probably the cause of its early demise!

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Later on today I post a seller on EBay that has a solution for 18650 and 21700 battery holders they are very good quality and are not that expensive for what they are one nice thing about them is that they can be joined together and they have crimp terminals that come with each battery holder they also come with a top cover as well

I use them with my battery testing machine and they work very well

You can also find BMS protection boards on eBay as well very reasonable price now if you want BMS balancing production boards now these are more expensive and sometimes hard to find in the high amperage version a lot more expensive

[eccerr0r]

Re: Here is a good used source for 18650 batteries

hmm... after pulling the pack apart, I was able to charge one of the three cells that were less than 0.5V. I'm not sure how bad the self discharge is yet, but suspect it will be bad but the worst part is that I pulled the straps off of it, so no way to connect to it anymore other than if i get a holder with springs or a tab welder.

The other two shorted cells are still no-go, won't charge.

Have enough cells now to build a 4S3P pack, now need to see if I can rip apart some other packs to see if there are any salvageable cells...maybe up to 4S4P or more. Or perhaps I should standardize on 6S somehow (I don't have any 6S BMS, only 4S BMS), so I could use it to run my mower and e-scooter (both are 24V SLA at the moment) perhaps.

Ponder Ponder...

[eccerr0r]

Re: Here is a good used source for 18650 batteries

Damn.
I got a "21.4V" 4Ah pack "new RMA" pack for $1 from the returns processor. Seemed a bit too light and small for 4Ah but anyway...

When I opened it... It was a 6S1P Li-ion... and 2AH 18650 cells in it!

Grr.

Add insult to injury, 3 of the 6 cells were shorted, 2 were at 3.5v, and the 6th was at 2.5V.

Oh well, $1 for 3 18650-2Ah cells...not great, and who knows what the true capacity of the cells are, will need to test them further...

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

I would agree with you but what I find is that a lot of BMS are not very kind to the batteries that they are supposedly there to protect but in the same token they are also inexpensive to buy them as well so what can you expect cheap BMS protection boards

Unfortunately this BMS board does charge it to 100% and discharges to probably to around 20% so in this respect it is also not real kind to the batteries either but because I going to use some of them on a solar panel I not real concerned about this because you have trade offs so probably even this BMS protection board might over time degrade the batteries as well just probably not as fast at least that what I can hope for

Depending on how much power this LED module takes in current and running from sunset to sunrise every day so we shall see what kind of results I will get with what I have in mind

Because if I remember correctly this LED module current draw is around 300 milliamperes so little over 3 hours of running time would be around 1 amp hour if my calculations are correct that should be around 6 amp hours or a little bit higher than this

[ChaosLegionnaire]

Re: Here is a good used source for 18650 batteries

One final note about this BMS protection board is that when it has reached the cutoff point and you discharge it a little bit to reactive the charging mode it is still locked and will not allow you to charge it until you get below 12 volt before it reactive the charging mode very interesting the way this BMS protection board works.

me three! i like this too. this is so that the cells dont get constantly charged while already in a high state of charge. i have heard momaka say that lithium cells dont like being charged more than 75% or discharged less than 25%. these two things shorten the charge cycle life of the cell and u end up with degraded cells that cant hold a charge anymore.

so whoever built that bms is a genius! kudos to panasonic or whoever is the oem of this medical equipment battery pack for actually knowing how to properly design a bms that extends the life of lithium batteries as long as possible so that there's less lithium battery e-waste which is highly pollutive and toxic to the environment!

