Hello.

I have an old (about 5 years old) Clevo laptop which battery is apparently with no charging capacity (about 28%).
I tried something I saw in the internet about keeping the battery for 15h in the freezer and then charge it completely. I left the battery for about 24h (because I forgot it there) and then I let it rest until it got back to ambient temperature and now I put it back in the laptop. But looks like charging capacity is the same.

So, now I'm thinking about 1 (or 2) of 2 things. 1 is to try to charge it with an intelligent charger (Technoline BC700) and perform a Discharge-Refresh cycle to try to revive the battery cells but I have no idea if this is a bad idea or not because charger is for NiCd and NiMH battery types and also because this is a 3V charger and battery is 12V if I'm not mistaken.

The other thing I want to try is to open the battery case, measure which cells are dead and replace them by new ones.

What are your advises?

 

I have no idea if this is a bad idea or not because charger is for NiCd and NiMH battery types

Then the charger is unsuitable for charging a lithium battery. Lithium based batteries need special charge/discharge control to avoid fire/explosion.
In the interest of safety, my advice is to buy a new battery.

 

1) Do you know the battery chemistry? Is it NiCd, NiMH, lithium? If not lithium, what size are the cells?
2) You cannot charge a 12V battery with a 3V charger.
3) Finding and replacing individual cells (assuming you can do that) will at best give a working battery with a very reduced life. Replace all the cells with fresh ones (if not lithium). If lithium, buy a new pack.

 

You shouldn't mix new and old cells within a battery so replace all the cells or none. I suspect, but don't know as a fact, that this is even more true for lithium than for other chemistries.

 

Well, I'll then consider to buy a full pack of cells. They will be cheaper than a battery itself. I've seen prices from 56€ up to 120€. It's ridiculous.

And when I measure the battery voltage across - and + I read about 16.09V and the battery is rated at 14.8V. I feel this is bad, no?

 

1) Do you know the battery chemistry? Is it NiCd, NiMH, lithium? If not lithium, what size are the cells?
2) You cannot charge a 12V battery with a 3V charger.
3) Finding and replacing individual cells (assuming you can do that) will at best give a working battery with a very reduced life. Replace all the cells with fresh ones (if not lithium). If lithium, buy a new pack.

The battery is Li-ion.

 

The battery is Li-ion.

Buy a new battery.

 

Buy a new battery.

Too much expensive. Not going to happen!

 

Too much expensive. Not going to happen!

Then spend a little time reading about what you want to do: https://batteryuniversity.com/

Good luck, but I am not holding my breath. BTW by "buy," I didn't mean it had to be in the same plastic housing. Although, there are surprise finds on eBay occasionally. I meant, buy new batteries assembled by someone who know the difference between Li-ion/LiPo and NiCd.

 

Too much expensive. Not going to happen!

If you think the battery is expensive, what are you going to do when a battery fire burns down the house? Li-Ion batteries are nothing to fool with. Do it right or don't do it at all.

 

Then spend a little time reading about what you want to do: https://batteryuniversity.com/

Good luck, but I am not holding my breath. BTW by "buy," I didn't mean it had to be in the same plastic housing. Although, there are surprise finds on eBay occasionally. I meant, buy new batteries assembled by someone who know the difference between Li-ion/LiPo and NiCd.

I will read about it and if I see I have no means of do it ng it by myself, I'll ask someone else more experienced to do it for me.

If you think the battery is expensive, what are you going to do when a battery fire burns down the house? Li-Ion batteries are nothing to fool with. Do it right or don't do it at all.

I'll be careful. If I find out I not capable of doing it safely I will ask someone to do it for me. No worries.

 

Too much expensive. Not going to happen!

Then snap it open , doing the least damage possible ... you'll probably find 18650s inside , just need to replace them , only buy recognised brands sony panasonic , it might cost just as much as a new laptop battery ....

This is how they make their money ... lap top batteries could last for 3000 cycles , but they charge to high , 4.2v per cell getting only 400 cycles .

 

I'm not sure how many cells the battery holds but if it's 6, it should be each cell at 2.467V. I'm measuring 16.09V which divided by 6 gives a voltage rating of 2.681V. Is this very bad? Why does the battery reads more voltage than the rated one? Is this on purpose or it's result of somehow damaged cells?

 

Does this battery have a label you could photograph and post here?

 

I'm not sure how many cells the battery holds but if it's 6, it should be each cell at 2.467V. I'm measuring 16.09V which divided by 6 gives a voltage rating of 2.681V. Is this very bad? Why does the battery reads more voltage than the rated one? Is this on purpose or it's result of somehow damaged cells?

Normally when these fail some cells are still usable ( In powerwalls) the voltage reading will not tell you what's going on ... break it open carefully , take out the cells test each one ... you can't use any of them in you laptop , but can in other applications ... I've broken open over 100 laptop batteries to recycle cells , more than half the cells are usable .... some are easy to break open ... most , you will destroy the plastic case in the process .... still worth a try

 

Does this battery have a label you could photograph and post here?

It has a label. I'm just not home to take a picture and post it. I'll do it later when I'm home.

Normally when these fail some cells are still usable ( In powerwalls) the voltage reading will not tell you what's going on ... break it open carefully , take out the cells test each one ... you can't use any of them in you laptop , but can in other applications ... I've broken open over 100 laptop batteries to recycle cells , more than half the cells are usable .... some are easy to break open ... most , you will destroy the plastic case in the process .... still worth a try

Yeah, probably I'll damage it quite a bit. I can't see any spots where I can stick a thin object to open it. It's everything really tight. But I'll give it a try when I get home. I'm at work.

 

Here is a picture of my laptop battery.

 

That's 4 batteries in series. 14.8 / 4 = 3.7 volts/cell nominal.
Minimum safe voltage would be around 3.0 * 4 = 12 volts
Maximum charge voltage would be 4.2 * 4 = 16.8 volts.

Do note that when you charge Li-ion batteries in series, you *need* a battery management system to be sure they are charged equally.

 

Well, they are actually 8 cells.
I managed to open the case. I damaged it quite a bit but I think ii is still usable. The case is heavily glued and no spots to press/push/whatever so that the case opens by itself.

I'm uploading a picture of the cells. I measured each cell individually and they all read 4.06V or 4.18V. None of the cells present a big difference in voltage. I'll upload here the picture as soon as it is ready.

The cells are Samsung ICR18650-26FU SDI 4C31

Here it is:

 

...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. See eBay ,,,, you could use 3500mAHr cells and get 30% more run time

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 posts 18 and 19