As batteries age, their ESR goes up. Eventually, they will no longer be serviceable. A battery measurement tool like the Hioki BT3554 lets field service technicians monitor the help of batteries over time. In this video, see how it can be used to measure a live UPS battery. This episode was sponsored by Hioki.

There are three capacitor measurements you need to know how to make: capacitance, leakage current, and equivalent series resistance. Capacitance is easy to measure if you have a current limited supply or can use a resistor. Apply a voltage, then time how long it takes to charge up. You might need to use an oscilloscope or even an Arduino for the second part.  Leakage current is the easiest of the three, apply a voltage (ideally…