Thinkpad battery internals, repair?

[mikeh]

After getting a new battery, I decided to risk opening the old 8-cell battery, which was down below 50% of design capacity.
It would be nice if I could replace some cells to fix it.

I must have done something nasty while prising it open, or with the multimeter as

• - it no longer reports charge level to the laptop.
  - it still charges, and i can run Linux on battery, so long as I tell it to ignore the 0% battery level it sees.
  - it will not boot on battery, or even wake from suspend without having the charger connected (BIOS being natsy)

After running on battery for a while, I checked inside and found that only the flat cells were drained. The cylindrical 18650 cells are all over 4.1V still. Would this be normal behaviour, to drain one series of cells first? Or perhaps is it just because I managed to wipe the memory?
I had expected pairs to be wired in parallel.

Actually, the battery still has memory, because the laptop still reads the "last full capacity" correctly, just not the current capacity.
Any chance of fixing it now? If not, and the 18650 cells are still OK, I will use them for other things.

[orlandoinsane]

I was thinking of repairing/adding capacity to my now seemingly dead 8 cell battery for my x61t as per the guide here :http://www.instructables.com/id/Increas ... aptop-bat/

Any chance you could take some picks of the opened battery?
What kind of cells are the flat ones?

thanks

[mikeh]

The flat cells are (standard?) prismatic 50 x 35 x 10 mm. Presumably 1900mAHr, as in the 4-cell.
http://www.myk.id.au/x40-8cell-open.jpg

18650s are cheap and easy to get from dealextreme.com etc. I don't know about the prismatic ones.

Admin edit: Replaced large (~80KB) inline image with link. Please keep them small (<50KB) AND post a warning in the subject line

edit: I did shrink the image down to what I thought was a small 80k. I hate bloated pages too, but maybe that 50k limit needs updating for the 21st century Bill?
Meanwhile I will be more careful and follow policy. I do appreciate that the site pages are quite lean, even with the animated GIF adverts (no Flash!), as I am using a 3G cellphone for internet access.
Sorry to anyone still using 56k dialup.

Admin response: Well, by "large" I meant both byte-wise and pixel-wise. At 1530×482 the image couldn't even fit on my SXGA+ screen without rescaling/scrolling. If resized to 800x252 it would be about 34KB. Ray

[dozer]

huh.....as it happens, I just ended up with a similiar project myself.

A near brand-new 9-cell on my wife's T61 just suddenly stopped working.

Except in this case, although the laptop dies instantly when adapter is unplugged, pwr mgr reports this batt at -100%- charge!

Gotta love this modern brilliant technology...

I've scrapped out some ancient Dell paks for the 18650 cells before, but have never gotten one apart as to leave the plastic in condition to go back together again...

The sonic-welding or glueing that they use presents quite a problem in that regard. So my question to add to this thread is....has anyone developed a good technique for getting the welded plastic cases open in a way that allows them to be used again?

PS: Mikeh, 50KB is enough for a 640x480 pic, which is itself enough for showing most things; i.e. specific details or objects....if the photo is taken with a modicum of care (i.e., focus in on the item of interest).

There are indeed some here who are still stuck without broadband.

Myself, I get 31.2kb at best....and so I've always MUCH appreciated the owner's insistence on keeping this forum lean. I can consistently load any page here at TP-forum in 4-5 seconds. Compare that to the abysmal 40-90 seconds (I'm not kidding) for that HORRIBLE Sourceforge site.

(where the morons use dog-slow SECURE https to send PUBLIC forum pages out...ROFL)

At the same time, I'd not be personally adverse to an increase to, say, a 60-70kb limit....as that wouldn't slow things terribly...and it would allow for the few 640x48's that do slightly exceed 50kb....and 70kb might let in a few 800x600's....especially if the color-depth was kept moderate.

ps; I didn't realize the TP batt-paks had two shapes of cells in them....that seems very odd from an 'even charging' standpoint. Usually, one wants to use only identical cells in any battery. The Dell packs I have scrapped for cells used all 18650's....in two groups of 4 cells....seperate charging-ckt for each group.

pps; this Samsung-cell 3rd-party T61 pack does not show any voltage between + and - at the external connector. The older Dell and HP packs I've played with all showed some voltage there. Are TP packs the same?....or do they need logic signals from the laptop before 'turning on' power to their connector pins?

