Photovoltaic System Batteries

There are actually three issues when it comes to a PV system batteries, most people only focus on their calculation on the batteries itself.

First of all, the additional wiring and the additional fire risks.

Second, you would need a hybrid inverter, which costs significantly more than a standard inverter.

Lastly, the batteries.  The calculation really hinges on the lifespan of the batteries.  The expected lifespan has goes from hundreds to some claims 4000s.  Even if we assume best case scenario having 4000 discharge cycle at 90% caps, it is less than 11 years assuming single full discharge nightly, will the battery be able to pay itself back within that time?