Guys, forget the batteries because you can't backup more than 10' to a miner of let's say 1Kwa (with only 1 battery). You will need thousands of Lead Acid batteries and will cost a fortune every 18 months.

 By the way, if you are not electrician and don't have knowledge, I don't recommend to do it by yourself because you have lot of cables to connect. At this point you have many factors to consider like cables Amp capacity, quality, connect by polarity, cables distance, modify the switchboard, etc.

 From the other hand, if you intend to connect your Grid Tie to the city pole, you might need to request a permission to do all that modification.