Battery Life

Updated: Dec 27, 2019

Batteries are a very important feature of most alternative power systems. The energy is stored in the batteries for use at a later time. The battery is a silent worker that delivers energy until it quits of exhaustion and old age. It is more prone to failure than most other parts in a system. Much is expected but little is given in return. With a shorter lifespan than the host device, battery replacement becomes an issue, and the lifespan of a battery is not necessarily fixed by the manufacturer. It is dependent on a number of factors, including its type, chemical changes in the battery, age, conditions under which it is used and how it is generally used.

Naturally, batteries wear out with age and use. However, it is therefore necessary for battery users to understand battery life and the factors that determine the lifespan of a battery so they can effectively manage performance. Keeping in mind the high cost of batteries and the short period that the manufacturer’s warranty covers the battery (Warranty periods for batteries last for just twelve months.), it is important to know the best battery choice for your power needs and how to effectively manage performance.

You can read all about inverter batteries and how to maintain them here.

Batteries have three distinct measures of life

  • Run-time

  • Shelf life and

  • Cycle life

Run Time

Run time refers to how long a battery or battery pack will run on a single use. This is not fixed for any battery and it also depends on the appliance on which the battery is run, but users can find a clue in the depth of discharge for each battery.


Depth of Discharge is how much energy is discharged from the battery before it is charged to 100% again. For instance, a battery with 50% will have 50% of its energy capacity discharged, before it begins charging again. It also means that a battery can only be discharged at 50% and never below. Most inverters and chargers do this automatically. Otherwise, users should not use a battery below its depth of discharge.