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is another item that I bought from Battery Hookup this is the solar panel that I mentioned earlier in the above post

https://batteryhookup.com/products/5...el-new-edition

I still need to get the power cables from the company that makes this solar panel to be able to use it for the battery packs that I also mentioned earlier in above post

Now that I have battery packs that I can use for this solar panel I now need to buy the cables for it

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is an update on this item

https://batteryhookup.com/products/n...-2900mah-cells

The BMS protection board specifications are as follows

Cutoff voltage at discharge is 7.9 volts cutoff voltage on charge is 12.81 volts ( this is a little higher than I would like but it not as bad as I seen before but the lockout feature is what I like about this type of controller )

The fuel gauge is weird in that from 9 to about 10.50 volts it flashes one LED light until it get above 11.50 volts when it gets above 12.00 volts all 5 LEDs are on

The last picture is of the controller ic chip
Here is the data sheet for the controller ic chip



When I put the power supply wires on the BMS protection board and put it back in the enclosure I will recharge the battery pack again to 11 volts and then start the charging cycle again but keep pushing the fuel gauge button to get a more accurate idea of what specifications this part of this circuit has for my own information I will also post the results

One final note about this BMS protection board is that when it has reached the cutoff point and you discharge it a little bit to reactive the charging mode it is still locked and will not allow you to charge it until you get below 12 volt before it reactive the charging mode very interesting the way this BMS protection board works

I will post some pictures of the BMS protection board and the power supply wires and what it will look like after it is put back together

I have a couple of solar panels that I want a BMS protection board that would not allow the batteries to become over charged I found what I was looking for in a BMS protection board

One note the cutoff voltage is not 2.640 volts the cutoff voltage voltage is actually 7.90 volts

The amp hours are 9.604 which is what the data sheet says that it should be for 3 cells in parallel

This is the best battery pack that I have bought from Battery Hookup so far
I only had one other battery pack that I like the BMS balancing protection board unfortunately I only have one pack that is this way the other battery packs were only BMS protection board but it was only a 8.2 volt battery pack not going to be able to use it on a 12 volt solar panel because I only have one battery pack that is that way

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

https://batteryhookup.com/products/n...-2900mah-cells

This to me is a very good buy however you do have to do some work to able to use them I would highly recommend that you open the enclosure and remove the connector and put your own wires or connector to the board before you charge this battery pack for best results

I would also check and make sure that the BMS protection board works correctly before you put it in service for best results I will post the testing results of this battery pack maybe later on today or tomorrow

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

https://batteryhookup.com/products/n...-2900mah-cells

I did some testing on these battery packs that I bought from Battery Hookup and they are nice however there are couple of things you should know one is it dose have a BMS protection board but it is kind-a cork-e the way it works

One the cutoff voltage is 4.25 per battery cell (not real thrilled about this
Second the fuel gauge is weird in that from 9 to about 10.50 volts it flashes one LED light until it get above 11.50 volts when it gets above 12.00 volts all 5 LEDs are on I left it charging on own once it got passed 11.30 volts until this morning when I checked the fuel gauge again

The BMS protection board hookup is first three and the last three pins on the connector are used the rest of the pins go no where on the board

One final note about this BMS protection board is that when it has reached the cutoff point and you discharge it a little bit to reactive the charging mode it is still locked and will not allow you to charge it until you get below 12 volt before it reactive the charging mode very interesting the way this BMS protection board works

I kind-a like this because I can use this BMS protection board with a solar panel and not worry about it severely over charging the battery pack which on some BMS boards when you remove the charger and reapply the charger again it charging again and it does not matter how many times you do this it keeps charging not at a high current but just the fact it does this I not thrilled about that the fact that some BMS protection board do this crap

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is another offer from Battery Hookup these are very high current batteries

https://batteryhookup.com/products/n...ah-cell-module

Here is another one that is high current batteries

https://batteryhookup.com/products/f...pr_seq=uniform

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is a new offer from Battery Hookup

https://batteryhookup.com/products/n...-2900mah-cells

I have bought a box of them and have open one and the battery voltage was close to 9.0 volts I charge it slowly at 200 milliamperes until it got to 11.3 when I need the power supply to do some troubleshooting on my son semi truck that I have been working on

I might put it on the battery testing machine and post the results when I have the results