Recently had a quote in Australia for >$AUD12,000 for a 5kwh battery set.
This is going to change everything to do with solar installations I think. Currently battery packs are a rarely taken up optional component.
If you can run on solar all night there's potential savings. Assume 10kWh costs $1. If you have a surplus of solar during the day and you fully deplete at night, you theoretically save $365/year. Break even is at 10 years, which coincides with the warranty.
So with a solar setup that could charge a 10kw pack each day I could almost go off grid. That would save me nearly $1000/year once you take into account daily connection charges.
So the batteries would be paid off in 3-4 years, add a few years for however many panels I need and that's a pretty decent saving for no more power bills.
Of course it depends how long they are likely to last after that 10 year warranty period - no point swapping utility bills for tesla bills for replacements every 10 years.
Well, there could be additional benefits, such as not being linked to the grid and it's occasional problems (not to mention you aren't drawing power provided in part by coal). Then again, an extended period of low solar energy could have it's own problems.
However, I might be completely wrong about how this works.