18650 cell question

anotherkiwi

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i was looking at these cells,
https://www.ebay.co.uk/itm/Li-ion-3-7V-3000mAh-High-Power-18650-Battery-8pcs-YCDC-For-Strong-beam-Torch/332420095032?_trkparms=pageci:bb001247-2aa3-11e8-a6fe-74dbd18036af|parentrq:38fa0c121620abda5821dc97fff9f036|iid:1&_trksid=p2481888.c100675.m4236

my thinking was build a 10s8p so the vauts should be 42v would give me an 18A battery so 650w hours and the A distage of what your saying would be 20A so enough for my bafang 250w mid drive. and with a bit of discount probably £125 for the cells so quite cheep.

or passably a waste of money
Do you have an issue with quality brand name cells? :confused:

Try here: https://www.nkon.nl/rechargeable/18650-size.html
 

billym1967

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so simple answer is of course i don't have a problem with quality brand named cells. and i bought my last 2 lots of cells from there. but if i can buy a cell 50p cheeper that doesnt have a well known name and still does the job then i will buy it, 50p to 60p a cell cheaper soon adds up. i built my own battery because i got better quality cells and save some money. so probley gonna save £40 or £50 on a big battery.

as we all know just because something has a brand name, it doesnt always make the extra cost worth while.
 

wheeliepete

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By all means try the cheaper cells, we would all be interested in how they perform. There are many batteries on sale and in use made from them. I would try and find a source in the EU as cells sent freepost from China run a risk of being destroyed or held at customs because the sellers never use the correct transit methods.
 
D

Deleted member 4366

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i was looking at these cells,
https://www.ebay.co.uk/itm/Li-ion-3-7V-3000mAh-High-Power-18650-Battery-8pcs-YCDC-For-Strong-beam-Torch/332420095032?_trkparms=pageci:bb001247-2aa3-11e8-a6fe-74dbd18036af|parentrq:38fa0c121620abda5821dc97fff9f036|iid:1&_trksid=p2481888.c100675.m4236

my thinking was build a 10s8p so the vauts should be 42v would give me an 18A battery so 650w hours and the A distage of what your saying would be 20A so enough for my bafang 250w mid drive. and with a bit of discount probably £125 for the cells so quite cheep.

or passably a waste of money
To avoid wasting your time making a boat anchor, you should only buy branded cells from a reputable dealer, like Nkon.

https://eu.nkon.nl/rechargeable/18650-size.html
 
D

Deleted member 4366

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so simple answer is of course i don't have a problem with quality brand named cells. and i bought my last 2 lots of cells from there. but if i can buy a cell 50p cheeper that doesnt have a well known name and still does the job then i will buy it, 50p to 60p a cell cheaper soon adds up. i built my own battery because i got better quality cells and save some money. so probley gonna save £40 or £50 on a big battery.

as we all know just because something has a brand name, it doesnt always make the extra cost worth while.
I've just disassembled a faulty 70-cell battery to see why it had reduced capacity. The cells were unbranded. 50% of them were leaking:

20180318_144518.jpg
 
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Danidl

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so simple answer is of course i don't have a problem with quality brand named cells. and i bought my last 2 lots of cells from there. but if i can buy a cell 50p cheeper that doesnt have a well known name and still does the job then i will buy it, 50p to 60p a cell cheaper soon adds up. i built my own battery because i got better quality cells and save some money. so probley gonna save £40 or £50 on a big battery.

as we all know just because something has a brand name, it doesnt always make the extra cost worth while.
Where do these cells come from. ? There will be a limited number of lithium cell manufacturers, with chemical laboratories and QC facilities. They produce cells. As with all manufacture products there will be a distribution curve of performance. .. perhaps when the machine was started in the morning the mixing of the ingredients was a little off optimum, the alignment was going out of kilter ..anyone linked with manufacturing knows that these happen.? In some cases if a few items in a batch are found defective, the entire batch is scrapped., even though 80% might be ok.
There are rumours that in some Chinese factories moonlighting takes place where the machines are used to manufacture without the knowledge of the management
.
What happens to substandard cells or batches? .... often it is not possible or economic to simply strip them apart and recycle the innards They are sold off as scrap value and then resold by third parties... That is what you are buying with unbranded product...
 

Nealh

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there from china, few sellers have them but i am stuggerling to find any info on them.
3000mah some crappy no name cells have been known to only produce 10% of the expected mah and CDR ?
8 cells for under £14 is a joke, there is no way these are suitable for ebike use.
 

soundwave

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May 23, 2015
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just take a zero off the end of there mah rating and its about right then the same with there led light lm output esp from china lol ;)

look on you tube for capacity tests of 18650 cells there cheap for a reason tho id not even give 50p for them.

go to pound land and get a load of 1 cell power banks for a quid each you might get lucky had some 2600mah from some of those and tested near bang on but some were a dead flat also ;)
 

Nealh

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there from china, few sellers have them but i am stuggerling to find any info on them.
It took me a bout 2 mins to find out their fake.
Vid on you tube and they barely produce 900 - 1000mah and voltage is awful at 4.06 - 4.1v no CDR found but expect there not even 1a rated.
Something else doesn't weigh up literally with these cells the weight 36g each.

Buy pucker cells and save wasting your money, four of us have told you so now.
 
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Nealh

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At some stage I will be replacing my 22 & 26F packs though I still wringing their necks until they no longer offer me the range I require. The GA & HG2 are on my radar.
 

billym1967

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i fully Take on Board what you say Nealh. and when i build my big battery i'm going for a brand cell. but i am curious now and have been reading up on how to test cell mAh. so ive bought a iMAX B6 and have ordered 4 off these batterys just to test them out.
 

spanos

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i fully Take on Board what you say Nealh. and when i build my big battery i'm going for a brand cell. but i am curious now and have been reading up on how to test cell mAh. so ive bought a iMAX B6 and have ordered 4 off these batterys just to test them out.
IMAX b6 are perfectly decent , I got one

But from memory then only can discharge test at 1a max. Which is meaningless against an ebike draw

Still, interested in your results for sure
 

billym1967

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the one ive order, witch is probably a cheaper version does upto 5a. reading up on them the proper skyrc ones are only 1a but the what i would think are not as good ones are 5a. theres 1000s sold and reading up the only issue can be is sometimes the charging vaultage is not perfect. but as i have a good charger and will be using for discharging to test the mAh then we should be good. so i try a few of these cheep batterys and also got some sony 2900mAh
 
D

Deleted member 4366

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the one ive order, witch is probably a cheaper version does upto 5a. reading up on them the proper skyrc ones are only 1a but the what i would think are not as good ones are 5a. theres 1000s sold and reading up the only issue can be is sometimes the charging vaultage is not perfect. but as i have a good charger and will be using for discharging to test the mAh then we should be good. so i try a few of these cheep batterys and also got some sony 2900mAh
You'll need to weld them up and add a 4S balance connector to use an iMax. It can't do single cells.

One of these is better if you want to mess about with 18650s:
https://www.ebay.co.uk/itm/Opus-BT-C3100-Digital-Battery-Charger-4-Slots-For-Rechargeable-4-Working-Modes/302547147965?epid=14010554476&hash=item4671371cbd:g:kfIAAOSwX61ZAc6e
 

soundwave

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the imax will charge and discharge single cells i use it all the time ;)
 

soundwave

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DSC_0558.JPG
 

billym1967

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so to continue this question.

so whats the outcome of mixing cells, are there rules for what you can do or cant do.

an example ive got some samsung 26h 2600mAh 5.2A but i also have a few sony 2900mAh 10a. can they be mixed, is there a way to do it.
 

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