The Li-Ion battery in my IBM Thinkpad X31 laptop has been getting a bit long in the tooth. Rated at a 4.4 AH capacity new, /proc/acpi/battery/BAT0/info told me that it was only holding 1.8 AH now that it was a few years old. (This is normal for Li-Ion batteries, which degrade over time, even without multiple charge-discharge cycles.)
A brand new IBM (or Lenovo now) battery costs over a hundred dollars, but by shopping around I was able to find a "compatible" battery for as low as $50. It was only rated at 4.4AH, but that is relatively close to the 2nd generation 4.8AH batteries that IBM/Lenovo sell for twice as much. I started to wonder if it might be cheaper to buy OEM li-ion cells and simply replace the cells (keeping the case, and charge/discharge electronics). The first step would be to determine what type of Li-Ion cells I'd need to buy, so I decided to open up my old battery.
As you can see, the standard X31 battery has six cells, in three parallel groups of 2. Cells are nominally 3.6volts, so this adds up to 3 x 3.6 or 10.8 volts. In the photo I have removed the shrink wrapped packaging from one cell to view the markings. Note the relatively complicated PCB along the back side of the cells that handles charging and discharging. If you zoom into the photo, you can see that the controller PCB is connected to each end of every pair of cells (orange and black wires to the far ends, silver metal tab connections to the middle two). This allows the controller to charge each parallel pair of cells at a different rate. The controller PCB is also connected to a thermocouple that is resting between the two middle cells. This gives the controller a temperature reading on the cells during charging and discharging. If the PCB detects that the temperature is too high, it can lower the charging rate, or shut down the power draw (and laptop). Also note the heat fuse (small white block in series with the power line between the two leftmost cells) that is designed to open the circuit if the charge/discharge controller for some reason fails to maintain a safe temperature. All of these safeguards are designed to keep your laptop battery from igniting, and will be very important to maintain in any "re-manufactured" batteries.
I actually determined what type of li-ion cells were used by measuring them and then looking for li-ion cells of a similar size. They are about 2.5" high by 11/16" diameter, or very close to the 64.9mm x 18.3m diameter size of a 18650 style cell that I found on www.batteryspace.com.
My battery is rated at 4.4AH, or 4400mAH. As it has three sets of parallel cells, each set of two cells must have a 4400mAH capacity (because they are in series, you add the voltage, not the amperage), so each cell must have a 2200mAH capacity.
From a mAH per dollar standpoint, batteryspace.com's 2000mAH cells are the best value, but I decided that since the total cost difference was only six dollars, I could afford purchasing the 2200mAH cells. These are slightly lower than the 2400 mAH capacity of the newcells that Ibm/Lenovo now use, and I'll end up with a 4.4AH battery (just like the original part number, before IBM/Lenovo upgraded it to 4.8AH).
Just the cells cost $34.20, but I chose to purchase them with solder tabs attached (an extra $1.50) because I figure the people at batteryspace.com are better than me at attaching tabs, plus having extra tabs to work with (those that come on the cells, plus those I salvage from the original cells) will make my life easier. (Besides, the $7 of shipping is the largest extra expense….if the 2600mAH cells weren't almost twice as expensive as the 2200mAH cells I'd have gotten them just get a 5.2AH capacity battery!) The total cost was $43.42. A week later my batteries arrived. (Thanks UPS!)
Important safety note!
You should never replace li-ion cells with cells that have a lower capacity rating, or charge/discharge rate rating. The electronics in laptop batteries are programmed to prevent the cells from overheating and catching fire, and do a very good job as long as the replacement cells in the battery are of equal or higher rating than the original cells.
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Jay, thanks so much for the Info! I had never even thought of that!
I bought an old panasonic toughbook for my daughter from ebay, and of course, the battery was dead. cost of a replacment on ebay: about a hundred bucks. a quick google search for the cells found them at about 3.50 each. total cost for 9 cells plus shipping:$45.26
you just saved me at least 50 bucks!
Thanks again! –
Great stuff!
Thanks for mentioning explosive batteries. They really stink too.
