What Really Happens After the First Year

Battery degradation is inevitable, yet it is often underestimated in solar lighting design and evaluation. Understanding how batteries age is essential for predicting long-term system behavior.

Capacity fade is gradual, not linear

Battery capacity does not drop suddenly. It degrades gradually, influenced by temperature, depth of discharge, and charging behavior. Early performance often masks future decline.

Depth of discharge accelerates aging

Frequent deep discharge cycles significantly reduce usable life. Systems designed with minimal energy margin force batteries into stressful operating ranges more often.

Temperature amplifies degradation

High temperatures accelerate chemical aging, while low temperatures reduce usable capacity. Both effects compound energy imbalance over time.

Why early tests are misleading

New batteries perform optimally. Systems that appear robust in the first year may struggle as capacity declines, revealing marginal design assumptions.

Engineering takeaway

Battery aging is predictable.
System failure is often the result of ignoring that predictability.