Contact the manufacturer as they provide the warranty. Buy from a reputable company in the first place instead of one with cheap unknown brands. My installer, panels and inverter have hardly lost any performance after 7 years. Never had a problem or issue since installation. Have saved the cost of them over the 7 years. Am enjoying little cost in electricity bills as only in winter some extra electricity used and rest is for fees. Do your homework. I don't have a battery backup as it would not be economical for me to run yet. I live in Perth where solar is worthwhile. I also have no gas which is a big saving and I use a solar hot water system which rarely needs the electric booster in winter so I leave it off most of the year. Replace them with a long term installer. They don't only service their own installations and this time do it properly. May cost a bit more for good, reliable brands.
