Jumper = Idot, or "How I killed a $80 3-cell battery"

I never used the 3-cell battery that came with my Z33 a lot. It only ever lasted for ~2.5-3 hours, and 9 cell pulls 6-7. I don't mind the weight, so 9-cell it is.

Last week the 9-cell ran out while I was in class (shame on me for not charging it for a couple days). I pulled out the 3-cell, which was charged to ~40%, and finished up the lecture just as the battery ran out. When I got home, I put in the 9-cell to charge for the next day's classes...

Fast forward a week. I see the 3-cell battery sitting on my desk, and realize I never re-charged it. I put it in the laptop... in NHC the voltage is 8000mV (vs 11.1V specified). No charge rate is listed, and neither is a 'current capacity'. The voltage is slowly dropping over time.

Yup, it's dead. The SMBus isn't asking the charger for any juice. If I had a $25,000 battery analyzer I might be able to reset it, but nope.

Now the question is, do I bother buying another, or no.... I don't think I will, the 9-cell hasn't worn at all in the last 8 months. Maybe when I get to CA and I'm making some $$$ I'll drop the coin for a whole new set. The Z35 6-cell and 9-cells are backwards compatible with the Z33, so I'm not concerned about unavailability in the near future.

Important note: I don't blame Asus or my laptop for this at all. The undercharge protection is a standard feature on Lithium Ion cells, and for very good safety reasons. This is simply a case of busy, end-of-the-semester forgetfulness biting me in the ass,

Also, let this be a warning to the people with the 4-cell battery on the U1 - don't let it sit around with low/no charge, because the small capacity batteries self-discharge at a much faster rate then their larger brethren.

Sigh. Back to writing final reports and papers...

 

would the battery callibration do anything?

 

If a Lithium Ion battery drops too low a period of time it becomes dangerous to recharge (shorts can form inside the battery). To protect against this there are two voltages that the system/charger watches for. The first and higher voltage is where the system shuts down. The second and lower voltage (safety point) is where recharging is no longer allowed. If you leave a "empty" battery sitting long enough it will eventually fall below the safety voltage and not be rechargeable by normal chargers. Shorts eventually form in the battery and recharging would cause over heating, melting, and even explosion/fire.

http://www.batteryuniversity.com/partone-12.htm

If you're not going to use a Lithium Ion battery for a long time, store it with about 40% charge in a cool place.

http://www.batteryuniversity.com/parttwo-34.htm

And no, calibration won't help at this point. Sorry to hear about your accident Jumper.

 

Yeah, I'm aware of all that. It's more of an issue with smaller batteries like this one then the larger 6 and 9 cells. I just thought I'd toss it out here as a warning, especially for anyone with the U1 4-cell.

Sh*t happens... *shrug*

 

In your case I would actually attempt to take it apart and replace the cells with nimh cells you can buy at a drug store.


Because there are only 3 cells I dont think it will be a difficult operation.It is probably a minor soldering project.

 

Uhm... No.

SMBus batteries work by moving the "smart" part of the battery from the charger to the battery - the chip in the battery basically asks the computer "please charge me with x current and y voltage". I have a Li-Ion SMBus. Giving it Nimh cells would probably not be the smartest thing in the world.

 

It would work 100% fine.

What youre calling the 'battery' is the case.

The cells are 100% just aa battery cells. absolutely dumb.

Many guides on this on the internet. The difficult part is that that cells are connected with a peice of metal normally soldered.

and the plastic case is normally glued shut

 

NiMH and Li-ion have different charge patterns and voltages.

 

um they have different voltage but so small a difference it wouldnt matter

Been done so many times.

You can also order the li ion cells but the reason i didnt suggest that is they are expensive and you can ruin the battery trying to replace them

I suggest opening it up to see if you can do it, and then if you can spend 10$ or less replacing it with nimh batteries.

 

You must be talking about something else. A normal Li-Ion cell has a voltage of about 3.6V and charge voltage of around 4.2V. Could you please link me these replacement/swap articles?

 

Stamer, I don't think you understand how a modern laptop battery works.

There is an entire computer in the battery that manages the charging and discharging of the cells. It keeps track of all of the wonderful charge state, rate, and wear level information you see in NHC - the battery itself does all that. Once that computer decides the battery can't be recharged, it's all over with.

I've seen the swap guides, but they were all for old batteries, 3-5 years ago, before the newer SMBus systems because prevalent. Without specialized equipment there is no way to reset the SMBus once it has decided not to let the cells be charged.

If you want to blow your laptop/house/car/bookbag up be my guest, but I'll pass.

 

Oh no, its definitely you who are mistaken.

Once you have new cells in the computer will let them recharge. absolutely positively. What sort of permanent storage do you think is in the smbus voltage sensor?

because they are not hte orignal types of cells it will think they are either worn already or overcharged. It wont charge them at the right rate for nimh which someone said earlier. Will work absolutely though.