Its pretty easy to injure the batteries even if you dont explode them with the soldering iron. (= less capacity)
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Warning, from the voice of experience: in addition to taking care to not overheat cells while soldering, also take care to not physically damage or deform the cells such as dent, ding or put undue pressure on them when re-assembling. Any physical damage can lead to an internal short and if the battery has sufficient charge, it will overheat and leak, smoke and/or explode, in that sequence.
BEWARE !!! , not all notebook battery can be refill like this way , some new smart notebook battery got a flash chip inside , when u took off the battery the chip is automatic erase , so you never can recharge your battery , even you change the new cell inside, u only can refill some old nb battery like 5 or 6 year old notebook !
How to know if flash chip is present on battery?
BTW Very nice howto
Plesae could someone tell me where I can purchase these batteries from!?!? The ones that go inside the battery pack.
I bought the batteries (li-ion cells) from http://www.batteryspace.com (it’s listed on the first page of the post.) Others sell them too, if you do a search for “18650 li-ion” on froogle.com plenty of dealers come up.
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I got IBM R32 LAPTOP please advise how to open the battery pack and replace with an OEM cells..? Do you have some pics
Much appreciated. Best regards
The R batteries should be very similar to the X batteries. I used a Cell Phone opening tool (Green plastic pry bar) to gradually crack open the battery at the seam and “un-snap” each of the clip in snaps that hold the two halfs together.
I followed your lead and rebuilt my A20m’s battery pack (original IBM # 02K6618). I bought my cells from batteryspace and got the 2600 mAh cells. Worked great! Now, about resetting that flash chip…my pack has an AS358D flash chip. I’ve spent a lot of time looking on the web for info on reflashing the chip, and have only found one thing: “Smart Battery Workshop,” a program that claims it can read and reflash the chip. Problem: another company bought the program’s creators, and now only rebuilds batteries for you. The program was apparently well copy-protected and I can’t find a hacked copy. If anyone can find a way to reset the flash chip, we’ll all be good-to-go.
For those of you not as technicly inclined as most on this forum, and who consider refilling your batteries as a cheaper means of getting your old laptop back in order, this comment is for you. Beware refill services like Batteryrefill.com or the like who promise a “quick turnaround.” If you are the type who needs your laptop for flexibility and needs it often, you are better off buying a new battery rather than wait the 2+ months some of these services take to work on your batter.
Thanks for the great tutorial!
Would you have any advice on how to pry the battery case apart?
Lutz:
I used some plastic tools made for prying cell phones apart. It takes a bit of technique to do it without damaging the plastic. I basically get one of the two tools in place, and then slide it along while using the other tool to keep pressure on the crack.
I used one very much like the following: http://www.apscell.com/prytoolb.html
Jay
I replaced the 6 Li-ion cells in the pack for my IBM T40. I get great prices and service from allbattery.com. I guess I need to reflash the chip in the pack. The batteries measure 3.6 volts, but they won’t charge in the laptop. It sees the battery pack and says it’s 1% charged, but won’t charge.
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I thought doing this stuff to my X21 battery. The only problem is: I can’t even start because I’m unable to OPEN the battery case. It’s a tight seal. Did you find this in the X31 battery too?
Eddy:
Yes, the two halves are sealed together very well. I used some plastic “cell phone opening” tools to gradually pry the sides apart, working the crack along as I went.
Jay
>I have a curiosity question
> which I wonder if you have ever considered or heard of
> elsewhere: Substituting lower cost NiMH cells for the Li-
> Ion cells.
While NiMH cells can be used in a battery, you should NEVER replace LiIon cells with NiMH cells. The reason for this is that the charging electronics in the battery are designed for LiIon cells, which are able to receive a much faster charge than the NiMH cells. If you tried to charge NiMH cells with a LiIon charging circuit, they would likely burst, burn, or even explode! Now, if you were able to find a battery pack that was similar to your notebooks (perhaps for an earlier model notebook in the same series that used NiMH batteries, you could replace the (LiIon) charging circuit with the NiMH charging circuit, and then you could use NiNM batteries.
Hi Jay,
which OS and/or which tool do you use to check the capacity?
