Here is a good used source for 18650 batteries

[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

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

[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?

[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.

[stj]

Re: Here is a good used source for 18650 batteries

the 787 thing was suspicious - i'm not sure it was the batteries.
a lot of special cargo was on that plane.
you would think they would have done tests with the batteries and charging system out of the plane to determine what happened, but no.

it reminds me of when the u.s. navy shot down another boeing and then caused untold costs and problems for the industry by making up some fiction about an alleged fuel tank explosion.
even while the canteen area had clear signs of being almost cut in half by an expanding-rod warhead.

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

No there two blank spaces nothing there and I would not be surprised if that is the reason they are blank for heat dissipation would be my guess but I like the idea of this though because they are not sandwiched tightly together

There is space between the two groups of battery cells as well

[eccerr0r]

Re: Here is a good used source for 18650 batteries

well have to think about it this way too, with more cells there, each cell would produce less heat (because it's shared!) ... so it's totally the consumer that dictates how much heat the cells generate. If you draw less (per cell -- if it come to it), the cells would heat up less.

I'd imagine there's a better way to place cells to give each cell more space between each of them than just putting two dummies in the center. Alas it's an easy solution.

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

This battery pack does have a BMS protection board I going to see if it useable when I receive the other 5 battery packs I have to decide how I going to use them but I kind-a thinking that I might cut them up so that there 5S and make a battery pack like this but I quite sure yet on the details yet

[eccerr0r]

Re: Here is a good used source for 18650 batteries

yeah form factor of the pack is annoying. mower pack is a big block, but that doesn't work for transportation packs which tend to be long and thin.

to choose between 3S, 6S, or 4S(which I have several bms boards for)... argh. Well, at least for things like 10P I can use lm324 to design a bms/balancer where in a 1P it'd waste too much power...

[ChaosLegionnaire]

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...

fake capacity cheap china cells strike again! on aliexpress, they have 9ah 18650 cells and li-po cells flying around the place. russians bought them and were not amused about the overpromised, exaggerated capacity. lol!

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

whats the whole complete part number of those cells? it doesnt say. are they samsung sdi icr18650-26j m flat-top cells? max discharge current according to the datasheet is 5.2a continuous? there is also a review of the batteries at this link: https://lygte-info.dk/review/batteri...(Pink) UK.html

apparently, u can "overclock" this model of 18650 cell up till 7a max discharge current continuous without capacity loss! very nice! i intend to rebuild a laptop battery pack that has 75% wear level on the cells so high discharge current cells would work well for this purpose. not sure if 7a max discharge is enough for e-cig smoking and vaping usage... hehehe! im getting more adventurous during my lithium battery playtime! pray-tell i dont self-immolate like eccerr0r said and end up on the news for the wrong reasons. lol!!

[eccerr0r]

Re: Here is a good used source for 18650 batteries

oh here's the 6S1P BMS for the "4AH" pack...
only connections to the 6 batteries are the B+ B4 B2 and B- terminals.

Though it appears to have temperature sensing, there's no balancing that I can see, but does have protection. and probably fuel gauge capability. hmm. what can I salvage from the board....the mosfet? :\

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

You could use it as is just remove the battery terminals off the board and use wires instead of metal terminal posts if you need a 24 volt battery power supply that way you can use the temperature sensor on the battery pack

The easiest way to remove the metal battery terminals from the board is to put new low temperature solder on it and heat the solder until it flows and remove it from the board while it still flowing

[eccerr0r]

Re: Here is a good used source for 18650 batteries

but it's a garbage bms because it does not check some interstitial nodes! Need to find one that checks all interstitials.

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

but it's a garbage bms because it does not check some interstitial nodes! Need to find one that checks all interstitials.

What is the meaning of the words in red I googled it but the word meaning comes back as medical term unless it is misspelled

[eccerr0r]

Re: Here is a good used source for 18650 batteries

read the wikipedia page and replace cell...with cell.

BTW: note that 6S has how many connections, and how many battery connections are there on the BMS board I have (hint: there are 4). Should be real easy to figure out what interstitial means in this case.

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

read the wikipedia page and replace cell...with cell.

BTW: note that 6S has how many connections, and how many battery connections are there on the BMS board I have (hint: there are 4). Should be real easy to figure out what interstitial means in this case.

Did you mean this word instead “ Interconnects”

[eccerr0r]

Re: Here is a good used source for 18650 batteries

No... though in some cases it can be synonymous.

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

They are running a sale on Samsung battery that are made for power tools for a limited time

https://www.18650batterystore.com/pr...sung-25r-18650

There other models and brands that are also on sale I get there new letters this where I bought the 21700 a few months ago they are not fakes

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

These battery are testing new they must not have been cycle very many times the discharge looks excellent and well worth the money

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

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

I intend to rebuild a laptop battery pack that has 75% wear level on the cells so high discharge current cells would work well for this purpose.

One thing you should consider and know is that on some laptops battery packs when you go to put new battery cells in them if they have micro controller in them it locks the BMS board and will not function properly anymore

From what I understand if you keep power on the battery terminals supposedly you can keep it from locking up but I have not tried this myself so I can not tell you if it works or not