...OK , I can tell by that label it's a 4s2p battery (assuming it has 18650's inside and not prismatic) 18650s are like AA size but a bit bigger..

You have 8 of these cells inside , each with an original capacity of 2600mAHr , ...

To buy these cells new , Sony or Panasonic would be about $7 each , you could risk buying unbranded cells and halve that price , they may be OK .... Don't by ultrafire , truefire or any other flashy brand that says it has a capacity over 3500 when measured the capacity is close to 1000mAHrs .... No 18650 has been made with a capacity over 3500mAHrs ...If possible buy cells with tabs it will make soldering much easier.

So you have the option of using the battery as it is with 28% capacity ... breaking it open and trying to replace the cells , risky. even with the new cells it may not work , the pack or computer could contain a chip to prevent use of refurbished battery.

Edit ,,, this post written before I saw 18 and 19

I think I have a culprit here. Check the picture below:

That one is the only cells showing signs of rust or leakage or whatever that is!
But as I think they are in parallel, 2 by 2, I can't measure that specific cell without completely detach it from it's pair!
I think these are 8 batteries, in parallel 2 by 2...
If I can find them at 7€ with that pad to easy up the soldering process, I'll buy them.

Edited;
A few more pictures:

 

Considering your 4s2p pack, it is about 36mm x 72mm x 130mm using the single cell dimensions. Rather than dealing with making such a pack (although the configuration you have may be available) you might want to consider switching to other lithium batteries (e.g., LiFePO4 or LiPo) in 4S packages that will readily fit. You may end up with a little less capacity, but the total cost based on 8x $7 will be less.

 

Yes ... often when I have a battery like that just two cells will be no good , the other 6 will usually be OK , but will be old and have reduced capacity ... you could replace just those two ... it might work for a year d before another 2 old cells pack up .... you may even be able to replace the two dead cells with one new one since the new cell will have double the capacity of two old ones ... try to get cells with tabs .

 

Considering your 4s2p pack, it is about 36mm x 72mm x 130mm using the single cell dimensions. Rather than dealing with making such a pack (although the configuration you have may be available) you might want to consider switching to other lithium batteries (e.g., LiFePO4 or LiPo) in 4S packages that will readily fit. You may end up with a little less capacity, but the total cost based on 8x $7 will be less.

Cannot do this LiFe has a lower voltage , it would not work.

 

Cannot do this LiFe has a lower voltage , it would not work.

"e.g.," mean for example, not that is. In other words, one of many options to consider. Who knows, maybe those batteries will work. Are you sure they won't?

 

You guys discuss it between you... You know way lot more than me. And if you guys know about any online shop that is good to buy such cells, please share. Time to go bed here. Will reply tomorrow.

Thanks
Psy

 

"e.g.," mean for example, not that is. In other words, one of many options to consider. Who knows, maybe those batteries will work. Are you sure they won't?

For sure LiFe will not work ... 4 in series make very close voltage to lead acid , so LiFe are perfect for replacing car battery ... 4 li-ion in series are 14.8V....
There's no need to complicate things they all cost the same ....

If I were doing this , and finances were tight , I'd just replace the two dead cells with One 18650 ,

This one is 8 Euros , it has a high capacity , so only one will have close to the capacity of two old cells ...
https://www.ebay.co.uk/sch/i.html?_...0.X18650+tabs+.TRS0&_nkw=18650+tabs+&_sacat=0

Really you should replace all eight they are cheaper for Eight , around 20 Euros unbranded

 

For sure LiFe will not work ... 4 in series make very close voltage to lead acid , so LiFe are perfect for replacing car battery ... 4 li-ion in series are 14.8V....
There's no need to complicate things they all cost the same ....

If I were doing this , and finances were tight , I'd just replace the two dead cells with One 18650 ,

This one is 8 Euros , it has a high capacity , so only one will have close to the capacity of two old cells ...
https://www.ebay.co.uk/sch/i.html?_...0.X18650+tabs+.TRS0&_nkw=18650+tabs+&_sacat=0

Really you should replace all eight they are cheaper for Eight , around 20 Euros unbranded

What about you just said about brands claiming high capacity cells of 3500 not being legit? That one is 3400 mAh. This ones are 2600mAh originally.

 

What about you just said about brands claiming high capacity cells of 3500 not being legit? That one is 3400 mAh. This ones are 2600mAh originally.

My post was very clear ... no cells have been made with over 3500mAh capacity
But you'll find many on eBay , cheap, with flashy wrappers like this ....

A trap for the ignorant , when tested they can have a capacity of about 1000mAh . I've dismantled some , removing the base and top cap revealed spot welding marks showing they had already been used , recycled from scrap laptop batteries , a big industry in China.

 

My post was very clear ... no cells have been made with over 3500mAh capacity
But you'll find many on eBay , cheap, with flashy wrappers like this ....

A trap for the ignorant , when tested they can have a capacity of about 1000mAh . I've dismantled some , removing the base and top cap revealed spot welding marks showing they had already been used , recycled from scrap laptop batteries , a big industry in China.

Ahh ok. I got it. I thought that over 2600mAh was possibly something that me scam trying to make money from people with less knowledge.

 

So, I'm about to order the cells but I still want to ask some questions.