I also suggested you replace them with cells that wont blow up as well, lower capacity consumer rechargeable batteries. This is just because if you ordered the wrong kind of li ion cell you could mess it up and i didnt want to explain that out.


I could even show you a battery i did this on however that project failed. Not because the cells werent interchangeable but because the 8th cell was soldered in a permanent way necessitating breaking one of the sensors it used. The battery had to have one dead cell which made it deteriorate the other cells very fast.
I couldnt tell you your battery was any different but i could say its worth a try with only 3 cells in the battery.

heres a google at random
http://www.fonerbooks.com/laptop_3.htm

 

Ohhh you are definitely right. li ion cells actually come in 3 voltages.

there are guides to replacing them on the internet go to google and type replacing cells in notebook battery.

Youre right though nimh cells wont work or would be quite complicated to make work.

The thing here is each cell has a different voltage lets just call it twice a nimh cell. But the nimh cells just have more of the cells in serial the li ion cells more in parrallel because the output is the same. You would have to custom solder a connecter to make the cells the same voltage.

It is not a garden variety project.

In this case its so difficult actually because there are only 3 cells. No way to put 3 x 1.6 4.8 turn it into what has to be either 3.2 or 6.4 voltage . would need a electronic peice. or fit another cell into the case. Or invest in the correct cells.



there is a whole cottage industry of replacing the cells in notebook batteries and selling them as refurbished. It takes no special tools maybe intermediate soldering. Ebay is filled with them as are computer magazines. Todays batteries

 

Where do you think that the 'Manufacturer', 'Serial Number', 'Designed Capacity', 'Current Capacity', and all of the other battery information come from? It's all stored on a chip in the battery. SMBus is not just a voltage sensor.

The link you posted was to a NiMH battery.

 

Heh, the reason why these Li-Ion battery packs have these chips is to make sure some idiot DOESN'T do that and blow himself up to kingdom come... these aren't "dumb" lead-acid batteries where you check for a float voltage. Nor are they like the old NiMH battery packs from the old days where the charger was responsible for the proper charging of the cells.

Fact of the matter is, Li-Ion is that much more fragile and dangerous, but holds more charge and can be made safe WITH PROPER MONITORING CIRCUITRY. This is where the smart chip comes into play, since it "remembers" things and can tell the charger if it is safe to charge or not.

If he thinks it's such a good idea to replace Li-Ion with NiMH or start swapping the insides of the battery around, he'll eventually do it himself and find out the hard way.

 

Id like to make a sticky for people who want me to link them to google. But google is the same for me as for them. Youd like me to type in the question and then click on the links for you.... but why dont you do it yourself?

http://www.google.com/search?client...n&q=replacing+li+ion+cells&btnG=Google+Search

http://www.electronics-lab.com/articles/Li_Ion_reconstruct/index_1.html

Definitely not what I was thinking. There must have been a battery that used aa cells that were li ion but its not the same as these cells. Like for instance in a camera battery pack.

Defintiely possible but getting the cells is not worth it.

 

Did you just go to school for four years for engineering? I think I trust the combination of my Chemistry/Electrical Science classes more then some sketchy website. Amazingly enough I did research the issue, only I looked for reputable industry sources. Conclusion - without knowing about Asus' specific implementation of SMBus, it's probably next to impossible to re-cell a battery safely and with reasonable certainty that it will work afterwards.

The funny thing is that I've found 7-8 sites that have that same exact tutorial repeated verbatim, none of which have actually tried it.

Newer SMBus batteries query the computer for an activation code when they are first plugged in. No code, no charging. That code is stored in the battery and maintained by using a small amount of power from the cells in the battery. The instant you remove the old cells that memory is blanked, and the whole battery is useless after that.

 

come on rocket scientist. Those are on a chip all that data does not change.
that would be a rom chip.

The sensor would send current capacity etc to your computer> but what medium do you think it would record on when the electricity had been removed? i mean do you think they put a flash drive in there? a hard drive?

where do you think the battery records this " cell went too low we wont ever charge again even if new cells are put in" message?

it makes sense that you trust your experience more than what is on the internet jumper
but i dont because i saw jumper post on nbr that means entirely nothing to me that is entirely unreliable information to me

 

It's a few cells of regular old RAM.... A few bytes. Any CMOS based integrated circuit can have registers like that. When you remove the old cells, the chip looses power, the contents of this RAM are lost, and the battery can no longer talk to the computer.

There are ways around it by connecting an alternate voltage source to the SMBus while doing the cell replacement, but every bit of complexity is another place to mess up.

However, it's a moot point anyway. The was Asus designed the battery pack, there is no real way to get it open without physically destroying it beyond being able to install new cells. I wanted to see what was inside before I recycled it, so I tried... No way it's happening.

 

Umm... if it's still less than 1 year from DOP for the battery, try warranty replacement?

 

Actually I am a rocket scientist and Jumper is right.