“When the voltage of the battery drops below 12V, and the whole page is coloured in blue, the solar charge controller shuts down the system and the website goes offline.”
Low-tech Magazine runs on one 30W solar panel and a lead-acid battery in Barcelona. The page colour shows the battery level, and a long cloudy stretch takes the site down. That is the deal, stated up front. Every other site burns grid power around the clock and promises 99.99% uptime nobody needs.