This is a most interesting multi-authored paper from Denmark’s Riso Laboratory.
Its main intent is develop two different ways to predict the overall performance of lead acid batteries in renewable energy systems, and particularly those involving both wind and solar.
Current methods are diverse and based on varying assumptions. Few have been adequately validated. Further, most are based on manufacturers’ data gained by methodology that is only barely relevant to remote power system use.
This paper investigates two different methodologies. One is based on a cycle counting approach, the other links known stress factors with recognised battery damage mechanisms. Both are combined with their own battery performance model that links predicted battery longevity with actual usage in terms of simulated or measured charge/discharge patterns.
Apart from the paper’s main purpose, it contains a great deal of valuable information on various damage mechanisms – in particular the relationship between battery longevity and Ah throughput.
The paper is substantially mathematical (particularly in its use of integral and differential calculus) – and whilst some parts are hard to follow it is good to see a rigorous approach taken with a subject that only too often lacks it almost completely.
Essential reading for those truly interested in this field.
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