The Electronic Industries Association (EIA), and other authorities, specify standard values for resistors, sometimes referred to as the "preferred value" system. The preferred value system has its origins in the early years of the last century at a time when most resistors were carbon-graphite with relatively poor manufacturing tolerances.
Like humans, batteries function best at room temperature, and any deviation towards hot and cold changes the performance and/or longevity. Operating a battery at elevated temperatures momentarily improves performance by lowering the internal resistance and speeding up the chemical metabolism, but such a condition shortens service life if allowed to continue for a long period of time.
If the battery were a perfect power source and behaved linearly, the discharge time could be calculated according to the in-and-out current. “What has been put in can be taken out in the same form over time” is the argument, and in our example a one-hour charge at 5A should enable a one-hour discharge at 5A, or a 5-hour discharge at 1A. However,
The purpose of a battery is to store and release energy at the desired time and in a controlled manner. This section examines discharges under different C-rates and evaluates the depth to which a battery can safely be depleted. Chapter 5 also observes different discharge signatures and explores how certain patterns can affect battery life. But first, let’s look at charge and discharge rates, also known as C-rate.