@oz93666 , you're suggesting me those 3400mAh batteries to replace the 2 old Samsung 2600mAh I have? Do you think the 2 old 2600mAh might be around that value (3400mAh)?

Can it be measured?


Edited;
Another question I have.
Does this assembly have 2 different negative "sides" (can't remember the correct name)? Or are they isolated?

 

Who knows how to draw an equivalent circuit for a Li-ion cell? I found the attached schematic but I don't understand it:

Edited;
The link from ebay with the cells that were advised to me are not enough. They have only 7 cells left. I need 8 and I'm not sure these would be ok:

https://www.ebay.com/itm/Panasonic-...630761?hash=item4b300bdbe9:g:lvMAAOSwCPdZ6ZAP

Or this:

https://www.ebay.co.uk/itm/2Pcs-186...215458?hash=item2ce8f95562:g:B7UAAOSwOnBcr3FH

 

Just curious, as I recently purchased a couple of five-C cell packs rated at 5000mAh...

Are you saying these AREN'T 5000 mAH packs?

 

Just curious, as I recently purchased a couple of five-C cell packs rated at 5000mAh...

Are you saying these AREN'T 5000 mAH packs?

Oh no ...I should have been clear I was referring to 18650 lithium , that's 18mm diam ... 65mm high

 

So, I'm about to order the cells but I still want to ask some questions.

@oz93666 , you're suggesting me those 3400mAh batteries to replace the 2 old Samsung 2600mAh I have? Do you think the 2 old 2600mAh might be around that value (3400mAh)?

Can it be measured?

Who knows how to draw an equivalent circuit for a Li-ion cell? I found the attached schematic but I don't understand it:

Edited;
The link from ebay with the cells that were advised to me are not enough. They have only 7 cells left. I need 8 and I'm not sure these would be ok:

https://www.ebay.com/itm/Panasonic-...630761?hash=item4b300bdbe9:g:lvMAAOSwCPdZ6ZAP

Or this:

https://www.ebay.co.uk/itm/2Pcs-186...215458?hash=item2ce8f95562:g:B7UAAOSwOnBcr3FH

Does this assembly have 2 different negative "sides" (can't remember the correct name)? Or are they isolated?

This looks to be the same battery https://www.ebay.co.uk/itm/4Pcs-340...571863?hash=item4d944d3dd7:g:7AkAAOSw5QJc3tn-

this is a reliable brand and will give you 30% more capacity than a new laptop battery that only has 2600mA cells ...

The old cells after 5 years use will have less capacity , perhaps 2000mA .. so two old cell will have about the capacity of a new 3400mAhr ...

You could buy one of these first , and replace two damaged cells , and see if this will work ... I have no experience of this and computer softwear may prevent it , but at least you will have only bought 1 cell and not 8 , just doing this you should get 80% capacity , and it maybe a year or two before two more cells malfunction ....unknown territory...

 

@oz93666 the link you provided says 12£ for 4 cells, is that it? Or is it just one? I never understand these descriptions.

Another question, I've been told that there is the possibility that the charger controller gets blocked if the cells are not dessoldered and soldered back in a specific order. You know anything about that?

 

Yes ... 4 for 12 pounds and 18% off another 4 ...that's 22 pounds for eight

You are entering unknown territory , you may have damaged controller in disassembling ... could be other issues as you say ... no one can tell , for you to decide , either order just one and try that first , or go for eight ...

 

Yes ... 4 for 12 pounds and 18% off another 4 ...that's 22 pounds for eight

You are entering unknown territory , you may have damaged controller in disassembling ... could be other issues as you say ... no one can tell , for you to decide , either order just one and try that first , or go for eight ...

A friend of mine purchased this Liitokala batteries for his laptop. I think I'm going to risk to buy the pack of 8 and replace them all at once. I'll get better balance between them all and probably less risk of blocking the charger controller!

 

This looks to be the same battery https://www.ebay.co.uk/itm/4Pcs-340...571863?hash=item4d944d3dd7:g:7AkAAOSw5QJc3tn-

this is a reliable brand and will give you 30% more capacity than a new laptop battery that only has 2600mA cells ...

The old cells after 5 years use will have less capacity , perhaps 2000mA .. so two old cell will have about the capacity of a new 3400mAhr ...

You could buy one of these first , and replace two damaged cells , and see if this will work ... I have no experience of this and computer softwear may prevent it , but at least you will have only bought 1 cell and not 8 , just doing this you should get 80% capacity , and it maybe a year or two before two more cells malfunction ....unknown territory...

YCDC seems to brand and/or market a lot of things, including "high" capacity Li-ion 18650 cells:



Can you recommend them?

 

YCDC seems to brand and/or market a lot of things, including "high" capacity Li-ion 18650 cells:...Can you recommend them?

Yes ,,, recommend them for the garbage bin ...

Put "maximum capacity 18650" in google search ... I just did , it seems the absolute maximum capacity possible is 3600 ...But I've never seen one , only 3500 ...

And when a manufacturer can get away with such a lie , he knows the purchaser hasn't got a clue , so he uses the cheapest cell available 2200 , if your lucky .. if unlucky it could be a recycled cell under that nice new plastic wrapper