Greetings from Munich/Germany
Chris
I’m using Linux (with acpi enabled) to get the detailed battery information.
cat /proc/acpi/battery/BAT0/info
Jay
>Hi Jay,
>which OS and/or which tool do you use >to check the capacity?
I found a way to reset the full-charge capacity for Power Manager on WinXP. Follow instructions given by Jay, but perform a “battery gauge reset” between your full discharge/charge cycles.
An additional tip for this to work well is to fully discharge with all timers off, and then fully charge with the thinkpad switched off.
The results are:
– 1st reset: 8.76 to 12.73Wh
– 2nd reset: 12.73 to 13.33Wh (didn’t do something right????)
– 3rd reset: 13.33 to 18.62Wh
– 4th reset: 18.62 to 27.45Wh
– 5th reset: 27.45 to 37.23Wh
– 6th reset: 37.23 to 45.72Wh
– 7th reset: 45.72 to 52.99Wh??
Now my R51e runs for almost 4.5hrs before reaching 1% on “max battery life” settings! (I replaced the cells with 2600mAh!)
Can we do this with lithium polymer?
Robert:
Lithium Polymer cells are basically LiIon cells that are more flexible, so should work just fine for this type of application.
Jay, or anyone, do you know if there is a flash chip set in my Toshiba Satellite M45 S3553? thanks
Also tips for opening up the battery pack would be nice, thanks
hello! and do I can use the NiMH cells and just recharge it in outside recharger not in notebook?
QAD417: I do NOT recommend using NiMH batteries to replace Li-Ion cells. If you did, you could not use the built in laptop Li-Ion charging circuit. You would instead need to use a NiMH charger (either outside the notebook as you suggested, or somehow built into the battery pack). [Of course, if the original battery pack used NiMH cells, you could replace them with NiMH cells.]
My battery at the moment has 4 3.7v (totaling 14.8) cells in series. There is space for 8 cells (there is a large capacity model that uses the same battery case). Could I create 4 banks (in series) of 2 cells (in parallel), still giving 14.8v but doubling the capacity. Will the charging circuit be able to cope? Will the battery me more likely to overheat (I guess the current drawn from each cell will be less so it will be cooler)?
Nathan:
Technically, every cell should be controlled independently. (That is why your existing charging circuit should have a wire that goes to the connections between each cell to the next, so that it can control the charging current to each cell independently.)
However, as long as you stick with a matched set of cells, I expect that you should be 100% safe if you “doubled up” each cell (in parallel). To the charging circuit, it would look like each of it’s individual cells just got more capacity. You are also correct that the power draw from each cell would be halved so the temperature should be cooler. (I expect that your battery would also take twice as long to charge.)
You are indeed lucky to have a battery with extra empty space in it, what model/brand is your laptop?
Jay
Thanks for the quick reply? Now the battery is apart I can see there is only one wire to each pair of cells (actually to the connecter between the two). The laptop is an IPC Multimedia Desknote E (though I have seen it alternatively branded). The battery is an EM-G320L1 (I think made by Elitegroup Computing Systems).
How do you open the plastic case of the Compaq Presario R3000 laptop battery, a 14.8V 6600mAH?
Do I have to cut it open?
Are there any higher capacity cells?
Thanks
I did a restore of my X31 battery and have soldered everything up correctly (looking at your pictures and ones I took before removing old cells) and the battery wont charge.
Watching the temps under linux show they stay normal but the charge/discharge rate doesn’t change. I left it hooked up for 20 minutes and nothing changes…should I just leave it longer?
Adam: It took me about 5-8 charge/discharge cycles to get my new battery charged all the way up (or at least, reporting that it was charged all the way up.)
It could be that the firmware/chip in your original battery does not allow the cells to be “replaced”, but my suggestion is that you run your laptop all the way down every night (and then charge it all the way back up) for a week and see if anything improves.
Jay
Nathan, how did you open the EM-G320L1? There aren’t any screws and I don’t want to tear up the case by prying indiscriminately.
I just opened up my laptop Battery (for Averatec 2300). The computer wont turn on with the battery. I left it plugged to the ac adapter for at least 4 hours, still the battery charge is at 0%.
