battery tester can be of many types, but the main two types are Simple and Integrated. Simple tester is a DC ammeter, it has an indicator for telling about the charge rate of the battery. Integrated testers are used according to a specific type of battery and these testers are of several types. The reason behind it is that there are several types of batteries and therefore their testers need to be different.
Integrated testers mostly hold industrial-level relevance while simple ones can be even used at home. However, these are some of essentials that electricians need to keep.