Some of the first Sony Discmans included rechargeable batteries. These batteries were nickel metal hydride batteries (because of the technology of the time) and are now well past their service life. The new hotness in battery technology is lithium — it offers greater power density, lighter weight, and a multitude of ready-to-go, off the shelf cells. What if someone were to create a new battery pack for an old Sony Discman using lithium cells? That’s exactly what [sjm4306] did for their entry into this year’s Hackaday Prize.
The Discman [sjm] is working with uses a custom, Sony-branded battery based on NiMH technology with a capacity of around 500 mAH. After carefully measuring the dimensions of this battery, it was replicated in plastic with a 3D printer. This enclosure was then stuffed with a small lithium cell scavenged from a USB power bank.
The only tripping points for this build were the battery contacts. The originally battery had two contacts on the end that fit the Discman exactly; these were replicated with a small PCB wired up to the guts of the USB powerbank. The end result is a direct, drop-in replacement for the original Discman battery with a higher capacity, that’s also rechargeable via USB. It’s a fantastic project, with the entire build video available below.