Thinkpads Forum

Hello.
I have two 42T4632 with message "consider replacing your battery".
Is there anybody who changed cells in battery?
Please share your experience - how open cover, which cells better to use (manufacturer, capacity) etc.
Thank you in advance.

Welcome to thinkpads.com!

42T4632 is the 8 cell (22++) battery for the X60/X61. Otherwise known as 40Y7003 (the generic marketing part description). I know that some people have replaced the cells in other Thinkpad batteries, typically ones for much older systems as it's hard to find new battery packs for them. My understanding is that most recent battery packs, probably including 40Y7003, have an intelligent circuit in them that must be "kept alive" (have power maintained at all times) otherwise they will refuse to work, even with new batteries. There may be a way to re-start them as I seem to remember reading something like that.

Taking apart the battery pack usually means cutting it with a knife or rotary cutting tool. The two halves of the plastic shell are either glued or ultrasonically welded together. Putting it back together may be a problem as you most likely have to use some high-strength glue or epoxy, capable of bridging the gap that will probably exist because you have cut away some of the plastic.

It might be cheaper to find a forum member or eBay seller in Russia or one willing to ship there. Currently, there appear to be some new, genuine IBM/Lenovo batteries on eBay. One seller ships to Russia, with the total cost at US$80 (less any required import taxes/surcharges).

If you use your X60/X61 on an UltraBase, then you may have to worry about some aftermarket batteries not fitting properly. If they do not have exactly the same dimensions, you may not be able to dock the laptop and battery to the UltraBase.

ref: http://support.lenovo.com/us/en/documents/pd011806
ref: http://www.batteryrefill.com/laptops/ibm/92P1171.phtml <--- battery re-cell service I used many years ago for 600-series battery; fairly expensive
ref: http://www.ebay.com/itm/321714192042
ref: http://forum.thinkpads.com/viewtopic.php?t=108655 <--- comparison of factory and aftermarket 8-cell X6 batteries
ref: http://forum.thinkpads.com/viewtopic.php?t=116288 <--- comparison of factory and aftermarket 8-cell X6 batteries

I've taken apart a few genuine Lenovo X61 tablet batteries and found they were not in fact glued or welded--- just a *ton* of tiny little alternating plastic snaps/hasps, much like how the front lid bezel fits. Guess the wrong location (or direction to 'pop' it) and you'll probably destroy the hasp. You'll probably need one battery you messed up while opening to use as a guide for properly opening later batteries...

[Also-- not disputing some of these things might be glued, the ones I've opened weren't]

I have *not* tried to replace the cells. I was tapping into the batteries to add additional current sense circuitry.

I think it's necessary to reprogram the battery's charge controller to reflect the capacity of the new cells.
It's a daunting task though.

thanks for your replies.

Yes, I have replaced cells. And yes, I killed a protective circuit in a genuine Lenovo battery in the process by disconnecting it without keeping its input leads powered. I have not yet found a way to revive it and I have tried everything I can think of.

It should be possible to clip an alternate source of current limited 16V to the plus and minus wires of the protection circuit before you unsolder the cells. Not sure if the protection circuit will go open circuit if you do not keep power on other two cell wires, though.

I have looked on Ebay as well as locally and frankly, it does not seem to pay to replace the cells.... the prices I have found are approximately equal to the cost of a non-OEM replacement battery. The only reason I can see to replace cells is if you want to keep the original Lenovo battery protection circuit. The protection circuit in some of the non-OEM batteries will trigger the battery manager "non-genuine" warning as well as causing a higher self discharge rate than genuine OEM batteries. I have one that discharges about 0.75%/day even with the laptop shut down.

As for opening the battery case, all the ones I have opened have been glued and took a great deal of care with a wide flat knife to slowly break the joint. To close them, I just use packing tape.

Paul

I've got 2 dead 8-cell and a dead 4-cell sitting around. One of them reports 10% remaining capacity, one doesn't report at all and the last one says "Failed from normal wear" and doesn't even try to charge.

Does anyone know if replacing the cells on the ones that don't report / say failed would be worth trying? Before I invest in nice new cells I'd rather figure out if it's possible. Happy to try some experiments if there's a method that's likely to work...

Any success stories?

R

I am not 100% certain, but I believe that genuine IBM/Lenovo batteries that report "failed" are permanently failed. Not sure about the clones.

Paul

None of them are clones. I guess I'll poke around at it and see what I can do.

R

You might look at the individual cell voltages. I have always wondered what makes a cell declare itself dead.

Paul

Looks like there are ways of resetting the chip's failure flags. Unfortunately, the version of the software that supports writing (not reading) costs $300...too much for just an experiment, at least for my wallet. Group investment (only half joking)? I might try reading it out and seeing what I can find.

R

Is this software that runs on the PC and talks to the battery? Interesting.

Sort of. You have to crack the battery open and attach to the controller chip. It's an SMBus / I2C device.