I look forward to this thread developing.....there are a LOT of potentially-fixable packs out there.

ppps; I've just begin researching pack-stuff, so I've not gotten the full scoop on this yet, but I just came across ref. to a software called "EEPRAN". Possibly something that can reset OEM pack-chips and other interesting functions like that? If anyone has info on this, or a package that -will- do things like that, please do add to the thread.

Richard

[mikeh]

Good new, the faulty 8-cell has recovered after a cyle or two, and seems to be reporting charge correctly again. It is charging to the exact same capacity as before, a touch over 50% of design.
I could find no evidence of faulty cells inside, so I guess they are just all worn.

.has anyone developed a good technique for getting the welded plastic cases open in a way that allows them to be used again?

I just used a small knife. Find a place where you can push the point in and lever it apart, then slide the knife along. When it meets too much resistance, use fingers to pry the case open, pulling the two parts apart at the point. It took a while.
You have to be careful about which way to put the knife in.

I didn't realize the TP batt-paks had two shapes of cells in them....that seems very odd from an 'even charging' standpoint.

In this case, it is very obvious when you look at the battery. It has a flat part that fits inside the laptop, and a cylindrical part that sticks out.
I was thinking of just replacing the cylindrical ones, as they are cheap and easy to get.

this Samsung-cell 3rd-party T61 pack does not show any voltage between + and - at the external connector.

That may be OK. It just means that the internal voltage has dropped below the safety cut-off level. If it has dropped to far though, the cells may be permanently damaged. And I read that some brands have an on-switch, e.g. short one of the other pins to turn on the main (+) output.

[dozer]

I just used a small knife. Find a place where you can push the point in and lever it apart, then slide the knife along. When it meets too much resistance, use fingers to pry the case open, pulling the two parts apart at the point. It took a while.

well, that didn't work with the dell packs I salvaged... ..they were freaking -welded-. Whether it was solvent-cement or ultrasonic-welding, I don't know.....but those two plastic pieces were -fused- together.

But heck, the knife is the obvious place to start with this one anyway.....see how it goes.

dozer wrote:
this Samsung-cell 3rd-party T61 pack does not show any voltage between + and - at the external connector.

That may be OK. It just means that the internal voltage has dropped below the safety cut-off level. If it has dropped to far though, the cells may be permanently damaged. And I read that some brands have an on-switch, e.g. short one of the other pins to turn on the main (+) output.

thanks....yeah, I've read of something like that, but wasn't sure it was in these T60 packs. I'll have to take a look at the laptop schematics and ID the functions of the pins.

One other thing I noticed, on my own T60p, is that doing a discharge/charge cycle on one's own does not affect the 'health indication' i.e. capacity-number whatsoever. Apparently one has to do it via the 'routine' in the software....to get it to actually rewrite the chip in the pack.

The 9-cell in the t60p is near-new...a replacement from the recall-program...only 12 cycles on it......yet it shows 55.6wh capacity out of 70-something it should have.

The pwr-manager software doesn't seem to run right when rmclock is installed.....or something.....and it 'went away' in the middle of using its built-in 'restore' routine......so I quit that, then just unplugged the AC to discharge it 'manually'....down to 3%, then a full charge...but the numbers didn't change a whit.

off-topic, but perhaps valuable to anyone interested in batts/restoring who hits this thread in a search.

R.

[poshgeordie]

I'm doing some long term development on cell replacement on T4x's, including resetting the battery 'fuel gauge'.

The basic cell arrangement is three cells in series giving 10 volts or so. To give the capacity, the 6 cell standard version has two cells in parallel, and the higher capacity three cells in parallel. The parallel sets are then connected in series to give the reqired output voltage.
The cells are the cylindrical 18650 types.

I'm not sure how different the various cases are construction-wise and if they are all similarly plastic welded, but I've got into a standard and high capacity T4x battery cases using a small flat bladed jeweller's screwdriver and plastic 'spludger' . With the spludger being plastic, it's good to stick inside the battery. Be very very careful using the metal screwdriver.
I get into the cases by starting at one end where the two halves aren't so well welded together and use a combination of the screwdriver and spludger to loosen the two halves, gradually working around the broad sides of the battery - ie not the flatter side containing the circuit board.
Once I get the other three sides loose I lift the two halves to break the remaining welds along the thin sides and it all seems to come apart without damage.

