So even if they can get the 'installed' price down to < 30% of what it is today (some corners can be cut for stationary applications) then there is still another barrier to be crossed.
All in all this is extremely exciting because manufacturing batteries at this scale will surely lead to economies unseen before but Lead-Acid has an 80 year head-start and is very hard to beat when weight and density are not a major factor.
After all the one reason why we have Lithium-ion is because of weight and power density.
Laptop and vehicles have a lot in common that houses versus laptops and vehicles do not.
Which you absolute cannot get in any market. If you could, everyone would do it because the supply cost per kWh including replacement would beat regular power company power.
EDIT: Just went back over my old calculations for this. The basic problem is that you trade off against the cost of peak electricity, not your solar.
So you can essentially assume off-peak and shoulder power is used for charging, and then you use that to offset your most expensive period. The question is then "how efficient is charging" and "how many cycles do you get from the battery before replacement".
Even at $100/kWh, the math is a near miss rather then a clear win as far as I can tell still.
