Why do laptop batteries disconnect their output?

[Simon]

I'd be curious to know how they find out given how well lithium burns.

They sent it to us, with a note basically saying "your shit (nearly|completely) burned down our clients house. WTF?".

Once the engineers get their hands on it, everything is inspected, and compared to a known original from the same production-run. The folds on Lithum-Ion casing are almost always intact. Stamping on the same.
The PCB might be burnt to a crisp, but most of the time you can still see the placement and approximate size of the chips that used to be on it. This catches at least 99% of the clone batteries.

Analysis of the LiIon casing would most likely reveal any replaced cells.

We also did forensic analysis in some extreme cases. Ever tried to dump NAND-flash that has been through a bombing?  I have..

Well if parts survive then yes I can understand that small differences from a genuine product can be noted.

[Simon]

On the one hand many people need protecting from themselves. i had to advise my boss that there was a reason his shitty device was being charged off a 4.2V power adapter and no he could not cut the wire off and put a USB plug on it.

but then it makes life hard for those that know what they are doing.

[Zero999]

Controller can be reset but not with free tools. Controller is password protected. Software will cost like a few batteries so repairing less than a handful of batteries is financially prohibiting. http://be2works.com/Home.aspx You would need to pay $200 to be able to reset BQ8030.

There's a demo version. Presumably only the paid version can reset the controller.

There's bound to be a kegen/crack floating around for said software, somewhere on the interwebs.

[wraper]

Controller can be reset but not with free tools. Controller is password protected. Software will cost like a few batteries so repairing less than a handful of batteries is financially prohibiting. http://be2works.com/Home.aspx You would need to pay $200 to be able to reset BQ8030.

There's a demo version. Presumably only the paid version can reset the controller.

There's bound to be a kegen/crack floating around for said software, somewhere on the interwebs.

There is no keygen possible. The software do not store any keys locally and communicates the server on every unlock.

[Sjokolade]

Also there is UBRT - but homepage is Russian  - https://translate.googleusercontent.com/translate_c?act=url&depth=1&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=auto&tl=en&u=http://ubrt.com.ua/&usg=ALkJrhjNzP8NNJaxfGz_MmqlurXKClN_Ng

[wraper]

Also there is UBRT - but homepage is Russian  - https://translate.googleusercontent.com/translate_c?act=url&depth=1&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=auto&tl=en&u=http://ubrt.com.ua/&usg=ALkJrhjNzP8NNJaxfGz_MmqlurXKClN_Ng

even more expensive. for BQ8030 need black_label -> $600 per year.

[Sjokolade]

Hehe yes it is - I see that the software was updated 2016-01-04   - do you know if BE2Works still is updated ?

[AmmoJammo]

Right now, I'm charging a laptop battery that was at about 0.15volts per cell...... 

I'd like to repack it, but there's not much point in doing that only to find that the protection circuit can't be reconnected!

[Audioguru]

Is your dead laptop battery a lithium one? If it is then it is extremely dangerous to charge it with a cheap charger that does not measure the battery voltage to find its very low voltage then begin charging at a very low current while monitoring the temperature of the battery to prevent a lithium fire. That is what a good lithium battery charger IC does. You can read about it at www.batteryuniversity.com .

[AmmoJammo]

Of course its lithium! and of course the charger wouldn't touch it!

SO I charged it as a nimh until the voltage was above 6volts, then pretended it was a 2 cell lipo, even though its a 4 cell.

All of this being done at the chargers minimum 100ma charge current.

[amyk]

Controller can be reset but not with free tools. Controller is password protected. Software will cost like a few batteries so repairing less than a handful of batteries is financially prohibiting. http://be2works.com/Home.aspx You would need to pay $200 to be able to reset BQ8030.

There's a demo version. Presumably only the paid version can reset the controller.

There's bound to be a kegen/crack floating around for said software, somewhere on the interwebs.

There is no keygen possible. The software do not store any keys locally and communicates the server on every unlock.

Interesting, could be a fun to crack it. However its homepage just got 404ed so I can not download the program.

A logic analyser would be enough, even one of those cheap Saleae-ish things. I did the same with some inkjet printer cartridge reset utilityservice.

Is your dead laptop battery a lithium one? If it is then it is extremely dangerous to charge it with a cheap charger that does not measure the battery voltage to find its very low voltage then begin charging at a very low current while monitoring the temperature of the battery to prevent a lithium fire. That is what a good lithium battery charger IC does. You can read about it at www.batteryuniversity.com .

See this thread for a good discussion of lion cell characteristics, including lots of debunking of "battery university"'s false claims:

https://www.eevblog.com/forum/projects/diagnosing-lithium-cells/

I used to work for one of the largest home-electronics manufacturers, and I dealt quite a bit with the batteries and charging, and I can explain how we reasoned when it came to protection circuitry.

