Is it worth buying old laptop battery`s for the 18650 batery`s inside.

[TinderBox (UK)]

I saw an 8 cell supposed according to the model number 2400mah sanyo cells inside, for £5.99 free shipping, but the seller says the battery has not been tested so it might be dead, it looks like he strips notebooks and sells the parts to me.

Is it worth the risk?

Thanks

John.

EDIT : after capacity testing at .2c only approx 2000mah 83% is available from the 2400mah cells.

 

[Changchung]

I do it a lot of times, for that price I will pull the trigger...


Sent from my phone with camera with flash and internet on it...

 

[TinderBox (UK)]

Just bought it, it`s an "Acer Aspire 9300 4UR18650-F Battery. 14.8V 4800mAh" according to the model number it has sanyo cells, ohh well more money down the drain maybe

John.

I do it a lot of times, for that price I will pull the trigger...


Sent from my phone with camera with flash and internet on it...

 

[Changchung]

Just bought it, it`s an "Acer Aspire 9300 4UR18650-F Battery. 14.8V 4800mAh" according to the model number it has sanyo cells, ohh well more money down the drain maybe

John.

I am almost sure that all the batteries are good... Let us know...


Sent from my phone with camera with flash and internet on it...

 

[bluecrow76]

Some of the best 18650 cells I have (besides my AW cells) are ones I've harvested from quality battery packs.

 

[TinderBox (UK)]

I noticed after i bought the battery, it actually has "4UR18650-F" in the model number.

EDIT : So how is is best to open a notebook battery, any tips?

John.

 

[Al_D]

I noticed after i bought the battery, it actually has "4UR18650-F" in the model number.

EDIT : So how is is best to open a notebook battery, any tips?

John.

Carefully. Most are held together with plastic tabs but, worse case, they're glued or ultrasonically welded.
Removing the spot welded contacts on the cells is the hardest part, commonly. I found using strong but precise needle nose pliers utilizing a rolling motion worked well for popping the (usually 4) spot welds.

Be careful removing insulation or adhesive tape/glues-- you want to keep the cell wrappings undamaged.

If the battery pack is bad chances are it will only be the regulation PCB or a handful of cells that are the culprit.

Often cells will have varying 'life' remaining due to how the cells are wired in the battery.

I suggest checking voltages after you've successfully removed the cells and group them.
Toss any that are dangerously below minimum voltages as they'll be the most likely to have serious issues when you try to charge them.
For the rest, charge them under great scrutiny. Cleaning up a ruptured cells is not a fun ordeal.

 

[127.0.0.1]

Carefully. Most are held together with plastic tabs but, worse case, they're glued or ultrasonically welded.
Removing the spot welded contacts on the cells is the hardest part, commonly. I found using strong but precise needle nose pliers utilizing a rolling motion worked well for popping the (usually 4) spot welds.

Be careful removing insulation or adhesive tape/glues-- you want to keep the cell wrappings undamaged.

If the battery pack is bad chances are it will only be the regulation PCB or a handful of cells that are the culprit.

Often cells will have varying 'life' remaining due to how the cells are wired in the battery.

I suggest checking voltages after you've successfully removed the cells and group them.
Toss any that are dangerously below minimum voltages as they'll be the most likely to have serious issues when you try to charge them.
For the rest, charge them under great scrutiny. Cleaning up a ruptured cells is not a fun ordeal.

wear safety goggles or glasses when cracking open battery packs!

 

[TinderBox (UK)]

Great info guys, so below what voltage should i dump an out of pack cell, is any cell below 3volts a reject?

I have 4 lights that take 18650, two of them are the old VB-16 3watt , I bought one of thouse usb charger boxes from ebay this one takes 1-4 18650 battery`s and they are cheap at only about £5 delivered, I have used it to charge up my Galaxy S3 a few times.

John.

 

[Shadowww]

You should reject cells not based on voltage (although <2V cells should be dumped in most scenarios), but based on their remaining capacity, internal resistance and self-discharge. You'd need a good hobby charger to test all 3 of these (but cheap hobby chargers can still measure capacity and self-discharge, just not internal resistance).

 

[TinderBox (UK)]

Hi.

At what voltage should i stop the discharge when i am trying to check the capacity of these old 18650 battery`s

I have a Thunder AC6 charge, is this suitable to ascertain the capacity of these battery`s

Thanks

John

 

[Shadowww]

Yup, it's suitable. Discharge them down to 3V, that's recommended cut-off voltage for most Li-Ion batteries (some are 2.5V, but those are rare)

 

[TinderBox (UK)]

What discharge rate should i use to determin the cell capacity of the 2400mah cells

Thanks

John.

Yup, it's suitable. Discharge them down to 3V, that's recommended cut-off voltage for most Li-Ion batteries (some are 2.5V, but those are rare)

 

[Shadowww]

0.2C (which is approx. 0.5A for 2400mAh batteries).

 

[TinderBox (UK)]

Great, just got to wait for the battery to arrive and i can play.

Thanks

John.

0.2C (which is approx. 0.5A for 2400mAh batteries).

 

[lwknight]

Most laptop batteries that I have messed with have a thin plastic stick on cover. You peel that off and just cut the straps and sides with dikes. Pretty easy really. Good needle nose pliers are work well for stripping the welded tabs. You will still have the little contact nubs but they dont hurt anything. I guess if it mattered you could sand them off too.

 

[TinderBox (UK)]

This is the one i won, i see what you mean about the big label, still wating for it to be delivered.

John.

 

[Al_D]

This is the one i won, i see what you mean about the big label, still wating for it to be delivered.

John.

That'll pry right open, without a problem.

 

[TinderBox (UK)]

Well i got my battery, it was easy to open, cells were flat/empty see out of pack voltage below, now to do a charge and discharge capacity test, while keeping an eye on the temprature.

nice red/pink cells with KJBFK35 063500

2.62v, 2.81v, 2.81v, 2.84v, 2.84v, 2.82v, 2.82v, 2.62v

John.

 

[Changchung]

Well i got my battery, it was easy to open, cells were flat/empty see out of pack voltage below, now to do a charge and discharge capacity test, while keeping an eye on the temprature.

nice red/pink cells with KJBFK35 063500

2.62v, 2.81v, 2.81v, 2.84v, 2.84v, 2.82v, 2.82v, 2.62v

John.

Nice, I am almost sure what all your batteries are good...