The round trip of a battery refers to one complete recharge – discharge cycle. Two factors influence how much of the energy a battery stores actually reaches the user, in other words its overall efficiency. We review round trip efficiency and battery performance, in terms of battery design and overall state of health (SOH).
Battery Energy Conversion and Round Trip Efficiency
We express round trip performance as a percentage of output energy, over input energy received from a charger. A higher value means that energy conversion is more efficient, than a battery with a lower score.
From a user’s point of view, this means the battery can store and release energy more efficiently, and remain useful longer. Yet surprisingly, we seldom find articles on the internet around this topic.
Round trip efficiency and battery state of health are none the less important factors that should affect our purchasing decisions. Perhaps round trip performance will receive a mention in European Union battery passports? We will have to wait and see.
Battery design sets the underlying factors in place, that determine new battery round trip performance. Jeremy Wu, writing in Linked-In, suggests that battery model, temperature, charge and discharge-rate all play a defining role here. Customer behaviour then influences battery state of health further, as it ages with use.
More Lessons from State of Health and Battery Efficiency
We can delay or defer lost energy in a battery, resulting from internal chemical reactions and other losses. We can also assess the overall state of a battery’s health at a given moment, in terms of round trip efficiency and battery capacity, as well as voltage and internal resistance. However, our take away should be that we cannot put back what we have already lost. Good battery care is still the key to longer battery life.
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Health of Car Batteries – A Review
