I would focus on incremental systems. Something like 10$ cellphone, 100$ for lighting, 1,000$ for PC, 10,000$ for AC.
Also, midrange UPS don't output square wave, I fact solar systems include a UPS for night time power. So, you could sell a ~3k, UPS system with bult in solar hookups where people can add pannels over time.
Also, midrange UPS don't output square wave, I fact solar systems include a UPS for night time power. So, you could sell a ~3k, UPS system with bult in solar hookups where people can add pannels over time.