When you see information about batteries one thing you will often see is the number of cycles they will claim to be able to provide in their lifetime. This figure can be anywhere from 2,000 cycles to 5,000 or even 6,000 cycles.

At first glance it might seem that the higher the number of cycles, the better the battery will be but in fact there are many factors that can affect the true number of cycles you will get out of your battery over its lifetime. Generally the more you take a battery below its recommended depth of discharge the fewer cycles you will get out of the battery.

One cycle is taking a battery from fully charged down to its recommended depth of discharge before charging it up again.

Battery specifications usually state a specific depth of discharge per number of cycles expected over a batteries lifetime. This might be 4,000 cycles at a DoD of 80% or 4,500 cycles at a DoD of 30%. If you were to only look at the number of cycles the second example of 4,500 cycles would look like a better option but in fact you would get much better performance from the first battery with fewer cycles as it has a much greater depth of discharge available to be used.

When you see a certain number of cycles quoted you need to make sure that you can verify the figure and it is not just a figure quoted by the battery manufacturers with no real proof. If the battery technology is new it is difficult to really understand how the battery will perform in real life situations as the figures have only been estimated in laboratory conditions. This is the case with many of the lithium ion batteries that are now coming onto the market.

When a battery technology has been around for more than 4 or 5 years you are more likely to get realistic cycles based on real life experience. This is the case with lead batteries or sodium nickel batteries.

Also when you have a smaller battery the battery may actually cycle more than once a day depending on its usage and how it is charged. This means trying to equate number of cycles to a batteries life in terms of years may not be a straightforward equation. This is another reason why larger batteries may actually be better value in the long run.

When batteries are tested, the standard testing temperature is 25oC. This is the optimum operating temperature for most batteries. When batteries operate at temperatures above or below 25oC their performance is affected and as a result their number of cycles will reduce.

If you recognise the value in utilising battery storage and would like to understand more about different battery characteristics please visit our website at http://quantum.gridedge.com.au/ or feel free to contact us for more information at admin@grid-edge.com