Tutorial: Laptop Battery Pack 18650 Extraction

[SilverFox]

Hello Varons666,

Welcome to CPF.

Let's back up and take another look at this.

If you have a cell with voltage V and capacity X and connect it in series with another similar cell, you end up with 2V and 1X capacity.
If you have a cell with voltage V and capacity X and connect in in parallel with another similar cell, you end up with 1V and 2X capacity.

When you connect cells in series, voltage increases but capacity stays the same.
When you connect cells in parallel, capacity increases but voltage stays the same.

Tom

 

[NeilP]

Out of interest how are you testing the mAh capacity ? what sort of tester? and discharge current?

 

[iteoschi]

Great guide! Is there a particular model of laptop that has this kind of batteries in its battery back?

 

[varons666]

Hello Varons666,

Welcome to CPF.

Let's back up and take another look at this.

If you have a cell with voltage V and capacity X and connect it in series with another similar cell, you end up with 2V and 1X capacity.
If you have a cell with voltage V and capacity X and connect in in parallel with another similar cell, you end up with 1V and 2X capacity.

When you connect cells in series, voltage increases but capacity stays the same.
When you connect cells in parallel, capacity increases but voltage stays the same.

Tom

Hi SilverFox,

Yes i understand how the parallel and series connection works but thats why im having a problem understanding because with
2 single cells in parallel im getting 1V and 1X and
2 single cells in series im getting 2V and 2X.

 

[varons666]

Out of interest how are you testing the mAh capacity ? what sort of tester? and discharge current?

Please see attached pic off multimeter , mine is more or less the same.

 

[zipplet]

How are you using this multimeter to test capacity?
Used alone, it cannot measure capacity - only voltage.

I read long ago that someone thought that using the current setting (amps scale) showed the "mAh" rating. Never, ever do this. If you are doing that all you are doing is shorting out the battery and measuring the "flash amps" - the current it will dump into a short circuit!

 

[varons666]

How are you using this multimeter to test capacity?
Used alone, it cannot measure capacity - only voltage.

I read long ago that someone thought that using the current setting (amps scale) showed the "mAh" rating. Never, ever do this. If you are doing that all you are doing is shorting out the battery and measuring the "flash amps" - the current it will dump into a short circuit!

ok thanks for the info, i used the same meter for every other batteries ranging from cellphone to gate motor batteries to AA and all tested fine.
if one single cell tested gives me +-6 "flash amps" , why when i connect 2 cells in parallel reading doesn't double, correct me if im wrong but the reading should double whether its correct or not and how does it double in series?

 

[SilverFox]

Hello Varons666,

I would guess that there is a limit built into your meter to keep it from destroying itself, or the cells may be unable to perform due to age or previous use.

To properly measure capacity you need to load the cell with a known load (say 500 mA) and time how long it takes to get to the low voltage shut off (say 2.8 volts). This gives you load and time and you end up with mAh or Ah.

Li-Ion cells are capable of very high flash current impulses. Going from memory something like 6 - 8C. That means a healthy 2400 mAh cell could possibly deliver 19200 mA under a flash condition.

Tom

 

[varons666]

Hello Varons666,

I would guess that there is a limit built into your meter to keep it from destroying itself, or the cells may be unable to perform due to age or previous use.

To properly measure capacity you need to load the cell with a known load (say 500 mA) and time how long it takes to get to the low voltage shut off (say 2.8 volts). This gives you load and time and you end up with mAh or Ah.

Li-Ion cells are capable of very high flash current impulses. Going from memory something like 6 - 8C. That means a healthy 2400 mAh cell could possibly deliver 19200 mA under a flash condition.

Tom

i dont think its a builtin limit on the meter because in series i get the full reading.

ok so i charged up a single battery upto 4.20v and i put 200mA load for 1 hour and the voltage dropped to 3.94v, how would i calculate the mAh? (lol only tested for 1 hour since thats how long our load shedding lasted)

 

[SilverFox]

Hello Varons666,

200 mA for 1 hour gives you 200 mAh. From here we have to speculate. IF your voltage rebounded, after taking the load off, to around 4.0 volts, we can speculate that you have about 80% of your total capacity left in the cell. If we take 200 and divide it by the speculated 20% used we end up with a speculated capacity of 1000 mAh for the cell.

All this speculation is not very accurate but now you can run your test again and plan for having the load connected for 5 hours, or more.

Speculation can be avoided by leaving the load connected until the voltage drops to something like 2.8 volts while keeping track of the time. Then you will have the actual capacity.

Tom

 

[ID01]

First time poster long time lurker yadayada, did my first reclaim battery task on a Dell 9 cell 87 WH 11.1V laptop battery and produced about 9 of these LGABD11865 batteries.

