Battery Depth Of Discharge

The term depth of discharge (DoD) is used to indicate what percentage of a battery can be discharged relative to the total capacity of the battery. DoD is a good way to determine what type of battery is best for certain applications and can also give an insight into the expected lifespan of a battery such as the one in your car or truck. At Bashi’s we always want you to get the most out of your new battery and take this metric into consideration at all times.

To put it simply, the more your battery is charged and then discharged, the shorter its life will be. Many batteries are unable to be completely drained without significantly impacting their lifespan and this is why manufacturers will specify a maximum recommended DoD to maintain optimal performance. The chemistry present in most batteries, including lead-acid and AGM, has a direct correlation between their DoD and their cycle life.

depth of discharge

Depth Of Discharge & Battery Cycle Life

Cycle life is the number of cycles a cell can perform before its capacity drops to the point it begins to impact its performance. This means it is also used to determine the lifespan of your battery, however that is also affected by how much of a battery’s capacity is used and that’s where it ties into depth of discharge. If a battery is frequently drained to its maximum DoD it will have a shorter lifespan than one that was regularly discharged at a lower percentage.

If we look at a typical lead-acid battery as an example, we could expect 200 to 300 discharge/charge cycles. There is a wide margin here because we have to account for the batteries DoD and other factors such as operating temperature. The reason these numbers might seem lower than you would expect is due to grid corrosion of the positive electrode, expansion of the positive plates and the depletion of the active material. These factors are more common when a battery is operating at a higher temperature.

depth of discharge

The Impact Of Temperature On Your Battery’s Lifespan

Just like us, your battery has a preferred temperature for optimal performance and lifespan. When the temperature starts to go north of 30° we run the risk of overheating which will negatively impact the battery’s lifespan. Going the other way, cold temperatures mean the battery has to work harder at a higher voltage to charge which again has an impact on the lifespan. For the most part we can’t control the temperature near your car or truck battery which makes consulting an expert before picking the right battery a great idea.

The Manufacturer & Chemistry Also Impacts Depth Of Discharge

The manufacturer and composition of the battery is also an important factor when deciding what battery is going to give you the most value. A good example on the chemistry side are Gel batteries which use silica (sand) to turn the acid into a thick liquid. Gel batteries have a very high DoD and are often referenced as deep cycle batteries as they are designed to be regularly discharged using most of their capacity.

Talk To An Expert About The Right Battery For You Needs

While this technical talk might seem a bit daunting for something as simple as a car battery, the good news is you can talk to an expert auto electrician at Bashi’s Auto Electrical to find out what battery is the right one for your needs. We stock a massive range of options and have you covered, everything from your standard car through to campers, trailers, heavy transport and more. Our decades of experience means we can give you valuable insights into getting the most out of your new battery.

To talk with a qualified auto electrician about finding the right battery for your vehicle, give us a call on 07 5495 7333 or contact us online.