Tesla Powerwall, page-16

reading the article again, it seems the inverter could be included with the price. The article is a little confusing because it quotes the price of 10k for the Powerwall but then says it will install the Powerwall and an SMA inverter without explicitly stating whether the inverter is included in the quoted price or not.

here are details on the inverter:
http://cleantechnica.com/2016/03/19/tesla-powerwall-compatible-storage-inverter-unveiled-sma/

though, you get what you pay for:
"It has a maximum discharge power of 2.5 kilowatts"

This inverter is a stripped down version of SMA's flagship inverter product. The inverter will limit the output of the battery, which means in certain situations you are not going to get as much use out of the battery as you would with a more capable inverter.

I see the market starting to offer stripped down batteries (lithium with small capacity, lacking built in cooling, shorter warranty) and inverters (low power) in an effort to offer the lowest cost storage product, but this low end of the market is going to be very competitive with low margins IMO. Better to offer batteries at the mid- to upper-end of the market to those serious about storage and who want quality components. Redflow isn't aiming at the low end of the market and I think that's a good thing - their battery is a high-tech premium solution so why not market it that way.