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Panels have 25 year warranty. Batteries 2,000 discharge warranty (19 years).

I am glad that you live in an area where solar cells will eventually pay for themselves. It does not work that way where we are at.

How do you figure that your batteries will survive for 19 years? I am not sure that you have a clear understanding of how batteries are used in a functioning solar system. Even if you had them only on a self leveling trickle charger most batteries will not be in useful condition after 19 years even if you never used them.

The warranty is the guarantee that the batteries will work fine, with the understanding that their efficiency degrades over time to the point that at the end of their 2,000 guaranteed discharges (basically a discharge per day at night time means a little over 19 years to get 2,000 discharges) they're still working at 70%. I don't have to "figure" out the "how". The supplier and vendor have to figure that out or replace them. That's what the warranty frees me from having to worry about.

My solar chargers built into my inverter does the trickle charge when it charges them every day, but the trickle charge goes into effect when the SOC (strength of charge) gets nearly full. That's one of the nice things about 48V lithium batteries. Until they're nearly fully charged, they can be charged with high voltage and amperage.

Six lithium batteries holding 5 kWh each, but the warranty expects me not to discharge them beyond 80% (down to 20% SOC). So count them as 4 kWh useful storage each -- 24 kWh total.

For reference, I consumed 82 kWh yesterday on a hot Alabama September day running the A/C as hard as Bama's gonna run over Florida this weekend. I bought 40 kWh from the power company even though it was cloudy half the time and even had a small rain. So I bought about 49% of my power. And I have my inverter set to pull from the grid when my SOC gets to 30%, not 20%, to try to extend the life of my batteries beyond the 19 year warranty. That's on a not so nice day for solar (high demand from my power but less sun to power it for free). On Saturday I bought 28% of the power I consumed (39.8 kWh bought of 82.5 kWh used), and on Friday I bought 17% (6.6 kWh bought of 39.8). During the spring I have lots of weeks where I produce over 90% of the power I consume (lots of sun in the spring to keep the batteries fully charged, but not running the A/C nearly as much especially at night, so my batteries are often only 50% drained until the sun comes back up). Overall I'm looking at 70% of my power coming from solar. I'll take that. And my lithium batteries aren't even being drained the full 80% the warranty allows.