With the battery case opened up, I can see each battery is at 3.8V, totaling around 11.5V. I even measured voltage at the connector :11.5V. The cells are still good! I guess it’s the flash chip. What can I do?
Hi Jay,
My battery for my Sony Vaio is not charging anymore; so I decided to buy a new battery. The prices of the battery in Japan however is about $250.00, so I stated thinking about repairing the battery. Your explanation was clear and very helpful. Thanks very much. I am going to try and replace the cells. Wish me luck.
Thanks
Regards
Dev
Jay, I just replace 6 batteries in a Toshiba battery pack (quite a task when you have low quality soldering tools).
So far it is charging and has the power to boot up the laptop. Problem is… it is DRAINING LIKE CRAZY! I got 6x 2200mAH batteries and I believe the old ones were 1800ish maybe.
I’m about to do a 2nd full charge and see how it goes. Is this normal for the first few recharge cycles?
Quick update:
Still draining battery for the 1st time but at 6% it doesn’t seem to down anymore.
Duc Tien,
If by “Draining like crazy” you mean that after the first charge the battery level indicator goes down rapidly (during the first discharge), then yes, this matches what happened to me.
The best I can come up with is that the charge control circuit thinks that it is still using your old cells, so when it sees a lot of current leaving the cells it figures that they are rapidly getting close to their “zero” point, and makes the percentage of battery left indicator drop appropriately.
In my experience, my laptop would continue to run for quite a while after the battery indicator reached the zero percent mark. (as in, 20-60 minutes!).
After several (5-6) full charge/discharge cycles, the charging circuitry eventually learns that the new calls were “better” than the old cells. (In my case, the battery capacity “increased” by about 10% each charge/discharge cycle.)
Jay
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Hi, I repair a 336962 battery for HP. I changed all the cells, but when i put the battery on my laptop, the battery appears with a red X. What can I do?
Thans,
César
César,
It is possible that your HP battery control chip does not allow cell replacement. Alternatively, the red X may go away after several charge/discharge cycles (if the battery is working correctly despite the red X).
Jay
Hello,
I am interested in running a radio transmitter from a laptop battery (Model#BATCL50L) then recharging using the laptop. I am not able to find the battery’s output connection.
Is their an internal disconnect that is used when the battery is unplugged?
Thank you
Martin Lee
+1 408 898 4095
Hi I have a DEll laptop. The batery keeps charge only 30 min. I bought the laptop about 1 year ago. Is it possiblefor me to repaire it?
thans
mohsen,
I don’t know if the Dell batteries firmware allow the cells to be replaced or not. You will have to ask somebody who has done it for a DELL battery. (Or just try it yourself.)
Jay
Hello Jay, thanks a lot 4 your valuable info. I wanna ask something:
1. How to determine whether the cell is death or still alive? Can I test it individually (in pair maybe)?
2. Is it OK to mix the new cell with the old one? (in case not all cells are die)
3. How to determine the problem is the cells or the charging circuitry?
Thank you Jay, maybe a bit too much questions eh? I’m sorry for that. Would you please send me a copy of your answer to my e-mail? I’m not always connected.
Erdwi,
> 1. How to determine whether the cell is death or still alive? Can I test it individually (in pair maybe)?
You would have to test them individually. Charge the cell, and then discharge them through a load (motor? Lightbulb?) and watch how long it takes to drop X amount of voltage to estimate it’s current storage capacity. Obviously, if the cell does not hold a charge at all it’s completely dead.
> 2. Is it OK to mix the new cell with the old one? (in case not all cells are die)
The cells you use should all be at the same stage of life (either all old or all new). Otherwise your battery will only last as long as the weakest cell.
> 3. How to determine the problem is the cells or the charging circuitry?
Replace the cells. If it starts working, it was a problem with the cells. If not, it was the charging circuitry, replace that.
Jay
thanks a lot Jay, I hope you dont mind for more question. I want to test my old bat.
How can I recharge the battery without my laptop? can I just connect them to an adapter? If my battery is 3.6V what voltage should I set the adapter?
Thank you