You are correct, it should be around 7 years.

My supply is great, I only ran out of power once (when I was not at home to manage power consumption), during a 4h30 power outage, and an overcast day, with my geyser also pulling power. If I was at home, I could switch off the geyser manually to reduce the consumption.

The current week we again had long 4h30 outages again, with sunny days, with no problems, even with the geyser coming on!!

To me, solar is worth the expense, here in South Africa.