The Complete Handbook of PDA Batteries

Chapter 1: Understanding PDA Batteries

What a PDA battery actually is

When a reference handbook says "PDA battery," it is not talking about a generic AA cell or a sealed external power pack from a camera. A PDA battery is a purpose-built, rechargeable lithium-ion (Li-ion) or lithium-ion polymer (LiPo) cell that is shaped and terminated specifically to fit one or more models of a personal digital assistant, a rugged field terminal, a barcode scanner, or an industrial mobile computer that runs a non-standard operating system such as Palm OS, Windows CE, or a proprietary real-time OS. These devices were sold from the mid-1990s through the mid-2010s, and many are still in regular commercial use. They are not curiosity pieces. The battery is the single most failure-prone component in that hardware, and it is also the one part that is most likely to be replaced incorrectly.

Inside the plastic or aluminum housing of a PDA battery, you will find one or two flat Li-ion pouch cells. In most designs, there is no over-complicated battery management system (BMS) as you would find in a laptop or an electric vehicle. The protection circuit on a PDA battery is usually a small printed circuit board (PCB) with two or three integrated circuits. The most common components are a charge-protection IC that monitors cell voltage, a fuel-gauge IC that tracks state of charge, and two or three surface-mount MOSFETs that act as switches to cut off the cell from the terminals in the case of