Here is a good used source for 18650 batteries

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is another offer from Battery Hookup

https://batteryhookup.com/products/1...0-3-7v-5000mah 21700 battery cells $1.64 per cell X 110 battery cells in battery pack = $180.00

I bought one of these to replace some tool battery packs that are very unbalanced
It took a few hours to disassemble this battery pack but well worth the money because I have already charged up four of them and from 3.1 volts to 4.2 volts was well over 4 amp hours now discharging them down to 3.0 volts where the normal voltage roll of voltage usually is

The voltage looked good on each battery cell bank very balanced between battery cell banks

The temperature of the battery that you are seeing in normal for these battery cells it is set to read in *F instead of *C

Test results so far are 1744 milliamperes hour at 3.83 volts @ 1.47 hours

Parameter are as follows

The graph function is very primitive but gives you enough data information to know if you have a problem with the battery cell

SkyRc MC3000
charging voltage 4.2
resting time is 240 minutes to allow enough time for battery temperature to reach room temperature again for the second phase of the testing
discharging voltage 3.0
amperage is set to 1.00
battery temperature cutoff is set 40*C

The temperature that you are seeing for this type of battery cell is normal it set to display in *F but you have to set it in *C

One note the temperature reading on the last battery cell is always a couple of degrees off from the other battery cells I am thinking that just a little off because even when there no battery in it it always shows a couple degrees different

One other note the results are being shown on a very old iPad that is not supported by Apple anymore but it good enough for doing battery testing for this battery testing machine iPad screen is set to not to shut down the screen meaning that it set not to shut off unless I use the power button to turn it off / because if it not set this way when you wake it back up sometimes it resets it self and you lose the data

My other SkyRc battery testing machine is also the same way you have to keep the screen from going off or you lose all the data as well it the one that can do 6 battery cells for up to 24 volts battery packs

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is another offer from Battery Hookup

https://batteryhookup.com/products/c...-batteries-new

These are very nice battery cells for the price but there is one thing you need know about these battery cells is that they are not balanced battery cells they are from exactly the same amp hours to as much as half amp hour difference between individual battery cells

I would highly recommend that if you buy them make sure that you have a battery testing machine of some sort so you match the amp hours

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is another offer from Battery Hookup

https://batteryhookup.com/products/1...0-3-7v-5000mah 21700 battery cells $1.64 per cell X 110 battery cells in battery pack = $180.00

I bought one of these to replace some tool battery packs that are very unbalanced
It took a few hours to disassemble this battery pack but well worth the money because I have already charged up four of them and from 3.1 volts to 4.2 volts was well over 4 amp hours now discharging them down to 3.0 volts where the normal voltage roll of voltage usually is

The voltage looked good on each battery cell bank very balanced between battery cell banks

When I said that it took a few hours to disassemble the battery pack I meant that it took that long to remove all the tabbing from every battery cell

One note about the description from Battery Hookup about the BMS protection board does take a little doing to remove it I would recommend that you cut the wires from the BMS board before you try to completely remove it from the battery enclosure it will make it easier to install your own BMS board because there are small tabbing soldering holes for the BMS board wires to go from your own BMS board

To reconfigure the battery voltage would be fairly easy to do you would need to cut the battery tabbing down the length of battery cell bank or just remove it and use single row tabbing instead but not the amp hour reconfiguring would much harder to I am not saying it impossible but would require a lot of work the reason I am saying this is because the tabbing is very easily ripped off of battery cells if not done properly because it the fuse type of tabbing that was used to me the easiest way to do this might be use a small cut off disk and lightly cut the tabbing off enough to separate the battery cells from each other

You could turn it from 110 amp hour to 50 amp hour and get a higher voltage if you want to do that

If I buy another one when I have the money for it and if Battery Hookup still has them in stock

I would like to take one and reconfigure it so it would be 12 volts and who knows how many amp hours I could get from this battery pack the enclosure is very well made one note I would not recommend removing the battery cells from the battery cell holder it would not be very easy to get all the battery cells to line up so you snap the battery holder back together it does have screws that hold it together

If I did buy another one I would probably just test each battery cell bank and not each individual one the test would still be valuable because you would know how many amp hours each bank would have and if each bank basically has the same amount of amps hours

Test results so far are 1744 milliamperes hour at 3.83 volts

[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

One note after I did the first battery pack and I saw that the roll off voltage was around 6.00 I set the parameters 8.4 charging and 6.0 for discharging

Well I have tested 5 of them so far and they all are very very close to each other and I have already put the two and half battery packs on a cutting board for the first level the second level has two battery packs on it and now I am testing the other battery pack to cut in half for the second level once I do this I will have to wire the the battery packs together to make a 20 volt battery pack with the BMS protection board and put the charger together to charge the battery pack for the battery operated compressor I used a marine battery enclosure and a cutting board to mount the battery packs I will post some pictures of it when I get the first level wired together

The third level will have the BMS protection board with an inline fuse holder

The two half battery packs I going to reconfigure for another project and use the remaining half’s because they do not have enough tabs on one half of it but it still can be mounted on something else

I was very pleased with how the battery pack mounting went the bottom of the battery packs have two mounting round tubes that stick down about 1/4” so I drilled two round hole to accommodate the two round tubes which have a hole in the center of the tubes that are on the bottom of the battery pack and they are very secure to the cutting board used #6@1” metal screws for the mounting of the battery packs

[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

[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

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

[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

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

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

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

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

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

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? :\

[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

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...

[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

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

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

[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.