I bought a Powerbook Duo 280c from 1994 at a flea market last weekend. It works but the battery is long dead. This is a thread about rebuilding old laptop batteries.
First up, the battery itself. It's 10 4/5A NiMH cells. I don't know about the stock cells, but the replacement cells have 2000mAH each.
Inside the duo are the cells and a few electric components.
The transistor-looking thing is a DS2401 - basically a serial number chip. It stores a unique ID number that can be read over a one-wire interface.
The longboi is a KLIXON 6MM81AA-04, a temperature sensor.
There's an unidentified component wrapped in heatshrink, and a 250A fuse (for real?!) in line with the connection between the 'innermost' batteries.
I've rebuilt a few duo batteries, and this is the first one I've seen with a plastic 'frame' for the nickel strip. The other ones used a simple flex PCB to attach the nickel strips between cells.
You might be wondering how I'm attaching the cells and nickel strips -- dude, you can buy a USB-powered spot welder for fifty bucks. Works well enough, but it has to charge for a while so that's why I'm pausing this thread for a few hours.
https://www.amazon.com/Portable-Machine-Welding-Equipment-Storage/dp/B092DB5R3S
After everything is put back together we can put the shells on and test it in the Powerbook. There's a tool called 'Battery Reconditioner' that will give you the serial number and verify everything is connected correctly.
After that, it's just a tiny bit of JB Weld around the shell. One side at a time, clamped in a vise. This part will take about a day, but after that I've got a brand-new battery.
Benchoff
Kevin Karhan 