Comment by cogman10

You don't need to replace the whole setup, just the batteries. All the power electronics and interconnects are already there and will last as long as they last.

You also don't technically need new batteries almost ever. Batteries (typically) don't really die, they just lose capacity. After a 15 year runtime instead of storing 10mWh they now store 7mWh. That's still 7mWh. After another 15 years it'll be down to around 5mWh.