For me at present the biggest problem is getting hold of quality cells at a decent price - ie avoiding these nasty Chinese no name cells, so my preference would be for Japanese (or maybe Korean) manufactured 18650's branded Panasonic, Sanyo, Samsung, Sony etc.
In the UK prices are around £10 ($16.5) EACH!!! so buying 6 or 9 is ridiculously expensive and I've been forced to buy from a USA seller which seems daft to me.

It's very early days for me regarding removing the old cells and fitting the new ones, but the biggest problem is reassembling the new cells so that the two case halves can be fitted properly.
This means that using wires in place of the existing metal stips is out - wires are just too thick. So the metal strips from the cells to the circuit board have to be carefully cut away leaving as much length as possible.
I'd suggest starting at one end and gradually working towards the other being very careful not to short any cells or damage the cell cases. The idea of having a sand bucket is a V good idea since even momentarily shorted cells heat up incredibly quickly.
Rebuilding - start at the end you finished stripping back. Position the cell tabs so that cell pairs can be soldered together together with the metal strips as needed. Bear in mind that the case halves hug the cells so try to avoid the tabs sticking up and fouling the case. It will take a bit of planning to get it right but it should be fine.

Once the cells sets and the circuit board are connected tentatively connect it to the Thinkpad and see what happens, but constantly monitor the body temperature of the cells to make sure they are relatively cool and there isn't one overheating which could indicate a rebuild problem.

I appreciate that a photo set would be good and I'll probably get something together when I've got it all worked out in the next few weeks / months.

Onto resetting the battery count / fuel gauge - very early days and I refuse to buy software to do this so it's over to Linux /open source. There is a very good article here, but there's a problem with the compiled kernel and I think it's needs redoing from scratch so that it'll work reliably. Can anyone with Linux experience help here?

There's a paid for version here

Running the batteries I've rebuilt without resetting the circuit have worked fine. The cells were sold to me at half capacity, so the first thing I did was to discharge the battery down so that the output voltage on the TP battery monitor was 9.8V. This meant disabling every 'alarm' etc so that the laptop didn't shut down. I've read somewhere that the battery shouldn't be discharged below this voltage but can't remember where.
I then charged up until the battery monitor voltage /power indicated full 100% charge. 100% indicated was reached quite quickly but this is the memory effect left over from the old cell set. I think that if if did a couple more complete discharge to full recharge, this effect would switch over to the new set.
overall the battery set works fine except the battery count's wrong.

Apologies for the huge length of the post but it's a good topic which needs much more input.

[SMA]

poshgeordie, what kind of electronics do you find on that circuit board? In particular, what chip(s)?

[poshgeordie]

I'll need to go into work which won't be until next week, but I do know that the 4400 6 cell was an actual IBM board, whereas the 6600 9 cell looks like a remanufactured Chinese one with a completely different one - possibly some generic board used across a number of manufacturer ranges?

I haven't got any genuine IBM 9 cells in stock.

Will get back to you next week.

[mikeh]

Thanks Posh for that info. Some points:
- X40/41 (and X60?) 8-cell batteries are not wired in pairs. Each cell is controlled individually.
- The battery will not allow you to over-discharge. It will shut off automatically. This is separate from the laptop settings.
- the "reconditioning" software doesn't do anything special. It just disables the alarms and does a full discharge/recharge cycle (or few?) to reset the known capacity.

I bought a couple of old-stock but unused X40 batteries. They were made in 2004, (and never recharged till now) but still holding 93% and 97% charge, amazingly. So not so much need for me to fix the old one now.
I have set the laptop to only charge to 80% normally, to extend the life. In Linux, that is done with the tp_smapi module. That also lets you read cycle count, first-used date, etc.

I don't expect the $4 cells from DX would last this long, but it would seem a sensible way to get an extra year or so out of an old laptop.

[poshgeordie]

Hi Mikeh

Just checked out your photo and I see what you mean - the layout for the x series is completely different to the T4x ones and look a lot less complicated to replace.

I guess what's needed is a series of strip down / build up photos for the batteries used across the model ranges.

[mikeh]

I just took a shot at replacing a bad cell pair on the old X23.
Had my sand-bucket ready in case of pyrotechnics.
Was almost done when a solder-joint failed (Its hard to solder steel),
and now the battery completely refuses to either charge or supply power.
Just a moment's power loss is enough it kill it, apparently.
Looks like no chance or recovery, unlike the X40 battery, which just lost its charge-level info temporarily.