Domestic Lithium battery storage solutions are a good idea in principle, but presently remain unsatisfactory for a number of reasons:
(1) Lithium Battery storage and monitoring systems are very expensive - Approaching the cost of a domestic Solar system.
(2) Lithium Batteries typically last 5,000 storage cycles- Expect to replace your batteries every decade.
(3) Lithium Batteries require a monitoring system to maintain batteries at the correct level of charge.
(4) Payback on installing this technology is slow when compared with many alternative energy saving measures.
(5) Until the mass market embraces this technology, Lithium batteries will remain expensive for many years to come.