1. Once a cell has been discharged beyond a certain point (varies between cells, even within the same chemistry), it's _bad_. The tolerances have been exceeded, and you're working outside of what the cell-manufacturer has tested and what the datasheet says. Ergo, as a manufacturer that takes responsibility, and actually care about our customer (and fears lawsuits), we have to make sure that the cell is not used again, as I could cause (in worst case) fires.
Dell, Fujitsu, etc know this all too well...
2. Replacing the cells in a pack is _way_ beyond what their intended use is, and to be honest, I wouldn't even do it myself..  Why? Am I chicken/boring/inept?  No, because, the likelyhood of me finding the _exact_ same cell to replace the failed ones is close to impossible. No, having the same formfactor and chemistry is not enough. The charge algorithm is tuned _exactly_ for the cell that it shipped with. And the cells that we shipped with were pretty darn good, so sourcing the same from a random internet-site is near impossible. Meaning, if you put a lesser specced cell in there, it will overcharge, over discharge, overheat, depending on how much the cells specs are off.
We easily spent a month _per product_, just fine-tuning the parameters. And that's not counting the hundreds of cells that spend a few months verifying the end-result.

And, frankly, if you do change the cells in a pack, and get it working, and it burns down your house, your insurance will find out.  We did forensics for things like that, as the insurance-companies liked to go after us (usually chargers though, but the occasional batteries as well). As we don't like getting blamed for things we didn't do (both us engineers, as well as our lawyers), it was important for us to figure out. Most of the time it comes down to "this wasn't ours", but we saw "poor repair jobs" as well, for parts that we simply didn't perform repairs on (packs and chargers are both such items, as it's more economical to trash them and send new ones).

That sounds like FUD. Did you by any chance learn from the "battery university" site too? Li-ion is one of the simplest chemistries to work with - just stay within the voltage and current limits. There is no special "charge algorithm".

You may find more interesting discussion here:

https://en.wikipedia.org/wiki/Talk%3ALithium-ion_battery#.22Battery_University.22

one of the most astonishing quotes of which is

It was long ago demonstrated that Buchmann had just trawled any information available from internet chat rooms and forums whether apparently reliable or just obvious rumour. Indeed myself and some work colleagues planted one such 'fact' for Buchmann to find and incorporate into his website. Indeed, he did just that, but although we deliberately chose something relatively harmless, an unintended consequence was that at least one major manufacturer built features into a line of products to protect them from the 'disadvantage' that we had conjured up.

Finally, don't forget that the Chinese have managed to release tons of product using bare user-replaceable 18650s (which would probably scare the crap out of you), but it's not like there are suddenly tons of extra fires. There have been some, but not as much as the scaremongers would like to have you believe... and I'd say lipo pouch cells make up the majority of fires since they're so much easier to damage.

Note that lithium-ion cells don't actually contain any significant amounts of metallic lithium, and most of the time the fire is the electrolyte burning; primary lithium cells are different, and do contain metallic lithium.

[stmdude]

That sounds like FUD. Did you by any chance learn from the "battery university" site too? Li-ion is one of the simplest chemistries to work with - just stay within the voltage and current limits. There is no special "charge algorithm".

No, professionals dealing with consumer electronics rarely learn from battery university.

First off, there is an "algorithm", and it's called "CC/CV", but, yes, it's very simple in ideal conditions.

Here's a few questions that you can think of while contemplating how easy it is to charge Lithium batteries:
1. Is the cell in your phone/laptop a 4.2,4.25 or 4.3V cell ?
2. Would you charge it the same at 0C, 20C, 40C and 60C temperatures?
3. At what current do you stop the CV phase of the charging?
4. At what point do you re-start charging a battery that's being used ?
5. Where does the IR of the battery come into play ?
6. Can you charge/discharge an older (as in cycles) battery as aggressive as you can a brand new one?
etc.

However, I see how you're thinking, and here's what would work..
Yes, you could have used any old CC/CV charger (set to the correct cell-voltage) to charge our batteries. You wouldn't get as much capacity out of them as we would (but, close). You would however, _not_ get as many cycles out of it as we did (80% capacity after 1000 cycles, guaranteed), nor would it charge as fast as we did, without danger.
The opposite is not true though. Putting a random cell into our device would lead to us charging it incorrectly. For instance, charging a cold battery too fast (bad), charging a room-temped fresh cell too slow (not dangerous), not backing off at at the correct (for the new cell) CV drop after charge-completion, causing excessive crystal buildup on the anode of the cell, etc.

Simply put, the charging in your laptop/phone is not a simple CC/CV "algorithm"