It might be enough to power a home at night.
If you have enough solar generation to power your home through the day and just use the batteries at night while you sleep, you've just got a fridge and some heat. 2kW won't power a large furnace, but if you live in a decently mild climate, you could power some space heaters or electric blankets.
Also, let's not forget that some of us have natural gas service, so our furnaces, stoves, and dryers don't need much electricity (just need enough to power the blower, ignition, drum, etc.). I'm not ready to go totally off-grid, but I would consider one of these battery packs to move some of my daytime electricity usage to night time and take advantage of better rates. Payback would be in about 5 years. Also, the battery bank could get me through most power outages since most power outages where I live are only for a few hours tops.
I'm going to do some research, but this could be a really good idea for me!
But if power is cheapest at night, and you're using the most expensive type of replacement energy how is this going to pay for itself? I can't see this paying for itself in 5 years if you still have to purchase the solar panels, plus installation charges for everything.
I'm just curious. My energy rates in Iowa are dirt cheap. But I have to run the furnace a lot in the winter and run the AC a lot in the summer time - even at night.