This article attempts to give a guideline answer to the question: “How long will my battery last”  by examining the typical expected lifespan of the most popular types of batteries, namely: Flooded Lead Acid, Gel, AGM, Lithium Ion, and Lithium Iron Phosphate batteries. 

The expected lifespan or useful life of a battery is usually expressed as an expected number of cycles the battery can perform before not being able to hold enough charge capacity to be considered of useful capacity anymore, which in turn can be used to estimate the lifespan in years based on how a battery is used. 

A cycle is defined as one discharge and one subsequent recharge of a battery. It can be a 100% discharge and recharge, or a 10% discharge and recharge, both of which count as a cycle but with differing effects on the life expectancy of the battery involved. This means that if the same battery is discharged only 50% each time, it will have a much higher expected cycle count, and thus expected lifespan than if it was discharged 100% each time. 

Depth of discharge (DOD) is the main variable affecting the battery’s lifespan. If you need more information about DOD, then read our article about what Depth of Drain (DOD) is in a battery and why it is so important, by clicking here:

In addition to the depth of discharge, the rate at which the battery is charged and discharged can also affect its cycle life. Rapid charging and discharging can cause excess heat to build up in the battery, which can damage the battery’s plates and also shorten its lifespan.

Given that there are so many factors that influence battery lifespan and performance in the long run (more so in certain battery types than others), it is hard to give an exact expected cycle life for most batteries as all manufacturers will quote test results under specific conditions, but we have taken various sets of data for these battery types and combined them to obtain expected cycle lifespan ranges for three depth of drain conditions, 50%, 80% and > 80%. 

The table below compares the typical life expectancy in cycles one can expect given three depths of the drain (DOD) and the effect of deep cycling on the different types of batteries. 

Battery Type50% DOD80% DOD>80% DOD
Flooded Lead Acid300 – 500150 – 200< 150
Gel500 – 1000200 – 500< 200
AGM500 – 1000200 – 500< 250
Lithium Ion500 – 1500500 – 1000500
Lithium Iron Phosphate5000 – 100003000 – 60002000 – 4000