Minor updates on Powerwall battery
5/1 Bloomberg News – SolarCity Taking Orders for Tesla Batteries Starting at $5,000 – You can place an order now for a Powerwall backup battery. The 10 kWh backup can be purchased for $7,140. Price for just the battery is $3,500, so the inverter and installation will run you $3640. Installation only runs about $1,500 I think, which means the inverter is running around $2,000. Need to add that into all of the previous calculations I made. That further reduces the economic value of batteries, solar, and going off-grid.
5/6 – Bloomberg News – Tesla’s New Battery Doesn’t Work That Well With Solar – The two new Tesla batteries have different chemical compositions. The 10 kWh is only designed for 50 charging cycles per year. That makes it unusable for anything other than emergency backup.
SolarCity will not be offering the 7 kWh model, which can be used daily.
Article points out that the mere 2 kW output would be consumed by running one vacuum cleaner, one hairdryer, or one microwave. Pick one. You can’t run two of those at the same time.
It would be enough to run one or two of those small window air conditioning units you see.
Entertainingly, the article points out that to generate 16 kW electricity which you can get from a $3,700 generator from Home Depot, you would have to string 8 Powerwall batteries together. Since SolarCity reportedly offers no discount for multiple units, that would set you back a mere $57,120.
So, $4K or $57K. Take your pick. Oh, and on day 2 of a massive blackout, you could still be using the generator.
5/8 – Bloomberg News – Tesla’s Battery Grabbed $800 Million in Its First Week – Cost of the occasional use Powerwall battery is $3,500, exclusive of installation, inverter, permits, and other hardware. At 10 kWh, that is $350 per kWh.
The daily use version is $3,000 for just the battery. At 7 kWh, that is $428 per kWh.
The commercial version is Powerpack. It is a 100 kWh battery. It is priced at $250 per kWh, or $25,000 per unit, exclusive of installation and all the hardware.