It's all dependent on the model, however across the board our power packs have +3,500 cycles. Each cycle consists of a complete discharge and recharge. The lifespan of the product will depend on overall usage and the frequency of running through cycles. We find that a power pack will typically last from 8-20 years. And even after the rated cycles, the power pack will still operate, it will just have reduced run time (i.e. <80% of original). The typical pay back period on our products is 2-3 years when compared to traditional generators.