Hello Y'all, If I was going a non lead acid it would be with the new saltwater batteries. They survive a 100 percent DOD for 3,000 cycles if I remember correctly. Big and heavy while limited temperature range as they have reduced performance above 104f also to my memory after emailing the comapny engineer. Certified cradle to death they are a true green battery. There is a blog on the AltE website. They do a price comparison and if I remember someone did some experimenting with the midnight classics with them. I do not kniw if that was a special firmware or what. New technology and bound to go down in price with improvements along the way. That is the way I would go. As far as grid backup on Mwatt scale there is alot of research being done on a liquid metal technology.
Best regards,
Mike