PowerBook 5300 batteries

I recently flogged a couple of Apple PowerBook 5300ces on eBay. Their only problem was that the batteries were dead. A replacement costs around £90, about 3x the value of the entire laptop… I had a spare battery, so I took it apart (it’s all glued, so needs a bit of force). inside are 12 NiMH solder-tagged cells all a little larger than standard AAs, a thermal cutout wired inline, and a little 2-wire serial number chip attached to a couple of the extra contacts on the casing. The battery is rated at 1900mAH, which considering the size of the cells is not great. I checked for sizing, and you can easily get two 6-AA battery holders in. Wiring up the thermal trip is easy enough, and you can leave the serial chip in place. This could get you 2500mAH (with current top-end AAs) at a fraction of the cost of a replacement while also saving quite a bit of weight. I didn’t actually do it as was selling the laptops in their battery-less state, but it was an interesting exercise nonetheless.