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I Recently aquired an IBM ThinkPad 701C. This is a 486DX4/75 laptop, read more about it on Think Wiki. Well it arrived via USPS, and i was pre-warned by the seller on EBay that they could not remove the battery, and there it was... an exploded battery pack.
So, I did a bit of googling and read that the battery could be easily rebuilt, but the case was a pain to crack open (one poster claimed breaking it into 8 pieces). So I procedded to clean the battery up a bit, it had corrosion seeping out all over. I then peeled off what remained of the label and broke out a utility knife and started tracing the seam with it. This wasn't very effective, so i tried my trusty swiss army knife, the normal pocket knife blade.
Success! The knife was the way to go. After about 10 minutes of using the tip to scratch away at the seam, it basically fell open.
Those batteries are awefull long... But they are the same diameter as regular AA NiMH rechargable ones.
I pried the pack from the lower half of the case. The batteries are unlabled, but the battery pack is 9 cells totalling 10.8v @ 1.9A, this means 9 cells of 1.2v each and 1900mAh.
The energizers at my local Wal-Mart are 1.2v @ 2500mAh, that should work nicely and give an added boost to runtime :)
Now onto cleaning up the innards. It is a complete mess.
A half hour later and a few cans of my favorite beverage....
Hrm, the ThinkWiki shows this is a "dumb" battery... Guess i need to learn a bit more, because what is that chip there...
Aha, I guess even "dumb" batteries need to know voltage of the pack, what type of battery it is charging, and the temperature. This is where the DS2334 comes in, such a cool little chip, read more about it in the PDF Data Sheet.
Here is a graphic I made in case i need to recreate this board...
But it appears to be in serviceable condition, The corrosion hadn't made its way up to the chip itself, just its pins.
Ok, off to Wal-Mart to buy 9 replacement batteries... "Part 2" to follow when i actually try to rebuild this battery pack :)
Then a "Part 3", Taking apart the rest of the laptop to clean the corrosion and replace the CMOS battery. So far I have only removed the 4 T1 torx screws and the T6 ones from the underside of the machine, it allowed me to get the battery out of the machine. Peering down into the machine it doesn't look like any acid made its way outside of the battery compartment. The laptop still boots up fine (past the CMOS battery warning), and goes right into Windows 95A that the previous owner installed.
Forward to Part 2
Forward to Part 3