The only source that appears some what accurate is here: http://www.alibaba.com/product-deta...305570.html?spm=a2700.7724838.35.1.LwrwY9&s=p

Any suggestion on what to do with these?

What I was planning on doing was to use 6 of these in one of these:

http://www.aliexpress.com/item/Univ...ower-Bank-Battery-Charger-Box/1938749138.html

to power a surface pro 3.

Overall, opening the packaging was a bit of a hassle but nothing all that tricky, I ordered a cheapo multi-meter a few posts ahead of this one but it has not arrived yet. All the test I did was to put it into a CREE portable 18650 LED flash light, and all of them light up brilliantly.

Are there any safety concern with this specific battery for my specific use? Any trick that I should use for real testing before charging them at all? Should I buy a different charger for those?

Thanks

 

[USSR]

if the description on alibaba is correct then these are 4.35v cells . and most of these battery banks chare till 4.2 (and in my experiment i lost 200mah if a 4.3 volts battery was charged to 4.2 )..

also this case is extremely costly .. i have ordered below one and waiting or shipment to arrive .. will take couple of weeks. 5x with lcd models are available at 7 USD max with free shiping that could take at least 2-3 weeks to arrive.


http://www.aliexpress.com/snapshot/6763920470.html?orderId=68039039964750


use multimeter . any cell having voltage above 2.9-3 volts is a nice candidate . charge it and discharge it to 3 volts and monitor it for heat .. if it passes this test and gives sufficient run time then its ok ..
any cell with voltgae below 2 .. i would throw it .. though it could be resurected ..

First time poster long time lurker yadayada, did my first reclaim battery task on a Dell 9 cell 87 WH 11.1V laptop battery and produced about 9 of these LGABD11865 batteries.

The only source that appears some what accurate is here: http://www.alibaba.com/product-deta...305570.html?spm=a2700.7724838.35.1.LwrwY9&s=p

Any suggestion on what to do with these?

What I was planning on doing was to use 6 of these in one of these:

http://www.aliexpress.com/item/Univ...ower-Bank-Battery-Charger-Box/1938749138.html

to power a surface pro 3.

Overall, opening the packaging was a bit of a hassle but nothing all that tricky, I ordered a cheapo multi-meter a few posts ahead of this one but it has not arrived yet. All the test I did was to put it into a CREE portable 18650 LED flash light, and all of them light up brilliantly.

Are there any safety concern with this specific battery for my specific use? Any trick that I should use for real testing before charging them at all? Should I buy a different charger for those?

Thanks

 

[ID01]

The reason I ordered this specific one is for the 12V output to support notebook recharging on the go. Which is something I would like to experiment on. Even if it end up not working out it would still work as a fast 5V charger considering the Ampage it is able to put out according to this review here:

http://lygte-info.dk/review/Review USB battery box 6x18650 Qidian UK.html

I will probably wait for the DMM to come before trying to charge it or play with it in anyways in that case.

 

[markr6]

Check these out! Old Sanyo UR18650Y 2000mAh pulled from my Sony Viao manufactured ~2008. Laptop was used pretty hard but also sat around a lot without use.

I finally got to test them with my Opus C3100 v2.2 charger. These are the results after a charge/discharge.

Still about 85% capacity which is what I would expect after the use and 7+ years. But not something I really have a need for. Internal resistance ranged from 105 to 125.

 

[WarRaven]

Nice MarkR6.

I pulled some ancient UR18650V AN US18650GR yesterday myself.
These are old, 2007 an 2005.

I have to lsd check, dum charger.

 

[xzel87]

Nice pulls mark, I have similar cells I pulled before but unfortunately they were pretty useless in terms of capacity. The okay ones became increasingly warmer the more I charged them so finally disposed of them. If you read my previous posts, of all the recovered battery I've disposed all except for 6 cells (from the same pack, green coloured Sony cells) due to safety concerns. For those 6 Sony cells, 4 is used to power my 1x18650 light I use as a nightlight so normally cycle between all 4 in 2 weeks or so running continuously and the remaining 2 is for my headlamp (for night reading).

 

[xzel87]

Double posted.

 

[etc]

Check these out! Old Sanyo UR18650Y 2000mAh pulled from my Sony Viao manufactured ~2008. Laptop was used pretty hard but also sat around a lot without use.

I finally got to test them with my Opus C3100 v2.2 charger. These are the results after a charge/discharge.

Still about 85% capacity which is what I would expect after the use and 7+ years. But not something I really have a need for. Internal resistance ranged from 105 to 125.

That's a nice charger, and not that expensive.

 

[markr6]

That's a nice charger, and not that expensive.

I'm impressed. Even though I got it for about $32, I would have no problem paying up to $50 or so. I haven't touched my other chargers since I got it (at least for Li-Ion)

 

[xzel87]

Thats my go to charger now as well...even for nimh...feel bad not using my c9000 for nimh hahaha